H.M.S. Hood Association-Battle Cruiser Hood: H.M.S. Hood Reference Materials - ADM 116/4351: Report on the Loss of H.M.S. Hood

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SECRET

N.L. 16248/41

Appendix III

Series E

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SERIES "E"

Appendix III

SECRET. MINUTES OF EVIDENCE TAKEN AT A BOARD OF ENQUIRY HELD AT DORLAND HOUSE, REGENT STREET, S.W.1, 29th August, 2nd, 3rd, 4th 5th September, 1941. BY A COMMITTEE APPOINTED TO ENQUIRE INTO THE LOSS OF H.M.S. "HOOD" IN ACTION WITH THE GERMAN BATTLESHIP "BISMARCK" ON 24th, MAY, 1941.

MEMBERS OF THE BOARD.
Rear Admiral H.T.C. Walker, Royal Navy (President)
Captain R.G. Duke, Royal Navy
Captain L.D. Mackintosh, D.S.C., Royal Navy

LIST OF WITNESSES

Name and Rank or Rating.	Question Nos.
1. Captain J.F.B. Carslake, R.N	1 - 27
2. Mr. D.E.J. Offord, R.C.N.C.	28-49 & 194-209
3. Dr. G. Rotter, C.B, C.B.E., D.Sc.,	50-80
4. Commander R.F.P.Maton, O.B.E., R.N.	81-130A
5. Commander R.F. Knight, O.B.E., R.N. (Retd)	131-193A
6. Captain R.C. Woollerton, O.B.E., R.N.

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EVIDENCE OF CAPTAIN JOHN FOSTER BARHAM CARSLAKE, R.N.

Taken at Dorland House, Regent Street, S.W.1., On Friday, 29th August, 1941

The witness was cautioned in accordance with K.R. Chapter II.

1. Are you an expert on cordite explosions?

No.

2. Are you an expert in high explosive detonations?

I know a fair amount about these but there are may (sic) questions in answering which I would not trust my own judgment. 3. Would a 15" or 8" shell striking the HOOD's side abreast the torpedo tubes detonate a war head with pistol in it? No, not unless it penetrated and detonated inside the mantlet. If it detonated outside it would not detonate a warhead.

4. Would a direct hit, whether from a shell or from a splinter detonate a warhead with a pistol in it?

If the shell detonated on impact with the warhead, it would detonate the warhead. If the shell hit the warhead but did not detonate, it would not detonate the warhead, for this reason. To detonate the head with pistol in it, the projectile would have to hit the detonators without detonating them but cause them to enter the primer and then detonate. This I consider so improbable that it should be neglected. As regards the splinter, unless the velocity of the splinter is extremely high - in the order of 3,000 - 4,000 ft. per sec. It would not start detonation in the warhead, and this velocity could not be achieved by a splinter or a shell which perforated the mantlet and then entered the head.

5. Am I correct in assuming that the gist of your statement is, that owing to the presence of the mantlet round the warheads, it is very unlikely that any detonation of a shell in that vicinity wouldexplode the warhead?

Yes, unless detonation of the shell occurs inside the mantlet.

6. Is it reasonable to suppose that a shell that did not actually burst inside the mantlet could explode a warhead?

From trials it is reasonable to suppose that a shell which did not burst inside the mantlet could not cause the warhead to detonate.

7. Would one warhead detonating in a mantlet cause an adjacent warhead to detonate?

From trials it has been shown that there is no greater risk of detonation when warhead is fitted with primer and detonators that when not fitted. If both warheads are in the same mantlets, that is, if there is not an armoured bulkhead between them, they will probably cause each other to detonate.

8. In other words, if one of the HOOD's warheads exploded - that would be likely to do so?

Yes.

9. Would one or more of the warheads detonating one side of HOOD detonate those on the other side?

Definitely not.

10. If the air chamber burst would the warhead be driven forward with sufficient violence to cause detonation if it struck a closed mantlet door?

The velocity with which the warhead would be driven forward, if it was driven forward at all, would depend upon the cause of the burst and the nature of the fracture and the condition of the tube. It is considered most probable that the expanding of the air vessel would lock it behind the gas check ring of the tube and that the tube would burst without giving the warhead any appreciable forward velocity. If the warhead were driven forward into the armoured door it is considered that this would not cause the detonator to enter and then to fire, because quite a number of trials have been carried out, firing torpedoes against armoured plates to test the safety of the pistol which has proved satisfactory.

11. Your previous reply pre-supposes that the air vessel has been burst due to a hit. Do air chambers ever burst for more unexpected reasons?

Yes. Very rarely.

12. What would be the visual and aural effects on an observer outside the ship on the side of those tubes, of the detonation of one or more warheads in the HOOD with mantlet doors.

I should expect to see a dull reddy brown flame with smoke which might be light brown if the detonation was partial, or dark brown towards black of the detonation was complete. I should expect it to envelop the part of the side where the tubes were situated down to the waterline. The main direction of the protruberance would be horizontal from the position of the mantlet doors because though H.E. gasses will vent at very high velocity, the major direction will still be that of least resistance. In the case of the HOOD, above the warheads are the mantlets and the forecastle deck, both of which are 2" thick, whilst ahead are the armoured doors only held relatively lightly. The inertia of the doors is however, considerable and I should expect that the doors and the side would move outwards, the doors travelling at a greater speed than the side, and the flames spreading over the side, but the net protruberance being greater in this horizontal direction due to this being the direction of free-est venting. The noise of the warheads would be extremely loud and sharp. I would expect the noise to sound louder than the 15" guns of the ship.

13. Would it be possible for any or all of this noise to be heard outside the aural range?

Some of the noise no doubt would be, but sufficient would be within the aural frequencies to produce the impression as suggested in the answer to the first part of the question.

14. You have made it quite clear to us the reasons why the mantlet doors would probably be blown open but we are not quite clear if you would expect the deck above to open up or the 3" protecting plates forming the mantlet also to blow up.

I would expect the mantlet, the forecastle deck and the ships side to be nearly demolished, but that the major venting would have been as I suggested, horizontal. Immediately after the explosion, it is anticipated that the observer would have seen a gap in the ship's side, probably some 15 or 20 ft. radius down to the top of the 12" belt.

15. Would you expect the boat deck also to open up?

Yes, I would expect the boat deck above the tubes also to be blown away.

16. Can you point out on either of the exhibits the colour of the smoke and flame that you would expect from a good detonation of the warhead?

I would expect flame to be R.I. on Exhibit 1.

17. Does the amount of flame and smoke caused by detonation of a warhead give an indication of the damage likely to be caused?

Yes. If there is a lot of smoke which is not very dark brown the detonation is poor and the damage small. If the smoke is dark coloured and less in quantity the detonation is good and the damage great.

18. Do you consider a strong fire, such as that from a quantity of cordite would detonate a warhead?

If the flames were round the head it would probably cause the head to burst due to gas pressure, set fire to the T.N.T. which might burn to explosion, with perhaps, some partial detonation of what was left of the charge. In other words the effect would be small.

19. Have you experience of the effect on ships structures of detonations and explosions?

I saw the INVINCIBLE's magazines blow up from close range; I have experienced being mined in H.M.S. OCEAN and I joined the INFLEXIBLE shortly after she had been mined before any repairs were done. I also experienced the effect of the ship I was in being hit by a heavy shell in the Dardenelles.

20. What do you think the effect upon the HOOD's structure would be of the detonation of one or more warheads?

I would expect that not more than 2 warheads would be involved in the detonation and that they would blow away the 5" belt and the ship's side above to be blown away for the distance of perhaps 15 ft. each side, also the forecastle and boat deck to be blown away for a distance of perhaps 20 - 30 ft. each side. I should also expect the decks below to be blown in down to the level of the armoured deck. I would anticipate that the armoured deck might be bent but not fractured.

21. You replies to our questions as regards the appearance and effect of the detonation of one or more warheads in HOOD obviously refer to the detonation of the two warheads which were actually in the tubes. As the spare ones are not opposite the mantlet doors and therefore one imagines, would not have such an effect as regards blowing them open, will you now tell us what you expect the effect of the detonation of the two upper warheads would be?

From the appearance to the outside observer I would expect that the horizontal protruberance which is previously associated with the blowing off of the mantlet doors, would be much less pronounced or absent. With regard to the damage, I would expect greater damage to the boat deck and less to the armoured deck, though I should not expect that the total would be very different.

22. Would you associate a phenomena resembling a ball of fire ascending vertically with the detonation of warheads?

No, I would not. Captain Carslake added that he had based his replies on the MUNCHEN trials which were carried out with warheads of similar weight and were reported in G.01437 of about 1920.

23. You told us that you saw the INVINCIBLE sunk. Will you please say how far off you were and describe it.

I was on the bridge of the INFLEXIBLE which was two cables or less astern of the INVINCIBLE. I was looking at the INVINCIBLE at the time. She was struck by a salvo which hit her in the neighbourhood of "Q" turret. There was an appreciable interval after the enemy shell had hit her before the resulting explosion was noticeable. The first thing I remember seeing was the turret roof blown up into the air, and a great column of flame and smoke and debris which went up into the air, I would judge some 600ft. or more, where it opened out into a mushroom of dark brown smoke with pinkish coloured flames. The ship broke clean in half and though the INFLEXIBLE put her helm hard over, the two halves of the INVINCIBLE had sunk and grounded on the bottom. By the time we were on her quarter the two halves had sunk so that the bows and stern were sticking up some distance apart, with the other ends of the sections on the bottom.

24. Could you describe the noise when INVINCIBLE blew up?

My immediate reaction after the excitement was that I had heard no noise at all and I remarked upon this at the time to another Officer on the bridge, who said that the noise "had nearly broken his ear drums." MY deduction was that the whole of my attention had been concentrated in sight, whereas he had not seen the explosion but heard it first.

At the request of the Board, Captain Carslake then made a pencil sketch of his impressions of the explosion, which are reproduced as Exhibit 7.

25. Has your impression of the blowing up of the INVINCIBLE always remained clear in your mind?

Yes.

26. What do you think the effect upon the HOOD's structure would be of the detonation of one or more of the after 4" magazines?

I don't feel I am competent to express an opinion about 4" magazines.

27. Then can you tell us what the effect of the after 15" magazines would be?

I think undoubtedly it would blow the ship in two, and be generally similar in appearance to what happened to the INVINCIBLE.

At the conclusion of his evidence Captain Carslake also sated that:

"On receipt of the questions from Rear Admiral Wake-Walker which formed the basis of the questions I have answered to-day, I wrote my answers to the questions and read them to Captain G.B. Riley who was Head of Torpedo and Mining Inspection and has had a very wide experience of trials with high explosives. He entirely agreed with the answers which I have written out and which were substantially the same as those I have given to-day."

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EVIDENCE OF MR. DUDLEY EDWIN JAMES OFFORD, R.C.N.C.,

Taken on 2nd September, 1941.

The witness was cautioned in accordance with K.R. Chapter II, and stated - I am the Officer appointed to assist the Board from the point of view of ship construction.

28. Can you tell us what would be the effect in H.M.S. HOOD of one or more torpedo warheads exploding in the tube mantlets?

