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

- Page 89 -

SECRET

ADMIRALTY

Rex House,

REGENT STREET

S.W.1.

12^TH September, 1941

Be pleased to inform Their Lordships that in accordance with N.L.9821/41 of 31^st July we have carried out a thorough and careful enquiry into the technical aspects of the loss of H.M.S. HOOD. We have taken evidence from a total of 176 eyewitnesses to the disaster, these included 71 from H.M.S. PRINCE OF WALES, 89 from H.M.S.NORFOLK, 14 from H.M.S.SUFFOLK and 2 from H.M.S.HOOD.

An extract from the previous enquiry of a statement by Midshipman W.J. Dundas late of H.M.S.HOOD is included as he was not available to give evidence to us. Extracts from statements made by prisoners from BISMARCK are also included. N.I.D's representative informed us that further questioning of these prisoners as regards delay action of fuzes, etc., would lead to no result.

Evidence was also taken from two officers who have recently served in H.M.S. HOOD. Technical witnesses included representatives nominated by the Director of Torpedoes, Director of Naval Ordnance, Director of Torpedoes and Mining and Chief Superintendent of the Research Department.

We have been assisted by Captain J.F.B.Carslake, R.N. of Torpedoes and Mining Department and Mr. D.E.J. Offord, Chief Constructor, of the Naval Construction Department. Our report and conclusions are attached.

(signed)

L.D. Macintosh

CAPTAIN

R.D.Duke

CAPTAIN

H.T.C.Walker

REAR ADMIRAL

- Page 90 continuing to page 91 -

SECRET

NARRATIVE

(Deduced from evidence)

The action was fought between H.M.S.HOOD (Captain R. Kerr, C.B.E.,R.N.) wearing the Flag of Vice Admiral L.E. Holland, C.B., H.M.S.PRINCE OF WALES (Captain J.C.Leach, M.V.O., R.N.) and the German battleship BISMARCK in company with the German 8-inch cruiser PRINZ EUGEN. Tracings of the tracks of the British ships (inclusing H.M.S.NORFOLK (Captain A.J.L.Phillips R.N.) wearing the Flag of Rear Admiral W.F. Wake-Walker, C.B., O.B.E, and H.M.S.SUFFOLK (Captain R.M. Ellis R.N.) are attached. (Exhibits "A" and "B").
HOOD opened fire at approximately 0553 on May 24^th, her course then being 300 degrees, range about 26500 yards. BISMARCK and PRINCE OF WALES opened fire very shortly afterwards. According to the statements from survivors of BISMARCK, PRINZ EUGEN also fired at HOOD over the BISMARCK (See C.B.4051(24) OF August 1941, page 14)
At 0555 V.A.C.B.S. executed a turn together of 20 degrees to port. It is clear that HOOD's forward turrets only would bear at the beginning of the action, but there is evidence that both X and Y fired after the turn. One or more of HOOD's turrets fired just before the explosion - almost concurrently with it - and the bulk of the evidence shows that it was A and/or B.
We consider it established that the third salvo from BISMARCK hit HOOD on the boat deck with at least one shell. Other shell just short from this salvo may have hit her below the water line.
The bulk of the evidence shows that HOOD was straddled by the fifth or sixth salvo from BISMARCK, one shell of this salvo apparently hitting her on the boat deck somewhere near the mainmast, and others may have hit her below the waterline. Some witnesses stated that they saw other hits on HOOD above the water line and splashes just short from salvoes just before or after the one referred to at the beginning of this paragraph; although this evidence may not be very reliable, the possibility of further hits cannot be ruled out.
There is no very definite evidence of the fall of shot from PRINZ EUGEN, though one salvo was described as falling astern of HOOD.
Very shortly after 0555 a fire was observed somewhere on the port after end of the boat deck of HOOD. We consider it established that this fire was caused by a hit from BISMARCK's third salvo. It burned with a clear flame and appeared to spread and then die down. Just before 0600 V.A.C.B.S. hoisted a signal for a further turn of 20 degrees to port together, (the range at the time being about 16300 yards) but it was never executed as at 0600 HOOD blew up and sank in just under 3 minutes.