First of all as regards damage to the ship and secondly causing further explosions elsewhere. The torpedoes in HOOD were situated on the upper deck and contained a protective box or mantlet. The deck immediately over the torpedoes was 2" thick and constituted the upper flange of the strength girder of the ship at this position. Over this was the shelter or boat deck which was of normal thickness. Below the torpedoes was the upper deck, three quarter inches thick, except within the mantlet box where there was an additional plate 2" thick. I have no direct knowledge of the effect of torpedo warheads detonating in such a position inside the ship. I do not know anyone who has. Trials have been carried out in which warheads have been detonated in the open air immediately over a ships weather deck, but the effect in these instances bears little relation to what would happen if the warheads were well confined with a ship. I have however, some direct knowledge of the damage resulting from shell and bomb explosions within ships, and with the detonation of high explosives it is the weight of explosive and not the type of container that has the main influence on the damage, except for that part of it which is caused by splinters. Plate No. 6 in the Damage Control Handbook OU.6331/39 shows the damage caused to H.M.S. MONARCH by detonation below decks of a 15" S.A.P.C. shell containing about 105 lbs. of T.N.T. Similar damage equally effective but less spectacular was caused in H.M.S. MALBOROUGH BY THE DETONATION OF A 250 LBS. S.A.P. bomb containing just under 50 lb. Of T.N.T. The explosion in this latter instance was accompanied by dark grey smoke in large masses rising as high as the fore top.

The Committee were shown photographs from the report of MARLBOROUGH bomb trials dates 3rd February, 1932 (G.0926/32) to substantiate the above remarks.

The above instances may be regarded as somewhat extreme examples. A more average example is shown in Plate No. 7 of the Damage Control Handbook. This shows the damage caused to the strength deck of H.M.S MARLBOROUGH by a 500 lb. S.A.P. bomb containing about 100 lb. T.N.T. detonating just below the strength deck, which was slightly under 2" in total thickness. The deck was bulged upwards and some of its fastenings disturbed. It was approaching the stage where it would cease to function as a satisfactory strength member. The detonation was accompanied by flash and billowing masses of grey black smoke which rose several times as high as the fore-top. In Job No. 74 a 250 lb. S.A.P. bomb, 50 lb T.N.T. detonated below a specially vented strength deck, caused a large deflection of the deck and destroyer its fastenings, so as reduce most seriously its usefulness for strength purposes.

The above examples leave no room for doubt that the detaonation of even one of HOOD's warheads - that is about 500 lbs. of T.N.T. would destroy the strength deck for a considerable width and blow out the ship's side for a considerable depth, certainly well below the waterline. At the high speed at which HOOD was steaming, water would be scooped into this ship side rupture and its momentum would be sufficient to carry away the transverse bulkheads in the after end of the ship. The additional weight of this water would soon become more than the weakened strength deck could withstand and the ship would break her back, the after end falling away and sinking rapidly, the forward end sinking more slowly probably stern first.

29. Could you define more closely the use is the word 'rapidly' as regards the sinking of the ship?

This is very difficult to say, but the time I am visualising is somewhat less than 3 minutes.

30. You have stated that the ship's side would be blown away to below the waterline; will you tell us (a) how far down you would expect this to occur and (b) as this entails armour being blown away, what happens to the backing plates for the 12" belt?

For one warhead I should expect only a comparatively narrow "V" shaped rupture in the ship's side plating extending down to the lower edge of the slope of the main deck, which is about 7 ft. below HOOD's probable action draft. The ship's side armour, although able to resist considerable blows from outside the ship, has little other than its own inertia to resist blows from the inside. HOOD's belt armour was not fitted in the same way that armour is fitted in our modern capital ships, that is to say, HOOD's armour has no keys between the plates and no rabbetting between the tiers of plating but is secured to the 2" backing plates by armour bolts disposed about one every 10 square feet. I should expect therefore, that one or more plates would be blown overboard, because if the fasteners were destroyed at one end of the plate only, the water rush, due to the ships speed would strip the plate from the ship.

With the detonation of 2 warheads I should anticipate a substantial increase to the damage to the ship's side, particularly in view of the overhead enclosement of the charges. In this case also, I should anticipate fracture in the main deck itself below the tubes.

31. You said at the beginning that the explosion of one warhead would fracture the strength deck - what damage do you think would be done to the shelter or boat deck?

I think the shelter deck would be bulged up and split over a considerable area and torn away from the ship's side. The latter would be split and town outboard as a continuance of the "V" shaped crack already referred to. With 2 or more torpedoes the damage would, of course be appreciably increased, but I would prefer not to give any figures as to the extent of the damage.

32. So it is your firm opinion that the explosion of one warhead would fracture the boat deck as well as the forecastle deck?

Yes.

33. To produce the effect of this very rapid sinking, i.e. something in the order of 3 minutes, how many warheads do you consider would be required to detonate?

With one warhead I do not anticipate any serious initial damage on the main deck and therefore the first rush of water would be above that deck only. The tearing of the main deck would have only occurred when the after end had become sufficiently heavy to cause the breaking of the back to continue.

With two warheads, however, I consider there would immediately be a rupture in the main deck of sufficient magnitude to allow relatively large volumes of water to be scooped into the engine rooms. The after end would then break away and sink relatively more rapidly than in the case of one warhead only.

34. Would you expect all the bulkheads abaft the after engineroom bulkhead to completely collapse in succession, bearing in mind that the ship was stopping very rapidly?

I should not expect all the bulkheads to collapse, but certainly the engineroom bulkhead at 259 and possibly the one abaft it at 280.

35. As a result of what you told us, what attitude would you expect the stern of the ship to take?

If an complete rupture occurred in the region of the mainmast, I should expect the after end to founder with the stern in the air. If, however, only a partial rupture took place in the region of the mainmast, then the after end will sink bodily and drag the fore part with it.

36. In addition to the damage you have described would you expect heavy debris to be thrown up vertically or in any particular direction?

With one or more warheads there would be a considerable amount of debris. Although the tendency would be to throw it more or less equally in all directions, there is so very much more on the deck than on the ship's side that one would expect the optical effect to be mostly of debris thrown upwards.

37. Would you expect such heavy debris as the mainmast or one of the after turrets?

I would expect part of the mainmast and gear such as boats and ready use lockers to be thrown in the air, but I should expect no disturbance whatever to the main turrets of the ship.

38. Will you now reply to my question about other explosions being caused by the detonation of warheads.

I understand that at the time of the action it is most probable that all hatches and doors giving access to the 4" H.A. magazines in HOOD were closed. It is my opinion, therefore, that the detonation of one or more warheads would not cause an explosion in any of the 4" magazines. Even less would I anticipate it to cause an explosion in the main armament magazines. The detonation of the warheads might, however, cause the explosion of the U.P. ammunition, which I understand was stowed on the forecastle deck in HOOD, but I do not consider that this would have any appreciable effect upon the dmage caused to the ship.

39. If one 4" magazine blew up, would it (a) blow up any of the other 4" magazines, (b) would it blow up the 15" magazines, (c) would it blow up the warhead?

There are six 4" magazines in the after group, namely two in the hold, two on the lower platform deck and two on the upper platform deck. I consider there is a reasonable chance that the explosion of the contents of the upper magazine immediately abaft 280 bulkhead, would not result in the explosion of the others in the group. My reasons for this are (a) the relatively small amount of ammunition in this magazine (b) the proved "safety" of 4" fixed ammunition, and (c) experience of the magazine venting and similar trials in Job 74.

The explosion of either of either of the magazines just below the one referred to may possibly cause the explosion of those above it, and less possibly, of those abaft it. In this event I should anticipate a ripple or pulsating effect rather than a single flash or flame from the explosion. The explosion of any of the 4" magazines abaft 296, would, I consider, cause the explosion of the after 15" magazines. My reason is that the 15" cordite is less "safe" than 4" fixed and a considerable amount would necessarily be exposed as the main armament was in action. I should not expect the explosion of any or all of the after magazines 4" and 15" to detonate the warheads in HOOD's torpedo tubes.

40. In other words you would expect that an explosion in any of the 4" magazines except the upper one between 280 and 296 to explode all (4" and 15") after magazines?

Yes.

41. If one or more warheads blew up how would you expect the explosion to vent?

With the detonation of a high explosive, a large part of the resulting damage will be caused by the pressure wave which is propagated more or less equally in all directions. The part of the phenomena due to the expansion of the gasses from the explosive would tend to vent along the line of least resistance with a natural preference to ascend if possible. It follows therefore, that the pressure wave will rupture all but the strongest structure in the vicinity of the warhead. This effect takes place a fraction of a second before the expanding gas effect and therefore the latter will, in general, ascend through the rupture caused by the former.

I should expect to see issue directly above the torpedo tube position masses of curling blackish smoke, which would rise up like a cauliflower or mushroom effect, becoming lighter and greyer as it dispersed. I should anticipate a dull red flash of only very short duration, i.e. a mere fraction of a second.

42. Can you explain whereabouts in HOOD you would expect this venting to be evident?

The source would be immediately over the warheads but the magnitude would be such that the base of the column of smoke would appear to occupy a considerable portion of the boat deck in the neighbourhood of the mainmast.

43. Would you not expect some flame or smoke to be apparent through the ship's side?

Some, yes, but a relatively small amount; so small as to probably not be observed by a watcher some little distance away.

44. If the foremost upper 4" magazine blew up without exploding any other magazine how would you expect it to vent?

The venting of a magazine depends upon the degree of violence of the explosion. In a magazine containing a relatively small amount of cordite such as the one you mentioned, and if this burns in not too short a time, complete venting would be possible up the line of access - embarking hatches etc., With more violent burning the pressure will rise so steeply that the bulkheads or decks of the compartments will be destroyed. Against pressure from below, decks are usually much weaker than bulkheads and therefore the most likely to vent is by way of the deck over. Once the vent has started the static pressure becomes changed into a gas rush which has a sort of hose effect. This gas rush is unlikely to turn appreciably from its straight line path in order to vent through a line of relatively weak structure. Thus I should expect the 4" magazine referred to, to vent up through the extreme after end of the boat deck, i.e. abaft the mainmast, either as a gas rush through the hatches, or in the more violent case, by the blowing up of the deck itself.

45. You have told us that the blowing up of any of the remaining 4" magazines would also probably blow up the 15". How would venting then take place?

In this case sufficient venting could not possibly take place through any of the natural openings in the ship. The decks, however, would be blown up and in the extreme case the ship's side blown out. With the explosion of 15" magazines I should expect to see masses of smoke and a somewhat sustained flame issue from the barbettes and gun houses and I should expect that the turret roofs would be hurled into the air to a considerable height. I would here like to say that it is unlikely in a ship of HOOS construction that any considerable portion of the outer bottom plating would be blown off, without also destroying most of the frames in the vicinity.

46. What would be the structural effect on the ship of the after 15" magazine blowing up?

If the explosion of the 15" magazine was of extreme violence the whole of the after end of the ship in this vicinity would be burst asunder, i.e. the longitudinal bulkheads, inner and outer bottom would be forced outwards leaving the after end of the ship completely detached from the forward end.

47. Do you think the explosion of a warhead in the mantlet would produce a splash effect alongside the ship similar to that which occurred in the high explosive bomb on H.M.S. MARLBOROUGH?

The splash effect in the photograph you refer to, is produced by the debris blown over the side of MARLBOROUGH by the explosion. This bomb was in a position where there was a considerable amount of material capable of producing such debris. In HOOD the only material to form such debris would be the mantlet doors, parts of the mantlet, ships side armour and plating behind armour. Thus, although I would expect some splashes their number and extent would be far less than in the photograph of the MARLBOROUGH bomb. (The photograph referred to is to be found in G.01094/32.)

48. What would you expect to be the appearance to an observer outside the ship of one or more 4" or 15" magazines exploding?

In none of our trials have we had a magazine fully stowed. Thus I have no direct knowledge of a fully stowed magazine. I have already described where I should expect the vent to first manifest itself, I should expect the phenomena to have some appreciable duration, particularly as regards the emission of smoke. I should anticipate a fairly bright yellow flame and smoke of mixed colours, some dark, almost black and some white almost like steam. I believe it has been reported that the magazine explosions in BULWARK, NATAL and VANGUARD were accompanied by a rumbling noise like distant thunder.

If the HOOD'S 4" magazines were involved first, I should expect a ripple of pulsating effect in the flame. For the 15" magazines I would expect a much greater amount of flame and smoke and after the main explosion some evidence of continued emission of flame and smoke. There would, of course, be a great deal of debris, and for the 15" magazines the turret roofs. In the event of an explosion of extreme violence I should expect observers in a ship as near as the PRINCE OF WALES to feel some shock from water hammer effect.

49. We know from evidence that a fierce fire burned somewhere on HOOD'S boat deck. What do you think the effect of that would be on the explosives stowed on the boat deck?

Before the war a large number of experiments were conducted to ascertain the probable effects of fires upon or in ready use lockers. All these trials indicated that such stowages when in weatherproof lockers suitably vented were reasonably safe. It was judged that the effect upon the safety of the ship would be practically nil. The conclusions from these experiments have been fully confired (sic) by war experience. There have been a number of cases where splinters of other effects have caused fires in ready use lockers but in no case has serious damage occurred to the ship. In several cases I know that

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The wood on which the lockers were situated, was not more than scorched. The above remarks apply only to ammunition such as 4"fixed or 5.25 separate. I have no knowledge of what would happen with U.P. ammunition, but I do not anticipate that its effect the ship would be much different from that already described.

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Dr. G Rotter, C.B, C.B.E., D.Sc.,

SECRET

EVIDENCE TAKEN AT DORLAND HOUSE, REGENT STREET, S.W.1.

2nd September, 1941

DR. GODFREY ROTTER, C.B., C.B.E., D.SC.,

Director of Explosives Research,

Research Department,

Woolwich.

Representing

C.S.R.D.

Shrewsbury

The witness was cautioned in accordance with K.R. Chapter 11.

50. Have you had much experience in observing magazine and cordite explosions?

I have seen cordite exploded under a number of conditions. I have seen a large ignition of cordite in a factory and have seen trials which were carried out at Hoo Fort in which we tried to simulate the conditions of storage of cordite in land deports and set fire to it. Then of course, I have read various reports. I have not seen actual explosions on board ship. I have had representatives present at trials in which ships magazines were exploded in H.M.S. MARLBOROUGH and I know roughly what their observations were.

Cordite can either burn or detonate. When it functions normally in a gun, you get a yellow grey to reddish brown smoke according to the size of the gun and a very large report. When it burns under less confinement it tends to give less of a report and the smoke becomes more reddish. In the Hoo Fort trials which simulated a land service depot, the smoke issuing from that was brownish red due to oxides of nitrogen. When cordite detonates the report is very much sharper than when it burns and also the smoke is greyish.

51. How can you detonate cordite?

If you detonate a C.E. primer alongside cordite S.C., the cordite will detonate. The bursting of a shell alongside a bundle of cordite sticks would probably make it detonate. Whether the cordite detonates or not depends to some extent on the way it is held up to the explosion, in other words the confinement of the individual sticks next to the shell. If the cordite were strongly confined it would undoubtedly detonate. It is difficult to make cordite detonate as a result of a fire.

52. Can you tell us what the effect is likely to be on 4" fixed ammunition in a magazine, of the penetration of a large shell?

If the rounds are stacked relatively close together the explosion of the shell would possibly initiate detonation of several rounds and this might spread to the full contents of the magazine, blowing it up. On the other hand, if the shell did not explode actually in the magazine but set fire to a portion of the contents, then the rounds would be expected to explode intermittently. It is unlikely that the noise would be heard at any great distance from the ship.
As regards the 15" magazine, assuming that certain of the lids had been taken off the cylinders, the ignition of the cordite in one 15" charge case by a shell fragment, would certainly ignite the cordite in the cylinders which had been opened. The probability is that the whole of the charges in the magazine would explode. In regard to the outside effects, there might be a small preliminary report and some flame, followed after a very short interval by a loud rumbling explosion which would blow the ship up. It is not clear that the preliminary explosion would be heard outside. The smoke from such an explosion would tend to be reddish in colour with a large golden flame. If a shall had detonated the 15" magazine the contents might have detonated simultaneously and a sharp explosion rather than a rumbling, would be heard, and the smoke would tend to be more greyish. Such detonations might occur whether or not the lids of the cordite cases were on. If the lids of the cases had been on - all perhaps except a couple of cylinders, there is a small chance that the ignition of one charge would not explode the whole contents of the magazine. The chance of that happening in a ship where magazines are non venting is much less likely than in a vented magazine.

53. If the cordite magazine detonated do you consider it likely that a ship in the neighbourhood would feel the shock of the detonation through the water?

Yes, I would expect that ships situated not a great distance away would feel a tremor through the water.

54. Would the burning or explosion of the 4" magazines cause any effect in the 15" magazines?

If there was a fire in the 4" magazines which did not cause the whole of the contents to explode simultaneously but rather of the nature of a piecemeal sort of explosion of individual rounds, it would be improbable that the 15" magazine would be exploded at least until some considerable time afterwards. Such explosion might conceivably occur through conduction of heat if the bulkhead separating the two magazines was not thicker than half and inch and not otherwise heat insulated.

If the whole of the contents of the 4" magazine exploded simultaneously it is quite probable that the bulkhead would be ruptured and a flame penetrate to the 15" magazine which would cause its explosion practically simultaneously. Alternatively it is possible that fragments of a detonating shell might be projected through the bulkhead and cause ignition if the 15 inch cordite.

55. Assuming the 15" charges are contained in brass cases 1/8" thick how near do you consider a 15" shell would need to explode to cause the detonation of the cordite in that case?

Practically alongside. On the other hand the shell exploding a little way away from such a case would project very hot fragments through the cordite and set fire to it.

56. In that latter case you would expect, I presume, explosion and not detonation of the cordite?

Yes.

57. In view of what you have just told us, it does not follow therefore that a 15" shell detonating in the 15" magazine will detonate the contents of the magazine.

No, but it would probably cause ignition of so many charges that the whole of the contents would burn and blow the ship to pieces.

58. In other words you would then anticipate explosion of the magazine and not detonation?

That is so. The difference observed outside would, I think, be mainly in the colour of the smoke.

59. Observing that the 4" ammunition is fixed and is in a closed non venting magazine, do you think it probable to get a piecemeal explosion of the charges? What I mean is either one or two charges will explode and no further effect will follow, or else a sufficient number will explode to cause the explosion of the complete magazine.

A piecemeal explosion could occur if there was combustible material in the magazine to create a fire which would burn for some time.

60. What do you think would happen if there was no such combustible material?

One or two rounds might fire and the remainder be left unignited.

61. Have you had much experience in observing the detonation of T.N.T. and other high explosives (a) in the open and (b) below decks in ships?

I have observed the detonation of TNT and other high explosives in the open on numerous occasions. I have been present at certain trials which were carried out in the MONARCH in which 55lb. Bombs were burst between decks.

62. You have just seen the plans of the torpedo arrangements of H.M.S. HOOD. If one torpedo detonated in its mantlet what do you think the effect would be on the remaining torpedoes on that side of the ship?

The torpedo in the same horizontal compartment would be detonated but the torpedoes in the compartment above or below as the case is would not be detonated, although their contents might be scattered and partly burnt.

63. What would you expect the visual and aural effect to be to an observer outside the ship of the detonation in the HOOD of one or more of her warheads?

A sharp explosion would be heard. The side of the ship in the immediate vicinity would be blown out. It is highly probable that you would see a flash mainly out from the ships' side and some above, and dense black smoke. A lot of the light superstructure would be ruptured and smoke would be coming out for some time afterwards.

64. Would you expect any white smoke?

If the lower warheads were detonated and ruptured the mantlet above, the explosion might well cause a partial ignition of the TNT in the upper warheads, with the formation of white smoke. Conceivably this might be blown forwards on top of the black smoke.

65. I was 10 or 15 miles away and I saw a tremendous column of flame shoot up somewhere about the mainmast of HOOD. It was pink or red in colour with white and black streaks in it, and shaped like an inverted cone. Its direction was obviously vertical and it was very quickly surmounted by dense clouds of black smoke. The flame had a certain duration though this was very short. There is one thing I forgot to mention - that for about 3 minutes before this sheet of fire appeared, I had seen a fire burning with a very clear flame on the uppermost deck that I could see, about the same part of the ship that the explosion eventually came from. What did I see?

The fire which was seen on the deck before the main explosion may have been U.P., petrol, or possibly flame coming from below deck. It is not though that a deck fire would have been sufficient to cause the detonation of the warheads two decks below but this might have been brought about by a fire below deck. The warheads might also have been exploded by a second hit (it is understood that the ship was hit twice). Their explosion might possibly project unconsumed 4" and UP rounds above into the air in a burning condition, giving rise to the streak effect but other debris might also cause this. It is not thought, however, that the explosion of the warheads would be sufficient to cause the ship to sink.

66. What would you expect to be the effect on the HOOD'S armoured belt as shown in the diagram of the explosion of two warheads?

The explosion of two of the warheads would blow out the 5" plating. It would also blow away the lighter decks above and the 7" belt would be splayed open. The 12" belt might not have been blown away. The armoured deck would tend to get blown in and split.

67. Would you not anticipate it opening up the ship's side below the waterline?

Not sufficient information to answer this question satisfactorily, but it is not though that the ship would be sunk by the explosion of the warheads only.

68. Is there any difference between naked H.E. charge and closely confined charge with the same type of H.E. such as you would get in a shell or bomb, with regard to the damaging effect, except splinter damage?

Provided the H.E. is brought to detonation in both cases the heavily confined charge will give rise to less blast but more fragment effect than the unconfined charge.

69. Is the detonating effect of a warhead fairly equal in all directions?

Yes, approximately, but if you ignite the explosion at the rear end you get an enhanced effect in the forward direction as compared with igniting it at the forward end. The difference may be something like 10 per cent but not more than that.

70. I was half a mile away from the ship and I saw a fire burning fiercely on her boat deck. It was very hard to see its dimensions, but its centre was in the vicinity of the mainmast. It burnt with a clear flame. I am rather vague as to the smoke, if any. Suddenly there was a blinding flash which startled me so much that I could not give at all a clear description of its colour or the smoke that accompanied it, but there was definitely a vertical direction and it occurred somewhere about the mainmast, but it may have been a little further forward or as far aft as "X" turret. The next I saw was that the ship had disappeared, all except her bows, and where she had been was enveloped in a cloud of smoke. What did I see?

The fire on the boat deck may have been U.P.'s. It may also have been burning gasses escaping under pressure up a shaft from a fire in a magazine. If so, the fire would probably gain in intensity subsequently igniting the whole of the cordite in that or in an adjacent magazine. An explosion in the 15" magazine would give rise to a big flash upwards in the form of an inverted cone directly above the magazine. The smoke might well have been greyish brown in the first instance, later turning to a deep reddish brown, such as I noted when 1.5 tons of cordite was exploded in Hoo Fort.