- Pages 92 to 108 -

Summary of findings of Second Board (Walker)

Rear-Admiral H.T.C. Walker, RN (President)
Captain H.E. Morse, DSO, RN,
Captain L.D. Mackintosh, DSC, RN.

To assist this board, as experts in explosives and construction respectively, were:

Mr. J.F.B. Carslake, RN.
Mr. D.E.J. Offord, Chief Constructor of Naval Construction Dept.

The following is the Report of the Second Board of Enquiry into the loss of HMS Hood.

Reliability and General Impression of Evidence

As might be expected in connection with such a sudden, unexpected, and stupendous happening, and the lapse of time since its occurrence, the evidence is largely confused and contradictory. It was noticeable that batches of witnesses who came from the same action stations tended to give similar evidence. This would be accounted for, not only because they would have had the same view, but because they would have talked the matter over among themselves both at the time and later. Greater weight has naturally been given to evidence of the more highly trained witnesses, but it is clear that no witness can be entirely reliable on every point. Thus Captain Leach and Lieutenant-Commander Rowell definitely testify to the appearance of the major explosion just before the mainmast; we must consider them reliable on this point and other witnesses support their evidence.

There is a distinct body of evidence, however, that places the major explosion abaft the mainmast. The conclusion that we have come to is that these phenomena we actually visible in both places almost simultaneously, and the fact that many witnesses state that the whole of the after part of the ship blew up does not conflict in any way with this conclusion. The evidence supplied by Captain Carslake as regards the noise of the explosion which sank HMS Invincible in 1916, is of interest in this connection and gives an indication of the totally different impression that a single occurrence may have on the minds of different witnesses in like circumstances.

Suffolk's Evidence

The plot shows that this ship was 28-30 miles from Hood during the action and it is obvious that little could be seen, though a mirage effect was noticeable. We consider that Commander L.E. Porter's description gives an accurate idea of the most that was visible from Suffolk. Briefly, all he saw was gun flashes from Hood and then a very thin parallel-sided pillar of orange flame which went to about 800 or 1000 feet. This was followed by a cloud of very dark smoke which developed from the bottom of the flame.

Norfolk's Evidence

The plot gives Norfolk's distance from Hood as 15 miles. A mirage effect was also noticeable from her but it is not considered likely that more than a general effect could be observed. Rear-Admiral Wake-Walker's evidence is confident and clear.

The general impression from these two ships is as follows:

A fire from the after part of the ship burnt with a clear reddish flame, and it appeared to die down and then increase. This was followed shortly by a big explosion which took the form of a high sheet of flame shaped like a fan, or inverted cone. Clouds of dark smoke surmounted the flame, and the ship disappeared. One or two witnesses, however, e/g/ Captain Phillips and Midshipmen Summers and Buckley mentioned a ball or balls of fire showing clearly in the flame of the explosion.

Two witnesses stated that they had seen (through glasses) a complete mainmast, and two others what might have been mast or derrick. Although debris could probably be seen, too much reliance cannot be placed on the evidence to its nature.

Prince of Wales' Evidence

The proximity of this ship to Hood and the fact that she was in action at the same time prevented many observers from giving a clear-cut impression of the occurrence. It is fairly certain that no one observer could record every detail of what he saw and heard.

Very careful consideration of the evidence shows that the following outstanding impressions were recorded by witnesses from this ship.

The Fire

It is clear that a fire was started on the port side of the boat deck of Hood by the third or fourth salvo from Bismarck. Opinion was divided whether it originated before or abaft the mainmast (the bias is abaft) but it evidently spread with very great rapidity and covered a considerable portion of the boat deck. This fact and the inclination of Hood from Prince of Wales would account for the difference of positions given.

The most reliable evidence shows that the colour of the fire was of a reddish or orange hue with not very much smoke - the latter being of a brownish or black colour, but colours from bright yellow to dull red and even blue were recorded.

Several witnesses who had experienced cordite fires definitely specified the fire on the boat deck as such. Lieutenant-Commander Rowell describes it as "like a petrol fire." Petty Officer Coates said he saw a roll of flame from the after screen under the boat deck which enveloped the after turrets.

The Explosion

Evidence as to the seat of the explosion is divided between before and abaft the mainmast, there being a bias towards the former. Captain Leach and Lieutenant-Commander Rowell who was the navigating officer of Prince of Wales gave the position as before the mainmast.

Some witnesses only record a flash of the explosion but others who were more likely to have a keener appreciation of rapid events sat that the flame of the explosion had definite duration. One of the most reliable witnesses, Captain Leach, was impressed by the effect which he described as like a vast blowlamp. Chief Petty Officer French said the boat deck appeared to rise in the middle before the mainmast.

As might be expected, the colour of the explosion was difficult to record, but it appears from the evidence that it was probably of a reddish or orange colour. It was accompanied by a vast amount of smoke which enveloped the ship. Lieutenant-Commander Rowell describes a dense column of white smoke which almost had the appearance of steam. Other witnesses talk of yellow, brown and white, light grey and black, and black. Sub-Lieutenant Wormersley who is a chemist in private life had the impression of "a colossal volume of brown smoke with a dull red glow all the way along the base of it." The main impression of Lieutenant Beckwith, Second Gunnery Officer of Prince of Wales, was dark thick yellow smoke which he associated with cordite, and this was confirmed by Chief Petty Officer French. Petty Officer Sweet said the stern was not obscured by smoke but was blown to pieces.

The large majority of witnesses heard no noise of the explosion. A few talk of rumbling and muffled noises, dull thud, loud thumps or a tremendous roar.

Debris from the Explosion

Very few witnesses can be very definite as to what they saw and "a large number of small pieces" describes the general impression. Several noticed one particularly large bit high in the air. Part of the mainmast or main derrick were stated to have been observed by a few witnesses and in one instance the complete mainmast was claimed. One witness is positive he saw a complete 15-inch turret with two guns and a single gun in the air and five other witnesses claim to have either seen single 15-inch guns or part of the gun-house of a turret.

Last view of Hood after the Explosion

The ship was obviously so enveloped in smoke and she disappeared so quickly that no one witness got a complete clear picture of the Hood after the explosion. Lieutenant-Commander Rowell saw her foretop falling backwards and the stern slipping forwards. He said that as Prince of Wales drew abreast of Hood, all that could be seen was what appeared to be three large sections of the hull which were unrecognisable and slipping underwater. Other witnesses were clear that the forepart of the ship was not damaged and several of them saw her forepart sticking out of the water at a very steep angle and slipping backwards under water, turning over as it did so. Lieutenant-Commander Terry said he saw her down by the stern, listing heavily to port; the after part of the ship appeared to be a mass of twisted framework. Able Seaman Paton said he saw her turn to port, roll over, and that two funnels were visible lying on the water while he also saw a jagged part of the stern. A certain amount of burning oil on the water was seen by a number of witnesses. The evidence shows that she sank in three minutes or under.

Enemy Fall of Shot

Evidence generally indicates that the first salvo from Bismarck fell ahead of Hood, and the second astern. The third fell in line and probably hit. The fourth salvo was close short and the fifth or sixth probably hit. A salvo of 8-inch, apparently HE (High Explosive), was also observed and it was thought that this was astern of Hood, but its sequence in regard to Bismarck's salvoes is not clear.

Miscellaneous

Other points brought out in evidence were that A and B turrets fired just before or simultaneously with the explosion. Some witnesses stated that X or Y also fired just before the explosion.

Two witnesses were impressed by the excessive flame that once came out of the muzzles of B guns and another reported a similar happening from X guns. No importance is attached to this.

No abnormal shock which could be attributed to the blowing up of Hood was felt by any witness who was below the waterline in Prince of Wales. But under the existing circumstances such a shock might have passed unnoticed.

HMS Hood Survivors' Evidence

Midshipman WJ Dundas was not available for interrogation, but the following is an extract from the evidence he gave before Admiral Blake's Board:

Midshipman Dundas was employed as a Midshipman of the Watch on the upper Bridge during the action. The upper bridge was closed in and had no view aft. His position was amidships at the chart table, and he saw very little.

The first salvo from Bismarck fell on the starboard bow of Hood. The second on the port bow. After the third salvo the torpedo officer, who was at the starboard after end of the bridge, reported a cordite fire on the starboard side of the boat deck.