71. If you saw a flame followed by a dense column of white smoke which almost had the appearance of steam - this smoke later turning to black - what would you expect that to be?

It is difficult to account for the change in colour, presuming the smoke to have been as described, white and black. It is possible that the different appearance was not an actual change in the colour of the smoke but due to the intensity of illumination by the flash of the explosion dying away. The black smoke might have been produced by the detonation of TNT or from burning fuel oil. Dark grey smoke might also be caused by the detonation of cordite. Both smokes might have been present, the white smoke disappearing (e.g. steam) rather than changing.

72. In the previous question describing the upward rush of flame, supposing I saw a ball of incandescent fire, say 100ft. diameter, what would you think that was caused by?

That might readily have been due to the projection of cordite charges only partly ignited, taking fire in the air, or ignition of projected oil fuel.

73. I saw an upward rush of flame in the shape of a funnel, rather a thin funnel and instantaneously the ship was enveloped in smoke from one end to the other. The flame gave me the idea of a blow lamp and its colour was between "D" and "E" on exhibit 1. What would this have been caused by?

The flame might readily have been produced by the explosion of cordite in a magazine and the burning gasses escaping under pressure up a shaft. The smoke may have been due to cordite or possibly to some of the oil fuel taking part of the combustion.

74. I saw wreaths of yellowish smoke coming out of the water by the ship's side. What would you expect that to come from?

Cordite.

75. Could you distinguish between the colour of a fire originating from UP ammunitition 4" ammunition in the open?

The colour of the flame would probably be the same in the two cases. 4" ammunition would be unlikely to give rise to a large amount of flame since unless stacked very close together explosion would not propagate from round to round in the open.

76. Do you consider a strong fire such as that from cordite would detonate a warhead?

There is very good evidence that it would detonate a warhead.

77. Will you give us your views on the effect of (a) background (b) distance on the appearance of the flames and smoke of a big explosion?

Flashes observed from different distances may appear slightly different colours. The appearance of smoke varies considerably in accordance to the background and also whether it is illuminated in front or behind. It might vary according to the intensity of the illumination, that is during the actual flash of an explosion and subsequently after the flash has disappeared.

78. Am I correct in understanding from your evidence that you regard the following as the colours of smoke arising from the various effects I am describing?

Detonation of TNT Black

Detonation of Cordite Grey

Explosion of Cordite Brownish Red

Yes, except that the colour of the cordite should be brownish red to yellow.

79. In answer to question No.65 you discussed the possibility of the effect being produced by the detonation of warheads and the ammunition stowed over them. Do you think the effect described, especially in view of its position could have been caused by the explosion of any or all of the after magazines of the "HOOD"?

The earlier question was coupled with the statement that streaks had been seen in the inverted cone of flame. These might also have been produced by explosion of the after magazines, individual cordite charges might be projected into the air not fully alight, but in any case there would be a large amount of projected debris.

80. Would you not have expected the effect, to have been much farther aft than that described?

I would.

81. I saw a colossal volume of brown smoke with a red glow all the way along the base of it. The red glow did not last very long. What would you expect this to be?

I should say that the red glow at the base of the smoke was the red smoke being illuminated by an intense fire from below. This would indicate a cordite fire.

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81. The following letter which has been received from Dr. G. Rotter, is included as an addition to his evidence.

"My general conclusion is that the sinking of the ship was due to the explosion of the 15 inch magazine. I do not think that any other of the material on board could have given rise to the sudden and vast explosion. Ignition of the 15 inch magazine may have been occasioned by a second hit to the ship or to a preliminary fire in the 4 inch magazine alongside. The arguments supporting the latter are that had the 15 inch magazine been ignited directly it would probably have blown up the ship at once. Preliminary ignition of the 4 inch magazine might account for the escape of flame up a shaft to the deck. It is obvious that if you have a quantity of cordite burning, the gasses must escape. These would only burn with a flame when they are surrounded by air. They would be under pressure and account for the blow lamp appearance of the flame on deck. The increasing intensity of such a fire would possibly burst through the partition between the 4 inch and 14 inch magazines, causing the explosion.

The reddish brown fumes make it practically certain that the main explosion was cordite. The other coloured smoke, e.g. black and white, referred to. May readily have been black; detonating T.N.T. or burning fuel oil; white partially detonated T.N.T. or steam.

While the explosion of the warheads might seriously damage the ship, I do not think that they would cause it to sink as rapidly as it did in view of the ship's transverse bulkheads."

- Page 402 -

EVIDENCE TAKEN AT DORLAND HOUSE, REGENT STREET, S.W.1. On 3rd SEPTEMBER, 1941.

COMMANDER REGINALD FOSTER PITT MATON, R.N., O.B.E.

The witness was cautioned in accordance with K.R. Chapter II.

81. Have you much experience in observing magazine and cordite explosions?

Yes, I have.

82. What would you expect the visual and aural effect to be to an observer outside the ship, of the explosion of one or more of the 4" magazines in the HOOD?

To a certain extent it depends on what degree of ignition is started in the ammunition; in other words, is it just one hot splinter or a fire of some sort?

83. Supposing it was caused by a large shell going off in the magazine?

I should expect probably almost instantaneous explosion of that magazine and if one magazine went off under such conditions, I should think the whole lot would be involved almost immediately.

84. Does the whole lot include the 15"?

Yes. It would generate sufficient pressure in those magazines to blow everything down.

Continuing his evidence, Commander Maton said - As a matter of conjecture I think that probably the first thing seem would be flame at a fairly high pressure through the easiest line of venting. That would probably be followed almost immediately by the opening up of that part of the ship with a dense cloud of dirty smoke.

85. What would the colour of the flame be?

Bright yellow flame.

86. What about noise?

I should think it would develop almost immediately – it might start with a rumble – if one was reasonably near one might hear the crump of the shell detonating and that would be followed immediately by an explosion noise – more of a roar.

87. If what is generally known as a small fire was started in one of the 4" magazines, what would you expect the effect to be?

If the fire is of a very short duration, I do not think that anything need necessarily happen. If, on the other hand, a cordite case was perforated by a hot shell fragment, the cordite would in that case would almost certainly be ignited. One cordite case being ignited need not necessarily have any effect on adjacent rounds, particularly if they are stowed in tubes.

88. You said the initial kick of flame appears the through the easiest line of venting?

Yes. On the other hand for the ignition of more than one magazine or if all the cordite was practically exposed it would all go off together.

89. Does the bulk of the effect of the explosion necessarily follow that easiest line of venting?

No.

90. So that you may get considerable effects nearly simultaneously in different places.

Yes.

91. You said that you considered it certain if any one of the 4" magazines exploded it would also involve the others. Does this remark apply to the relatively small upper 4" magazine between 280 and 296, observing it is surrounded by air spaces?

No, I don't think it is a certainty that the forward upper magazine would necessarily have that effect on the 15" magazines.

92. In the case of a main magazine explosion of such violence to disrupt the after end of the ship, where would you expect the main part of the phenomena to be apparent?

I should say that the main visual effect would be in the region of the 2 – 15" magazines, though you may get other effects coming up from other easyish means of venting.

93. Would you expect the turret roofs to be blown into the air?

There is a possibility.

94. Would you expect a gun house, compete with two guns, to be blown into the air as a unit?

I should not be surprised to see any portion of that part in the air. I could not say whether it would be possible for the turret and guns to appear together or not.

95. Is it a fact that the general effect of explosions or detonations always tends to go upwards rather than in other directions, imagining your explosive to be suspended in the air?

If the container is of equal strength all round the effect of the explosion or detonation will be equal all round.

96. If the cordite in the magazines which was ignited first was in the 4" magazine, other than the upper forward one, the gas pressure will depend upon the rate of burning of the cordite and the volume of space it has to expand in. It will therefore, destroy the weakest bulkheads or deck first and if the rate of growth of pressure is not too rapid it may spread through the ship under the armoured deck until it comes to the free-est venting place; so that one might expect a free venting of the flame through the engine room ventilator gratings or other easy passage for the gas. Do you agree?

Yes, but in view of the large air space available I am not certain that flame would travel that very long distance, unless there is sufficient gas generated to keep the flame going.

97. Do you consider it possible?

Yes.

98. One might expect, therefore, the first appearance of the explosion to be at some distance from the magazine, followed later by the main explosion which would appear in another position than the first, in the ship.

Yes, it is possible.

99. Have you had much experience in observing the detonation of T.N.T. or other high explosives in the open and between decks in ships?

Yes.

100. What structural effect would you expect to occur with the detonation or explosion of one or more warheads in H.M.S. HOOD?

A direct hit from a splinter will cause the warhead to detonate. If one of HOOD'S warheads detonates the one next to it horizontally would certainly detonate. I am not certain that the other two would necessarily go. The probability is that the whole structure in the neighbourhood of the detonation would be severely torn and twisted up.

101. What would you expect the visual and aural effect to be on an observer outside the ship of the detonation in the HOOD of one or more of her warheads?

I think the visual effect would probably be a very bright instantaneous flame, followed almost immediately by a large column of black smoke – assuming one had detonated. This would manifest itself through the damaged portions.

102. Would the flame of this detonation have any duration?

No, practically none.

103. What would it's (sic) colour be?

It is a bright yellow flame.

104. Could you distinguish it from cordite?

Yes. It would be a whiter flame than cordite.

105. The colour of the smoke would be?

If detonation takes place, black. Continuing his evidence Commander Maton stated that the sound would probably be a sharp crack. It would be much sharper than the noise of a cordite explosion.

106. You described cordite flame as being yellow and the T.N.T. flame lighter in colour. Would there be any red in either?

I am not a colour expert. It is possible there might be tinges of red – more likely in cordite than T.N.T.

107. What would you expect to happen to the armoured plates on the ships side as a result of the detonation of two warheads?

I would expect the 5" and 7" to be blown off, but the 12" is more doubtful.

108. You said you think it is possible that the lower 12" plate would not be blown off. Would you wish to modify your opinion if the ship was steaming at 28 knots and observing this plate is practically below the waterline?

If the 12" plate was badly displaced then I think there is a chance of it being pulled off.

109. Can you say whether it would be displaced or not?

I would rather not express an opinion.

110. Do you consider that a strong fire such as that from cordite would detonate a warhead?

A fire of short duration – no. If you maintained a fire round the warhead for sufficient time to boil up the T.N.T. you will work it up to detonation, but is going to take some little time to do that.

111. Assuming a very fierce fire, about how long will that take?

Assuming a very fierce fire it would be at least several minutes.

112. Would you expect any serious consequences to a ship as a result of a fire or fires in ready use lockers, 4" and U.P.?

Trials that we have done with ready use lockers of the light type have not shown any damage to the ship as a result of fire in it. As far as I remember, the ignition of a 4" charge in a light type locker only shattered the cartridge cases around it and ignited the wood. Subsequent to that the shells started cooking off as a result of the fire of the wood in the bottom of the locker, but that fire could have been dealt with in my mind, by anybody with a hose, before any shells started cooking off.

- Page 406 -

113. Have you experience of the effect on the ships structure of detonations and explosions?

Yes.

114. What do you think the effect on the ships structure would be of the detonation or explosion of one or more of the after 4" magazines?

If the explosion starts in one of the 4" magazines which were in contact it would certainly be transmitted to the remainder and so to the 15" magazines aft, with the result that it would completely open up the ship.