Hood fired at least one salve after this report, and was still steaming fast. About the fourth or fifth salvo from Bismarck everyone on the bridge was thrown off their feet. Wreckage started to come down. On getting to his feet, Dundas saw a mass of brown smoke drifting to leeward, on the port side. The ship was listing heavily to port, and he scrambled uphill and started climbing through one of the windows. He saw the bows of the Hood at an angle of about 45°, with the forefoot just clear of the water, sliding backwards on an even keel.

He is quite sure that the ship received no hits forward. His recollection is that there was a complete silence everywhere after the shock, and that the ship had stopped and was heeling quickly to port. There was no blast bigger than that of the ship's own guns firing.

R.E. Tilburn, AB, impressed us as being a very intelligent man, though inexperienced, as was still obviously shaken by his ordeal. His was the only firsthand evidence of what happened on board, from an observer who could see aft. But he was lying down most of the time - on the boat deck before the port UP mounting - so his view was restricted.

He stated Hood was hit near the port midship UP mounting and that a fierce fire resulted. This fire did not seem to spread, but he thought Ready Use ammunition was affected as he heard noises like "explosions of a big Chinese cracker." He thought it was too far forward for a petrol fire; his evidence as regards the petrol stowage was, however, rather shaky.

He stated that the 4-inch ammunition hatch on the boat deck (port side) with which he was familiar was definitely closed during the action.

As regards the explosion, he states that tremendous vibration resulted from another hit; he did not see much, but "a lot of grey smoke." There was a noise as if the guns had fired, then silence. One flash of flame came between the control tower and B turret above the forecastle deck just as he was going into the water. A lot of debris and bodies fell over the decks, but apart from the fact that some of the bodies were those of officers, he could identify nothing.

Other Points of Interest

(1) He states A and B turrets only fired - we cannot consider his evidence conclusive.
(2) He testified to the extreme rapidity with which the ship sank.
(3) He says that when in the water he saw long steel tubes - approximately 15 feet long and 1 foot in diameter - sealed at both ends, floating in the water. We consider that they may have been crushing tubes from the bulges - this would confirm the magnitude of the damage and might be an indication that the ship broke her back.

A.E. Briggs, Ordinary Signalman, was another quite intelligent witness, though being on the compass platform he could not see much. But he was in a position to overhear the talk of some officers.

Important points are:

(a) The Senior Gunnery Officer said: "She has been hit on the boat deck and there is a fire in the ready Use lockers."
(b) The Vice-Admiral said: "Leave it till the ammunition is gone."
(c) Immediately after the explosion the Officer of the Watch stated the "compass had gone". This would be the gyro-repeater on the compass platform.
(d) Briggs stated that there was not a terrific explosion at all regards noise. He saw no debris coming down.
(e) He testified to the great rapidity of Hood sinking.

Some Outstanding Points in the evidence given by Technical Witnesses:

(1) A warhead would not be detonated by a shell unless it burst inside the mantlet.
(2) One warhead detonating in Hood would detonate the next one in the horizontal plane. Warheads on one side of the ship would not detonate warheads on the other side. To sum up, one shell would not cause more than two warheads to detonate.
(3) If the warheads detonated, they would not detonate the 4-inch or 15-inch magazines.
(4) The effect of fire round a warhead would possibly lead to an explosion but it would have to be a fire of fierceness and duration and the result would probably be comparatively mild.
(5) That if any of the after 4-inch magazines, except the forward upper one, exploded it would explode the after 15-inch magazines.
(6) The aural and visual effects of warheads going off would be a noise of a sharp loud crack and a bright flash, which would be instantaneous, and which the experts variously described as likely to be dull red, dark red, reddy brown or bright yellow (lighter than cordite). Smoke would be black, light brown and grey, and possibly white.
(7) There was not unanimity of opinion about the effect on the ship if two warheads detonated. DTM (Director of Torpedoes and Mining), DNO and CSRD's (Chief Scientist, research department) representatives considered that although the structure in the immediate vicinity would be shattered and some of the 5-inch and 7-inch belt would be blown away, it would not cause a serious rent in the ship's side below the waterline, and they were convinced that the effect would not be disastrous. DNC's representative on the other hand considered that the strength deck would be destroyed for a considerable width, and the main deck ruptured. There would be a sufficient rupture below the waterline to cause the water to be scooped in and break down the after bulkheads as far as 259 and possibly 280 which would cause the ship to sink very rapidly.
(8) The aural and visual effects of a 15-inch magazine blowing up would be a rumbling noise (unless it detonated I which case it would be a sharp explosion) accompanied by a spurt of bright yellow flame of some duration ( as opposed to a flash) and smoke. The smoke was described by the experts as:

(a) dark and some white like steam
(b) dense and dirty
(c) black, perhaps grey and
(d) reddish

The first kick of the explosion would take the easiest path but there might be other effects in other places.
(9) The "balls of fire" seen in the explosion could not be explained except that they might have been partly ignited cordite charges taking fire in the air; or ignition of projected oil fuel.
(10) There was general agreement that

(a) The description of the explosion given by Admiral Wake-Walker, Captain Leach and Dub-Lieutenant Womersley is as caused by a large cordite explosion. Cordite on the upper deck would not cause the main effect seen.
(b) That the fire on the boat deck had nothing to do with the explosion. It was probably caused by 4-inch ready Use or UP ammunition. A fire of either of these would not produce disastrous effects.
(c) It would be impossible for an untrained witness to differentiate between a 4-inch and UP ammunition fire.

(11) Bismarck's shells probably had a muzzle velocity between 2721 and 3150 feet per second.
(12) If the muzzle velocity was more than about 3050 fps a shell could have penetrated Hood's 12-inch belt and have got at a vital area (i.e. in or near a magazine).
(13) If it was as low as 2721, although it could not penetrate the 12-inch belt, there is a strip on the ship's side about 18 inches deep and 42 feet long where the shell could enter and pass over the top of the 12-inch belt and yet get under the flat portion of the protective main deck. With a fuse delay of about 55 feet it could explode in a vital part.
(14) There is a zone a few feet wide the length of the magazine group where a shell could fall short of the ship and enter the ship below the armoured belt. Assuming a fuse delay of about 75 feet this shell could get to a 15-inch magazine and with a delay of 55 feet get to a 4-inch magazine. About half the travel would be underwater.
(15) German shells probably have longer fuse delays than ours and experience shows that their fuses are fairly erratic. In the action off the River Plate, two German shells burst 65 and 70 feet respectively.
(16) Little is known of underwater trajectory but the general opinion was that if a shell hit below the waterline it would be slowed up so much that a fuse delay of 75 feet under these circumstances would be unlikely.

Cause of the Ship's Destruction

The very sudden and total disappearance of the ship clearly shows that the explosion which sank her was of great magnitude. As noted before, much of the evidence is contradictory and inconclusive, and we realise that many points in connection with the loss of Hood can never be proved definitely.

1. Visible evidence
The first visible evidence of damage which might possibly have led to the destruction of the ship was a fire on the boat deck. It has been established that this followed immediately on a hit on the boat deck, probably from Bismarck's third salvo.

2. Position and Extent
The exact position of the hit and/or the start of the fire is in doubt, but the bulk of the evidence shows that the fire first appeared on the port side and abaft the mainmast. It is certain that it spread very rapidly until it covered a large part of the port side of the boat deck, but there is very little evidence that it spread below. There was no sign of Hood's speed decreasing before the explosion and it might be inferred that the fire had not, therefore, affected the engine rooms.

3. Appearance
Evidence as to the colour of flames, smoke and other phenomena observed in this fire differs very considerably, but analysis of the most reliable evidence indicates that it burned with a reddish/orange flame and comparatively little smoke. Distant observers emphasise the red.

4. Cause
(1) There are three possible causes of such an immediate and rapidly spreading fire
      (a) Petrol
      (b) 4-inch ready Use ammunition
      (c) UP ammunition
(2) The exact amount of petrol which was on board at the time cannot be definitely stated, but if the order known to be in force in Hood a short time previously were carried out - and there is no reason to suppose otherwise - there is no reason to suppose that there was more than two gallons. This would have been on the boat deck abreast the mainmast. There is reason to believe that the petrol stowage in Hood was carefully supervised and not withstanding the opinion of Bismarck's officers which was based on a false assumption, the Board consider it unlikely that petrol was the cause or at any rate the sole cause of this fire.
(3) Eighty rounds of 4-inch ready Use ammunition were stowed in light type lockers on the boat deck and on the foc's'le deck. It is quite possible that either 4-inch or UP or both could be ignited as the result of a shell bursting in their vicinity and there is definite evidence from the survivors that ammunition was in fact exploding in the fire. One survivor (Briggs) gave evidence that the Senior Gunnery Officer reported a fire in the ready Use lockers and Midshipman Dundas is stated to have informed the previous Board that the Torpedo Officer had reported a cordite fire on the starboard side of the boat deck. The noises like big Chinese crackers heard by A.B. Tilburn may have been UP ammunition exploding.