115. I was in a ship about 10 or 15 miles distant from the HOOD. It was quite a clear day with mirage. I saw a fire burning with a clear pinkish flame on the boat deck of the HOOD which increased in length but not in height. It was centred about the mainmast and might have spread as far aft as far aft as the after end of the boat deck and as far forward as the after funnel. I did not see much smoke with this fire and after it had been burning for 2 to 3 minutes a really terrific pillar of flame shot up from somewhere in the middle of the fire. This flame was like an inverted cone, reddish in colour with black and white streaks in it. It had a definite duration though a very short one. Immediately afterwards, the ship was enveloped in dense clouds of smoke which looked black to me. When the smoke disappeared nothing but the bows of the ship were left. I think the ship was hit just before this great explosion. What was the cause of this?

If there was H.E. on the upper deck and a certain number of light ammunition lockers perforated, you might have got the flame effect from them along the ship. The pillar of flame might reasonably be caused by the explosion of shell in the 4" magazine area. This might start a fairly large explosion of cordite in this magazine which would be transmitted to the rest of the magazines almost simultaneously and continue on to the 15" magazines. During this first part, very considerable venting would be necessary and it might appear that an easy line of venting would be through the engine room and decks above. During this period the explosion is transmitted to the 15" magazines which may well vent up to a certain extent, through the existing vent already formed. This would be followed by the final disruption of the ship. There would be a large volume of dark coloured smoke in the area above the engine room and also in the turret area.

116. Do you think that the detonation of two of HOOD'S warheads would have caused the effect I saw?

No, I do not.

117. Does your last reply take into account the fact that there was possibly a large amount of ready use ammunition on the decks above the torpedo tubes?

Yes. I do not think that the quantity of cordite there would be sufficient to cause the effect seen.

118. You spoke of a possible line of easy venting from the 4" magazine in a diagonally forward direction. Do you appreciate that the forecastle deck id the strength deck in this position in the ship?

No. I now think the results of the initial explosion might equally well have shown themselves at the after end of the boat deck.

119. With the gas pressure on the underside of the deck, would you expect them to vent initially through large ventilators, such as the engine room ventilators, prior to having to rupture the deck?

Yes, but the ventilators are enclosed in trunks of thin plating.

120. I saw an incandescent ball of fire about 100fy. In diameter at the top of the flame just described, rising rapidly. How would you account for this?

The possibility is that there might have been cases which had not got the oxygen available for combustion until they reached a height.

121. But I saw the ball of fire ascending.

I am afraid I cannot explain this.

122. Would your first answer apply equally to cordite as to T.N.T.?

Both should contain oxygen supplies.

123. Would you expect this ball of fire to be more likely produced by cordite than bt T.N.T.?

Possibly more likely to be cordite.

124. I was watching from a vessel about half a mile from HOOD'S starboard quarter. I saw a fire burning on the superstructure deck on the port side aft and I saw it spread rapidly to about the mainmast. It was reddish yellow in colour and there was a certain amount of smoke but no more than you would expect from an ordinary fire. About 2 salvoes later I glanced at HOOD again and I formed the impression that at that second, a hit arrived on board HOOD on the starboard side of the boat deck just before the mainmast. This impression was so distinct that I expected something to happen and about 2 seconds later, I saw an explosion take place from the same position in the ship. There was a very fierce upward rush of flame, the shape of a funnel – rather a thin funnel – and almost immediately the ship was enveloped in smoke from one end to the other. This explosion gave me the impression of a vast blow lamp, so much so, that I almost expected to hear the corresponding noise, but I did not. The colour of this explosion was rather lighter than the previous fire. I saw a considerable amount of debris in the air, including one large plate very high, but then I was busy and really saw no more. What did I see?

The impression I have got from this does rather indicate the venting of a magazine explosion.

125. Would you expect the detonation of warheads to produce the visible effect I have just described?

I don't think I should. I should expect the detonation of warheads to produce a more all round effect, and, I think, instantaneous.

126. Does that answer take into consideration the presence of the cordite in the ready use lockers above the torpedo tubes?

Yes.

127. If the warheads on the port side of the ship were detonated would you expect the starboard side of the ship to be immediately enveloped in smoke?

No.

128. If the warheads on the starboard side detonated would you expect witness to draw the explosion with a column of flame not enveloping the ships side?

No.

(The drawing referred to in the above question was Captain Leach's sketch of the explosion.)

129. I was half a mile away on the starboard quarter of HOOD. My impressions were as follows. I saw a flash and then there was a colossal volume of brown smoke with a red glow all the way along the base of it. The glow did not last very long. What would you put that down to?

The rapid burning or explosion of cordite.

130. In the event of a main magazine explosion in HOOD of sufficient violence to disrupt the after end of the ship, would you expect to feel any water-hammer effect on your own ship half a mile away.

Yes, I think you might.

- Page 409 -

The following letter which was received from Commander Reginald Foster Pitt Katon, O.B.E., R.N., dated 5th September, is included as an addition to his evidence.

130A

On thinking over my deductions as to what happened in HOOD as the result of the evidence of witnesses which you gave me, I am not certain whether I made my reasons clear.

I said that I did not think that the destruction of the ship was due to warheads being hit, my reasons for this are:-

(i) A direct hit or very near hit near the warheads would, I consider, cause their instant detonation. I gather that one witness said that there was a short delay between the hit and the visible effect.

(ii) The upward effect of a considerable quantity of flame of some duration does not indicate detonation of a warhead.

(iii) I should have expected to see some outward effect, very dark or black smoke, from the ships side in the position of the warheads. Admitted if the Port Warheads were hit this effect might not have been seen.

(iv) Taking the trial of the detonation of a high capacity H.E. bomb (I forget whether it was 1,000 or 2,000 lbs) on the superstructure of MARLBOROUGH as a standard, where the damage was not very extensive and assuming that the bomb was 1,000 lbs, I do not think that even if all four warheads, with a total of 2,000 lbs. were detonated, that the result could be so extensive as to rip the ship open to such an extent that she would break up and sink almost immediately.

Neither could their detonation have initiated the detonation of the warheads of the opposite side of the ship.

(v) It is also by no means certain that a warhead will detonate after having been hit by fragments. I have seen instances of this where considerable damage has been done to a war head with portions of the filling knocked out and also melted. Assuming that the upper or lower pair of warheads were detonated, I think it is very doubtful if they would have initiated detonation of the other pair. Equally they could not have started an explosion in the after magazines.

(vi) Assuming (a) that the ship had been hit in such a way as to open up access between the warheads and the ready use lockers above, (b) that a fire had been started in these lockers and (c) that the majority of this cordite found its way into the immediate vicinity of the warheads I do not think there would have been enough cordite available to have caused a fire big enough or of sufficient duration to boil up the warheads.

Taking all the above into consideration I do not think that the destruction of the ship is likely to have been caused by detonation of one or more of the warheads.

The witnesses descriptions of the visual effect, i.e. the initial venting, fit so closely, except as to the general dimensions, with those I have seen at various magazine venting trials. That there is little doubt in my own mind that the destruction of the ship was due to explosion in one or more of the magazines aft.

In the initial stage the cordite will be ignited and burn with increasing speed as pressure is generate. The time and speed of burning before explosion finally takes place will depend on the free air space available and also on the amount of venting space produced.

- Page 410 -

The actual line of venting must be open to conjecture, but would probably be through the hatches whether open or closed. Unless there was another hit which was not seen by any witness, it must be assumed that the hot mentioned by one witness was the one which initiated the explosion.

From his statement it would appear that this hit was rather far forward, but in view of his position, it is for consideration what degree of accuracy he could reasonably place on the hit.

Further, the path of a shell may have been deflected by internal obstructions in the ship. Such effects have been observed.

Again I do not know any details of the fuze in question, such as whether it will function on a thin deck, or its length of delay.

Taking the above into consideration I see no reason why this round may not have penetrated to the engine room and detonated near its after end and fragments entered the forward 4-inch magazine.

Assuming there were 4,000 rounds of 4-inch ammunition in the 4-inch magazines, there would be approximately 16 tons of cordite.

As a result of trials carried out in MARLBOROUGH I do not think that this quantity is likely to have completely disrupted the after end of the ship.

It is probable therefore that the explosion spread to the 15-inch magazines where there would be, on a basis of 400 rounds each, approximately 150 tons of cordite.

- Page 411 -

COMMANDER ROBERT FOLEY KNIGHT, R.N., (Retd.) O.B.E.,
Nominated by DIRECTOR OF NAVAL ORDNANCE

Witness was cautioned in accordance with K.R. Chapter 11.

131. Have you had much experience in observing the detonation of T.N.T. and other high explosives in the open and between decks in ships?

Yes, I have had considerable experience.

132. Would you expect the explosion of a large shell near the HOOD'S torpedo tubes to detonate one or more of the warheads?

Yes, if it were very close.

133. Having seen the drawing of the stowage of torpedoes, do you think that the detonation of one would be liable to cause detonation in any of the other three?

I think it would cause explosion in probably the one alongside it, but I would not like to say there would be an actual detonation. It would burn to a violent explosion. I should say the warheads above or below it would not be affected apart from being broken up.

134. Have you experience on the effect on ships structure of detonations and explosions?

Yes.

135. That being the case will you tell us what would be the effect of one of HOOD'S warheads detonating in its mantlet?

The answer would be surmise because the only torpedo warheads I have seen detonated have been above water in the open, and the effect of them being enclosed in a mantlet would enhance the effect. The first thing would be that the doors would be blown off and after that the mantlet would be disintegrated – most of the effect being upwards and then inboard. The armour on the ship's side would probably be started; damage would also be done to the shelter deck, but not very extensive. The ship's side above the forecastle deck would be damaged and probably plates blown out.

136. Do you think any of the armour plates would be dislodged and fall over the side?

No. I think the bolts would probably be started but not actually dislodged.

137. What do you think the visual and aural effect would be to an observer outside the ship of the detonation in the HOOD of one or more of her warheads?

A rather darkish red flash, followed by black smoke.

138. Where would this manifest itself?

Immediately above the tubes in the shelter or boat deck, also through the doors of the mantlet in the case of the lower warhead going off. In the event o the other warheads going off, it would only be seen from the shelter deck. I should not, in this case, expect the armoured doors to be blown open and the effect would be a bit more visible through the shelter deck.

139 (a) What noise would you expect to hear outside the ship, and (b) would there be much difference between the sound of an explosion and detonation?

(a) Just 5 cables away – a sharp crack of the detonation. (b) to the inexperienced observer, none whatsoever.

140. How high would you expect the flames to shoot through the shelter deck?

I do not consider any flames in the ordinary sense would be seen, merely an instantaneous flash, coming out of the shelter deck, probably 30ft. That is on the assumption that we are speaking of a warhead that detonated. It if exploded the effect would be less and the flash would be less instantaneous, depending on the degree of the explosion.

141. If the ship was steaming at 28 knots do you think the loosening of the armour plates you refer to would be likely to cause them to drop off owing to the rush of water past the ship's side?

If the ship were rolling at all, sufficient to submerge half of the plate and the plate was opened out the fore end it probably would be torn off.

142. Do you think the 7" belt would be affected?

No.

143. Do you think the 12" belt would be affected?

No.

144. Would you tell is what damage you would anticipate if two warheads detonated?

The effect would be very greatly enhanced. In the case of two warheads detonating the ships side nearest the warheads would be blown out as well and the damage to the boat deck above the mantlet compartment would be very extensive.

145. What about the upper deck itself and the ship's side below it?

The upper deck would probably be bulged down and the ships side plates started down to and including the 7" belt.

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146. Would you expect a fracture of the upper deck?

It might possibly be holed but not to a great extent.

147. What about the armoured deck?

I don't think that would be affected.

148. How high do you think the flames of this detonation would go?

I do not think there would be any difference between one or two warheads but as the boat deck and ships side would be more opened out, the flash would be more apparent. I would like to say that unless an observer was concentrating on that particular part of the ship or at least the after part of the ship, I do not think he would see any flash at all. Smoke, yes.

149. You have described what you anticipate would be the damage caused by 1000lbs. Of T.N.T. detonating. Do you remember seeing the 250lb. S.A.P. bomb in the Forecastle deck of the MARLBOROUGH, this bomb containing under 50lbs of T.N.T.? If so, will you explain why, in this case, the damage was so much more extensive than you have nor described to us for 1000lbs.

The answer is that the structure in the MARLBOROUGH was a great deal lighter than this particular case we are considering.

150. The mantlet box round the tubes in HOOD is provided to withstand and keep out splinters. Although the plating is very thick the structure is not very strong and therefore I do not see the justification for your statement that the structure in MARLBOROUGH was so much weaker than that in HOOD. Will you therefore say why you think the structure in MARLBOROUGH is so much weaker than that HOOD?

From my recollection the forecastle of the MARLBOROUGH is about 25/30 lbs. plating; that is what I should term light scantlings. Further I based my answer on the effect of the torpedo warheads on trials carried out in Job No. 74 when 3 – 750 lb. Warheads were detonated simultaneously.

151. Will you please make a comparison of the damage you have described for HOOD with that caused by the 250 lb. S.A.P. bomb containing 47 lbs. of T.N.T. which was detonated immediately under the strength deck in Job No. 74 and in the static 5.25" casemate, when the upper strength deck was blown up in spite of elaborate venting arrangements, to such an extent that it is no longer fulfilled its function as a strength deck.

My recollection of that bomb was that the damage was not very extensive and the only explanation I can give for the difference is the fact that the blast and splinter effect from a semi armour piercing bomb is much greater than the unenclosed head of a torpedo warhead.

152. Would you expect much smoke from the detonation of two warheads and if so. What would be its colour?

The colour would be black, similar to the smoke of the 1080 lb. Light cased bomb in MARLBOROUGH.

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153. On the shelter deck over the position of the torpedo tubes in HOOD is stowed a considerable quantity of 4" ready use ammunition and also some U.P. ammunition. There was a fire on this deck and possibly amongst the ammunition at the time when the major explosion occurred in the ship. If this major explosion was caused by the detonation of the 2 warheads to which we have just been referring, what would you expect would be the visual effect to an observer outside the ship, due the presence of this ammunition?

It is conceivable that some of the charges that we already ignited would continue to burn in the air and give the appearance of a firework effect.

154. You stated that if two heads detonated you would expect the 5" armour of the mantlet to be blown away. Would you expect the flame and smoke as seem from an observer on that side of the ship, to appear to be coming out below the level of the boat deck as well as above it – through the hole which had been occupied by the armour?

The flash would appear to come out from both places.

155. Would there be smoke below the level of the boat deck from that hole?

Yes, probably down to the water level.

156. Have you had much experience in observing magazine and cordite explosions?

A good deal of experience of magazine venting. A limited experience of magazine explosions.

157. What do you think would be the effect of a 15" or 8" shell detonating in one of HOOD'S after 4" magazines?

A 15" shell bursting in one of the 6 – 4" magazines will ignite the cordite in the charges in that magazine which will disintegrate the weaker bulkheads and decks; the effect of the explosion will be extended to the neighbouring magazines with the result that in all probability the bottom of the ship would be blown out.

158. Do you mean that the 4" ammunition itself could cause the bottom of the ship to be blown out?

Yes.

159. Do you think the explosion would extend to the 15" magazines?

Yes, in all probability.

160. In the event of a shell detonating outside near the foremost upper magazine of the after group do you consider it possible that some or all of the charges contained in this magazine could explode or become ignited, without necessarily conveying the explosion to adjacent magazines?

The answer to the first part is that some of the charges will be ignited by the shell splinters, but the fact whether the explosion extends to other magazines depends on which direction the explosion vents.

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161. Would a shell detonating in one of the compartments adjacent to the other 4" magazines cause an explosion in that magazine?

I should say that the odds are about even. Some charges will undoubtedly be set off by splinters and if the magazine bulkhead in communication with another magazine gives way, it might provide sufficient expansion space to prevent a major explosion.

162. What would be the effect of a shell detonating in one of the 15" magazines?

A major explosion would take place and the ship's structure in the area of the magazine will be wrecked.

163. What would be the effect of a 15" shell detonating in a compartment adjacent to one of the 15" magazines?

If it is sufficiently close for a splinter or splinters to enter the magazine and ignite the cordite a major explosion will occur.

164. Do you consider that a strong fire, such as that from cordite would detonate or explode a warhead?

I have no experience of this but my opinion is that the warhead would not detonate; it might burn to a mild explosion.

165. Would you expect any serious consequences to a ship as a result of fire or fires in ready use lockers – 4" fixed and U.P.?

No.

166. What would you expect the visual and aural effect to be to an observer outside the ship of the explosion of the after magazines in HOOD?

To an untrained observer I do not think the fact that the 4" went off one thousandth of a second before the 15" would be apparent. The aural effect resulting would be something between a thunder clap and rumbling noise, which is rather hard to describe. It will be quite easy to differentiate from the detonation or explosion of a shell – it will be much more prolonged. The visual effect would probably be a spurt of flame from "X" and "Y" gun houses, embarkation hatches and hatches on the shelter deck over the 4" magazines. This will be followed by very large volumes of smoke, probably black to start with. In connection with the colour of the smoke there is really little indication as one trial that we had in MARLBOROUGH gave off black smoke and another grey, both coming from the same source.

167. Would you expect those flames to be instantaneous or to have any duration?

Appreciable duration.

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168. Would you expect them to reach any height?

Masthead high, as if they were coming out under great pressure.

169. What would the colour of the flame be?

Yellow.

170. Were you present at the magazine venting trials in MARLBOROUGH which were carried out in July/August 1931?

Yes.

171. The report by H.M.S. EXCELLENT says that "in the first 16" trial just over half a ton or cordite was consumed. The explosion was heard as a faint rumbling, followed about one second later by jets of smoke from the mizzles of the guns, and about half a second later high pressure smoke was issuing from all openings in "B" gunhouse, including the turret handing room etc. No actual flame was visible. In the second trial when slightly more cordite was consumed the effect as viewed by observers was similar. Gases first issued from the manhole in the turret roof and then from the muzzles and gun ports as thin jets of smoke which were quickly transformed into clouds which were emitted at high pressure."

Do you consider that this is a true and accurate description of what occurred especially in so far as the main optical effect appeared to have its centre almost vertically over the magazines concerned?

Yes.

172. If now instead of half a ton of cordite the magazine contained say 80 tons, would you think it less likely or more likely that the optical effect would appear to have its centre vertically over the magazine itself?

In the case of the MARLBOROUGH trial there was not a major explosion and the products of combustion vented to the turret. In the present case that is being considered, the magazine does not vent but explodes and I consider that hatches leading to the weather deck will be blown up simultaneously, with more extensive damage to the interior of the ship, owing to the fact that a great deal higher pressure will be generated.

173. Would you in fact anticipate that with the very much heavier explosion the apparent seat of the explosion would be moved some appreciable distance from the magazine area?

No. I think that the products of the explosion will in any case come up through the turret, embarkation and other hatches.

174. Are you familiar with the general details of the 15" mountings as in HOOD?

General details, yes.

175. Do you think it possible or probable for an explosion of one of her 15" magazines to blow into the air a 15" gunhouse with its roof and sides intact but not including any appreciable part of the working chamber or other revolving structure and yet have the two guns apparently in their correct position in the gunhouse whilst in the air?

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175. I would say it is not impossible but I think most improbable although the roof of the gunhouse may well have been blown off.

176. In the event of a major violent explosion of a main magazine in HOOD would you expect any appreciable waterhammer effect to be apparent to a capital ship 4 cables away?

Yes, I should expect a slight waterhammer effect. This is based on my experience when the VANGUARD went up and I was in the next ship to her about 3 cables away.

177. Would you expect to see single guns in the air?

No.

178. I was 10 or 15 miles from the HOOD on the starboard quarter and I saw a fire burning on her boat deck round about the maimast. I could not tell exactly where it was but it was definitely abaft the after funnel and before "X" turret. It burned with a clear flame and I could see very little smoke. After this fire had been burning for about 3 minutes I saw a streak of flame shoot vertically up from some part of this fire, several times the height of her mainmast and shaped like an inverted cone. This flame had a definite duration though a short one. Dark coloured smoke quickly spread out at the top in a mushroom shape and immediately enveloped the whole ship. When the smoke had cleared all that was left were the bows of the HOOD sticking up at a steep angle and these sunk very quickly. What caused this happening?

I don't think that the fire that was first seen had any direct connection with the explosion. It must have been a magazine explosion.

179. Would the detonation or explosion of any number of the HOOD'S warheads have given a similar effect?

No. In any case I cannot imagine that warheads would be sufficient to blow the after part of the ship off so that only the bows were seen after the flash.

180. In the reply to the last question regarding warheads – os it possible that the existence of large quantities of burning ready use cordite on the weather deck may have influenced the appearance of the explosion at a distance?

No, quite impossible.

181. If in addition to what you have just herd described you saw an incandescent ball of fire rising rapidly through the flame, the ball being about 100 ft. diameter, what would you put this down to?

As this incandescent ball was seen rising in the flame, I can give no explanation. I have seem a sphere of flame resulting from a warhead detonation, but this was stationary and only visible for say a fraction of a second.

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182. How do you account for the white blob in the cinema photograph of the 250 lb. Bomb burst below decks by "Q" turret in MARLBOROUGH and which was apparently visible for 1.10 secs.?

It might be smoke or incandescence. I cannot recall whether or not I saw it and I cannot explain it.

183. I was also watching HOOD from half a mile away on the starboard quarter and I also saw a fire spreading rapidly forward on the boat deck. Then while I was looking I formed the impression that something had arrived on aboard HOOD, that there was in fact a hit in a position just before the mainmast slightly to starboard. The impression was not very definite, but sufficiently definite to make me look at the HOOD for a further period. I expected to see something, and between one and two seconds after, an explosion took place which appeared to me to come from just before the mainmast near the midship line. There was a very fierce upward rush of flame, the shape of a funnel – rather like a thin funnel – and almost instantaneously the ship was enveloped in smoke from one end to the other. The explosion gave me the impression of a vast blow lamp and I almost expected to hear the corresponding noise, but I heard nothing. The colour of the explosion was lighter than the previous fire and I saw considerable quantities of debris in the air afterwards. Then I had other things to attend to and saw no more. The last I saw was the ship covered in smoke. What do you think was the cause of the explosion?

I should say it was a 4" magazine; owing to the fact that the observer was fine on the starboard quarter he may have been mistaken as to the exact origin of this upward spout of flame on the fore and aft line. Would you say definitely that was the result of a cordite explosion or T.N.T.?

I should consider it much more probable to be a cordite explosion.

185. You have previously told us that if the 4" magazine exploded, it is most probable that "X" and "Y" would also have exploded. Even allowing that the witness was mistaken and the explosion took place say on the after end of the boat deck instead of before the mainmast, would you expect the appearance of the explosion of "X" and "Y" magazines also to come up at the after end of the boat deck?

The explanation as I see it for that phenomena is the fact that the first results of the 4" magazine explosion was upwards and extended to the 15" magazines which blew the bottom out of the ship. I can see the possibility of an explosion of 4" magazines first venting to a line of hatches to the weather deck producing the column of flame which was described and after a very short interval of time the explosion extending of the 15" magazines which did the vital damage. Another possibility is that the first explosion of the 4" magazines vented into the engine room and thence to the weather deck producing the funnel of flame.

186. From your experience as an observer of explosions, so you consider that any one observer can have a clear and complete impression of all the phenomena which may be present and visible in a big explosion of this sort?

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No, it is most improbable. Reports from two or three different observers would show considerable variance.

187. Would that variance extend to a considerable difference in the location or position of where these observers think the centre or major portion of the explosion was?

I doubt it. I think the first major event seen by that observer would be more or less accurately recorded.

188. If this observer had actually seen warheads on the port side blow up, would you expect him to immediately see the starboard side of the ship enveloped in smoke from detonation of warheads on the port side?

No. The pall of smoke would never extend far enough over the starboard side at that speed to appear to emanate from the starboard side.

189. Looking at this sketch which was made by Captain Leach, do you consider that he would have made the sketch if the explosion had been in the starboard warheads, observing that there is no flash or damage down over the ship's side at all.

No.

190. Do you think the witness would have drawn "X" and "Y" turrets intact if there had been an explosion in "X" or "Y" magazines?

It is a question of relative time again, because he may have pictured the event whilst the explosion was taking place, before the outward and visual signs of the explosion in "X" and "Y" magazines was apparent.

191. I was an observer on the starboard quarter half a mile away. All I saw was a flash and then a colossal volume of brown smoke with a red glow all round the base of it. The red glow did not last for very long. What would you put this down to?

I can give no explanation of that. It might be due to a cordite fire, but the colour of the flash that was observed is a darker red than normal cordite fires of my experience. The smoke well may have been the result of cordite of high explosive exploding.

192. You say the colour of the glow was too dark a red than normal for cordite. Was it approaching the red normal with T.N.T.?

Yes.

193. I was on the starboard quarter half a mile away and was told HOOD had gone up and a particular feature that I noticed was that smoke which was dark thick yellow was coming up in wreaths from under the water. What would you expect this to come from?

I am not prepared to say whether that would be the result of an high explosive or cordite explosion, but probably the latter.

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The following letter was received from Commander Robert Foley Knight, R.N., date 5th September, is included as an addition to his evidence.

193A There is one point I should like to elaborate and one subject I ought to have brought up at the time.

2. Warhead's detonation. A useful parallel of the damage cause by an "unconfined" charge of H.E. is to be found in the case of the two 2000 lb. Light case bombs (1080 lbs. T.N.T./C.E.) fired in H.M.S. MARLBOROUGH. Both bombs were judged complete detonation whereas it is unlikely that this occurred in the case in discussion. Extracts from H.M.S. EXCELLENT'S report 9E.030/5/1 of May, 1941.)

Para 5 (c)

"…..the effect on unarmoured structure of a warship is confined to a sphere of 20 feet radius, struck about the centre of the bomb. Any structure lying within this sphere will be either blown away, completely destroyed, rent or bulged according to its strength and resistance."

Para 8 (b)
"The results obtained with this large amount of efficient explosive detonated in positions most favourable to the bomb are not such as would cause the partial or temporary disablement or destruction of a warship"

3.- Venting Q.F. magazines. No trial has ever been done to see the result of igniting a charge in a Q.F. magazine and proposals were put up by H.M.S. EXCELLENT to investigate the matter just before the war and approval for the trials was given in G.05540/39 of 16th November, 1939. However, this was cancelled in Admiralty letter D.06742/40 of 9th August, 1940. In consequence although we have information about B.L. magazines, no one can say what is the effect of the ignition of one or more charges in a Q.F. magazine. It is possible that a prepared vent for the cordite gases might prevent a major explosion, and if this is so of course, it will raise an important question as there are so many ships involved. It seem to me this matter has a direct bearing on your enquiry and that I am taking this opportunity of bringing it forward.

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MR. DUDLEY EDWIN JAMES OFFORD, R.C.N.C. recalled.

4th September, 1941

The witness was cautioned in accordance with K.R. Chapter 11.

194. Can you give us any statistics regarding the properties of German 15" Shell? If so, please give us the relevant information.

The calibre of BISMARCK's main armament was 38cm.m i.e. practically 15". The shell weighs 1600lbs. The British 15" as used by HOOD weighs 1920 lbs. The German shell is therefore, about 15%lighter than the British. There are 2 sets of data regarding the ballistics of BISMARCK's guns. One set gives a muzzle velocity of 2721 f.s. with a shell of 6 c.r.h. The second set gives a muzzle velocity of 3150 f.s. with a shell of 8 c.r.h. HOOD's 15" had a muzzle velocity of 2459 f.s. with a shell of 4 c.r.h. The above information has been supplied to the Director of Naval Construction on official papers by the Director of Naval Ordnance.

195. Can you tell us the probable angle of descent and velocity of the shell at ranges of 20,000, 18,000 and 16,000 yards?

Yes, they are as follows. (This information is also supplied by D.N.O. on official papers to D.N.C.)

Range Case A. Muz. Vel. 2721 f.s. Case B. Muz. Vel. 3150 f.s
Remaining Velocity. Angle of descent Remaining Velocity Angle of descent.
15,000 yards. 1925 f.s 9.1° 2305 f.s. 6.4°
16,000 yards 1884 f.s. 10° 2259 f.s. 7°
18,000 yards 1797 f.s. 12.2° 2162 f.s. 8.5°
20,000 yards 1718 f.s. 14.5° 2070 f.s. 10°

Assuming an angle of descent of 5 to 10 degrees at 16,500 yds. Remaining velocity to perforate 13" "C" belt at 50 degrees inclination is about 2250 f.s. This spot falls very close to the immunity curve for case B, i.e. muzzle velocity equal to 3150 f.s.

At 16,500 yds. Range, remaining velocity in case A, which is 1,900 f.s. indicates that the low muzzle velocity of case A gun would not be sufficient to enable the shell of defeat 13" "C" belt at 16,500 yds. And 50° inclination.

196. Bearing in mind the foregoing information can you tell us how BISMARCK's 15" shell would have behaved against HOOD's protection at a range of 16,500 yards, assuming the angle of inclination from the fore and aft line to be about 50° ?

HOOD's main belt was 12" cemented armour behind which was two separate layers of ¾ " special quality steel and on the slope of the main or protective deck, two more thicknesses of 1" special quality steel. This combination I consider approximately equivalent to 13" of cemented armour, including an allowance for the slope of the main belt. If the muzzle velocity was 3150 f.s. BISMARCK's shell would defeat 14" of cemented armour at 16,500 yards and 50° inclination. Thus HOOD's main belt and the plating behind could be defeated and with a very considerable delay a shell could enter and burst in, or alternatively burst close to, any of the main or 4" magazines.

If, however, the BISMARCK's guns had a muzzle velocity of 2721 f.s. at 16,500 yards range and 50° inclination, her shell would defeat only 10 ½

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Cemented armour. Thus no such shell could defeat HOOD'S main belt. It could, however, defeat her 7" belt. It would then, however, in general have had to defeat also the main and lower decks before it could reach the magazines. At 16,500 yards such a shell would not defeat this thickness after passing through 7" cemented armour. Thus, in general, with the lower muzzle velocity, no shell could burst in or near, any of HOOD'S magazines. I have said in general, because the question at once arises "Is there a chink in the protection?" D.N.C. has caused a skeleton model of HOOD to be prepared on which is indicated the thicknesses of armour, decks, bulkheads etc. For use with this model is a pointer which is set to an inclination of 50° and to an angle of descent of 20°, and also indicates fuse delays. An angle of descent of 20° is somewhat more than that due to the range with a gun of the ballistics assumed, but was chosen to allow, in the favour of the shell, for a small roll or heel of the target ship. By searching with the pointer on the model one can find a small area in which a shell can enter and pass over the top of the 12" belt and yet get in under the flat portion of the protective main deck. It can with a suitable delay, burst in or very close to the upper forward magazine of the after 4" group. The delay would need to be much longer than the average performance of British fuses. Also shells greatly tend to turn towards the plate normal in perforating side armour, and although this would make the defeat of the subsequent protection less likely. I have ignored the possibility of such a turn. Thus, it would be a very lucky shell which exploded in or near any of HOOD'S after magazines if the BISMARCK'S guns had a muzzle velocity of about 2721 f.s. I would, in fact say, that it is not impossible, but highly improbable.

There is another alternative and this applies to both muzzle velocities. A shell could fall short of the ship and enter the ship below the armoured belt. Once again, taking 20° angle of descent to allow for a possible roll or heel of the HOOD, the fuse delay would need to be about 75 feet to reach a main magazine or about 55 feet to reach a 4" magazine. A study of a section of the ship in the after magazine area, shows, however, that there

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Is only a comparatively small zone in which such ‘shorts' could fall to burst in or close to magazines.

Summing up, therefore, if BISMARCK'S guns had a muzzle velocity of about 3150 f.s. they could defeat HOOD'S main protection and shell could burst in or close to any of her magazines. If, however, BISMARCK'S guns had a muzzle velocity of about 2721 f.s. the main protection could not be defeated but there were two small zones in which shell could fall, and by avoiding the main protection and if the fuse delay was favourable, burst in or close to the 4" or 15" magazines. It is my opinion, however, that it would be an extremely lucky shell that did so.

197. You have described shell piercing the side armour. What about a plunging shot that come in over the top of the side protection?

The side protection runs up to the forecastle deck. Even if the shell succeeded in perforating this deck its trajectory at the range in question would take it clear over the top of the magazine.

198. That is assuming there is not deflection of the shell after perforating the forecastle deck?

Quite so, but the more general deflection in this case would be upwards rather than downwards as at big angles of incidence tendency is for the shell to ricochet from the deck.

199. You refer to two small zones of danger. Can you indicate the size of these two zones?

Only very roughly. Concerning the shell which comes in over the top of the 12" belt and under the flat portion of the main protection deck, the zone is about 18" deep extending from bulkhead 259 to bulkhead 280. Concerning the shell which comes in under the main belt, my knowledge of the under water path is so limited that I would not care to make any definite statement, but the fall of shot would need to be I think in a zone a few feet wide and of a length approximately the same as the total length of the magazine group.

200. At what muzzle velocity would BISMARCK'S shell just defeat the 12" belt and plate behind and so be free to reach the HOOD'S magazine under the range and inclinations in question?

The muzzle velocity would be about 3050 f.s.

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201. In view of the age of the ship and the alternating stresses that the armour may have been subjected to, is it possible that the efficiency of the armour may have been affected by fatigue?

The side armour is slabs of metal bolted on to the ship's side. It is not subjected to any stresses on account of the vibration or working of the ship in a sea way. There would, therefore, be no deterioration in the side armour due to fatigue, or other cause, with the possible exception of a slight reduction in thickness due to rusting. There is some confirmation of this from the fact that armour removed from over age battleships has been used or proof purposes at Shoeburyness and the actual performance was quite up to specification standard laid down when they were new.

The deck protection, is however subjected to the alternating stresses with the ship at sea, but the magnitude of this is in general, well below the limit at which fatigue sets in. During the bombing trials against H.M.S. MARLBOROUGH - a ship which was then over 15 years old, including 4 years of very strenuous war service – it was suspected that her strength deck may have deteriorated slightly due to the cause referred to in the question. Samples were cut out and subjected to detailed laboratory tests and microstructure analysis. The material was judged to be up to the full specification standard. More recently similar tests have been made on the strength deck of BELFAST in the region of the fracture of that ship. Again the results show the material to be up to full standard.

202. Would you expect to find any loss of strength or efficiency in the light bulkheads of the ship due to age or any other cause?

The whole ship's structure, including armour, strength deck and bulkheads, is subject to deterioration due to rusting. Under any set of conditions the rusting depends upon the time and not the thickness of the plate, and therefore rusting which is negligible in side armour or a thick strength deck becomes important in the relatively thin plating of some of the structural bulkheads. Moreover in many places the inaccessibility of the lower portions of the bulkheads means that their rate of rusting is above that of the more accessible structure, such as strength decks.

203. Was it not a fact that a shell did enter H.M.S. PRINCE OF WALES under the water below her armour belt? Could you tell us more about this?

Yes. One of BISMARCK'S 15" shell entered the outer bottom of the PRINCE OF WALES just at the upper edge of her bilge keel. It perforated [continued on next page]

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The outer bottom and both bulkheads of her sandwich bulge and was brought to rest in contact with the protective bulkhead which consists of 2 thicknesses of 30 lbs. or 35 lbs. plating. The damage within the ship showed that the shell was still stable, i.e. travelling with it's (sic) axis coincident with its trajectory, but the latter was rising slightly towards the end of the travel. The total travel from the time when this shell struck the water until it was brought to rest within the ship was about 90 ft. The shell was "blind." Subsequent examination as (sic) shown that the fuse had functioned but the powder train between the fuse and the filling had "gone out." In my view it is most probable that if this shell was going to detonate it would have done so before it reached the ship, assuming that the German fuse, like the British, functions in water.

204. You have explained to us the possibilities of a 15" shell exploding actually in any of HOOD's after magazines. Will you now tell us the possibilities in a shell bursting in a compartment adjacent to the magazines, with sufficient violence to penetrate the bulkheads into the magazine causing them to explode or detonate?

The splinter zone of a shell which bursts in flight is not symmetrically disposed round the shell. It takes the form of a cone with its apex at the shell and opening out ahead of the shell in its line of flight. Thus for a burst in a position there is a limited zone in which splinter damage is likely to occur. Many trials have been carried out in an attempt to provide data regarding the perforating power of shell splinters. The answers are almost as numerous as the trials. I prefer, therefore, to base my judgment in this matter more on present war experience than on experimental results. As a result of this experience I consider that splinters from German 15" shell are unlikely to pass through more than two thicknesses of bulkheads or decks of protective thickness, as ¾ " or more, with sufficient remaining velocity to cause ignition of cordite stowed as in HOODS 4" or 15" magazines. Thus a shell bursting in a particular part of the after Engine Room could send splinters into the upper forward 4" magazine or possibly into the one below it. I do not consider splinters from such a burst would enter the lower forward magazines. In the particular case of a burst in the Engine Room there are probably so many fittings, pipes, spare

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Gear etc. on this bulkhead, that only a relatively small percentage of the total number of splinters are likely to perforate to the magazine.

A shell which entered and burst in the Central Store or the shaft passage abreast of the 4" magazines, may send splinters into those magazines with sufficient violence to cause explosion. Abreast "X" and "Y" magazines a shell would need to burst in the compartment actually adjacent to the main longitudinal bulkhead of the magazine in order that its splinters would enter the magazine with sufficient violence to cause an explosion.

205. Would a shell of initial velocity of 2721 f.s. be able to burst in any of the compartments you have named, under the conditions we are discussing?

Yes. As regards the shell bursting in the Engine Room provided it enters within the narrow zone to which I have previously referred. A shell cannot, however, pass through this zone and burst in the Central Store or Turbo-Generator room. Although it could burst in the compartments above, in this case I consider the splinters would not perforate into the 4" magazines with sufficient violence to cause an explosion. Considering shell which entered the ship under the armour belt, they may send splinters into the 4" magazines and so cause explosion, if they burst in the after end of the Engine Room, in the inner shaft passage abreast the 4" magazines, or in the Oil Fuel filling spaces or Oil Fuel Tanks, Stores, etc. abreast "X" and "Y" magazines. The shell will, however, in general need to be deflected upwards from its original trajectory to enter these compartments.

206. For shell to penetrate underneath the armour belt, they would have to hit the water some distance from the ship's side. Would a fuse of normal delay action burst before such a shell reached the Central Stores or compartments in a similar horizontal plane that you have just mentioned?

Yes I think it would, provided it functioned on first impact with the water. The most favourable case appears to require a delay of about 70 ft. of which about half if through water, when I anticipate the shell would be losing velocity fairly rapidly.

207. Is it possible that if a shell was deflected from its normal path the chances of it penetrating to a vital part of the ship would be increased rather than diminished?

Yes, but in the early stage of the penetration into the ship, the shell will have a fairly high velocity and with a main armament shell it will need a very substantial obstruction to cause any appreciable deflection in its

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Path. Such a heavy obstruction is just as likely to decrease the shell's perforating power by reason of the velocity which it takes out of the shell, as it is to increase its perforating power by deflecting it so that it meets the next line of penetration at a favourable angle. Once the shell has perforated through all the main resistance offered by the various protective schemes of the ship, it will be more susceptible to deflection, and deflection towards any particular point is just as likely to happen as deflection away from it.

208. Am I to understand that it is possible to increase the shell's possibility of reaching a vital area by deflecting it on some obstruction?

Yes.

Evidence of Mr. Dudley Edwin James Offord, R.C.N.C. Recalled – 5th September, 1941.

209. Have you any information as regards the delay action of German fuses which hit our ships during this war? If so, will you tell us something about them.

Yes. In the action of the River Plate the British Ships were attacked by the GRAF SPEE which carried 11" guns. The AJAX received one hit fired from about 8,600 yards. The travel within the ship from the time of first hitting to position of burst , was 43 ft. This shell met what one might term fairly heavy obstruction observing that the target was a cruiser. The EXETER received 7 hits, one shell did not explode. 4 burst on impact and the other 2 gave delays of 65 and 70 ft. respectively. The range was about 10,700 yards. Both shell met with average obstruction for an unarmoured cruiser.

In her action with SCHARNHORST also firing 11" guns RENOWN received 2 hits from a range of about 18,000 yards. The first passed completely through the ship at the after end; travel within the ship was 26ft. It is not known whether the shell exploded after passing out of the ship. The second hit was on the foremast and there is no report as to whether the shell exploded or not.

BERWICK was in action with a German 8" cruiser and received 4 hits from about 10,000 yards, The first one passed completely through the ship, a distance of 15' 6", met with fairly heavy obstruction but did not explode [here several words are missing from my photocopy] second one travelled ??? within the ship but was

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"blind". The third travelled 56 ft. before exploding having encountered medium obstruction. The last one burst very soon after impact with 4 ½ " cemented armour.

In her action with BISMARCK AND PRINZ EUGEN subsequent to the sinking of HOOD, H.M.S PRINCE OF WALES received 7 hits. 3 of them were with 15" shell. The first travelled 24 ft. within the ship and then passed out the other side. It is not known whether it subsequently exploded. This shell met with only light obstruction. The second one travelled 30 ft. before exploding. It met with very light obstruction. The third one travelled about 80 ft. through the water before striking the ship. It then travelled 12 ft. within the ship before coming to rest, but did not explode. PRINCE OF WALES received 4 hits with 8" shell. The first travelled 8 ½ ft. through the ship and it is not known whether it subsequently exploded. The second travelled 72 ft. within the ship and was 'blind.' The third travelled 11 ft. before exploding, having met with rather severe obstruction for an 8" shell. The fourth burst on impact, having some in contact with the edge of the armour deck over the steering gear.

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EVIDENCE OF CAPTAIN ROBERT COLLETT WOOLLERTON, O.B.E., R.N. D.N.O. DEPARTMENT, BATH.

5th September, 1941.

The witness was cautioned in accordance with K.R. Chapter 11.

210. Are you an expert in the characteristics and properties of fuses?

Yes.

211. We have been given two possible initial velocities of the 15" projectile of the BISMARCK, i.e. 2721 and 3150 f.s. Do you know how either of these were arrived at?

The figure 2721 was taken from a secret report sent to the Admiralty by the Russian Intelligence. This figure is not considered to be entirely reliable as other figures given in the same message have been shown to be incorrect. The higher figure was an outside estimation by D.N.O.'S Ballistic Department of what was considered possible.

212. Do you think a muzzle velocity of 3150 is the upper limit?

I am not competent to answer that, but I will give the Board a statement after I return to Bath.

213. Have you any information concerning the perforating power of the shell as fired by BISMARC, that is to say if calculations of its perforating power were made by the same formally (sic) as used for British 15" shell, do you think the answers would be approximately correct?

D.N.O. has no definite information about the qualities of German shell, but a shell is now under critical examination on which the report has not yet been received. This critical examination should disclose any superior qualities that may exist in the German shell, but in D.N.O.'s opinion it is unlikely that such qualities will be found.

214. Is much known of the properties of German fuses for heavy shell compared to ours?

It is known that during the last war German armour piercing shell had a delay action of about .05 sec. Which would give a delay in feet of about 50 – 60 ft. at a remaining velocity of 1800 f.s., after passing through 6" of armour. Examination of recent German fired fuses shows that present German delays are probably of the same order. The actual delay cannot be accurately determined as no unfired German fuses have been available.

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215. Does a fuse necessarily function when a shell hits the water?

British base fused shell usually function on hitting the water and action experience in this war has shown that German shell usually do so in the same manner.

216. Does a British fuse behave accurately as regards the time taken for it to detonate?

There is considerable latitude allowed in the amount of delay. In fuses used in British 15" shell the specification states that a shell fired at a 6" plate at 20° to the nor' with a striking velocity of 1500 f.s. must detonated between 20 and 45 ft. From the plate.

217. Would you expect German fuses to have similar tolerance?

I think it is very probable that the tolerances would be of the same order.

218. Have you experience of actual delays of the explosion of German shell during this war?

In the action of the River Plate, 2 hits received by H.M.S. EXETER with 11" shell showed that the delay in these 2 cases was 65 and 70 ft. respectively. In neither case did the shell experience any serious obstruction.

219. At a range of 16,500 yards, an angle of descent of 20° from the horizontal and an inclination of 60° from the fore and aft line, a shell could penetrate the 7" armour belt of HOOD, penetrate the 2" slope of the armour deck and burst in the vitals of the ship. This would mean a delay in the order of 55 ft. from the ship's side. Do you think such a delay is possible or probable?

Yes, I think it quite possible and even probable if our estimate of German delays is correct.

220. A shell fired from the same gun could also pierce HOOD'S ships side under the 12" belt and burst in the vitals. This would mean a delay of about 75 ft. from the time of impact on the water and about half this distance would be through water, Do you think this delay is possible?

I cannot say definitely because we have insufficient data of a projectile's behaviour when travelling through water. It is not known to what extend water reduced the velocity but I think a length of delay of 75 ft. under these conditions is improbable.