Evidence as to orders which were known to be in force in Hood a short time previous to the date in question regarding the supply of 4-inch ammunition, makes it practically certain that all the hatches in the train of supply would definitely be closed. The evidence of the expert witnesses also shows that the results of a fire amongst the 4-inch ready Use ammunition and UP ammunition should not be fatal to the ship.

5. Conclusion
We have made a careful study of the plans showing stowage of 4-inch and RU ammunition; the evidence clearly shows that some of this caught fire. After consideration of all the evidence and bearing in mind that Hood was definitely hit again after the fire had started, and almost immediately before the explosion, we have come to the conclusion that the fire was not in itself the cause of, and was distinct from the explosion that destroyed the ship.

6. Some cause other than the fire must therefore be sought for the explosions, and the three potential dangers are obviously as follows:
(1) Torpedo warheads,
(2) 4-inch magazines,
(3) 15-inch magazines

7. As regards the torpedo warheads, we put ourselves the following questions:
(a) Could one or more have been caused to explode during the action?
(b) Does the evidence of eyewitnesses correspond to what one might expect to see or hear if one or more warheads detonated or exploded?
(c) Would the explosion or detonation of one or more warheads have caused the ship to sink so rapidly?

8. With reference to (a). Evidence of eyewitnesses, Repulse and an Officer who had recently served on Hood leaves little room for doubt that the mantlet doors were closed. A warhead could still, however, have been detonated or exploded by a direct hit from Bismarck's shell. There is no direct evidence that such a hit occurred, but it may have done so on either side of the ship. If a single warhead had gone off, one other, but probably not more than one, would also have gone off.

With reference to (b). Expert opinion suggested that the explosion of two warheads would produce an all round, almost instantaneous flash. It would not have produced the very high columns of flame of appreciable duration which was seen by so many witnesses. Nor was the noise, reported as being heard, compatible with that of a TNT detonation or explosion. The consensus of expert opinion was definitely against, the characteristics of the explosion as given in evidence by eyewitnesses being that of TNT.

With reference to (c). Mr. Offord, our advisor in construction, was of the opinion that this could be the case. Other witnesses, experts in explosives but not in construction, were of the opposite view, and the Board are not convinced that such a very rapid sinking would follow from the damage which Mr. Offord considered would result from the explosion of two warheads. Further, there is strong evidence that the widespread and immediate damage actually caused to the after part of the ship was considerably greater than that which Mr. Offord considered would result from two warheads exploding.

We have therefore come to the conclusion that, although the explosion or detonation of two warheads cannot be entirely excluded that this was not the direct cause of the sinking of the ship. As regards the 4-inch and 15-inch magazines the following questions arise:

(1) Is it likely that enemy gunfire during this action would "blow up" any or all of the magazines?
(2) Would the blowing up of magazines produce the effects seen and heard by witnesses?
(3) Would the blowing up of any or all of the magazines cause the rapid destruction of the ship?

Here again, expert advisers were consulted, and lead us to the following conclusions:

As regards (1). Expert evidence shows that this is quite possible if the muzzle velocity of Bismarck's shell was between 2721 and 3050 fps. If the muzzle velocity was over 3050 fps, the probability, bearing in mind the evidence as to the fall of shot, is considerable.
As regards (2). We consider that what was seen and heard was in accordance with what might be expected if the after group of 4-inch and/or 15-inch magazines of Hood had blown up. There is one important point which needed careful consideration and which was remarked on by DNC in his minute NL 9821/41 (Report of previous Board of Enquiry) and by C in C Home Fleet, on NL 11131/41; namely that the position of the explosion as observed by some competent witnesses was much further forward than would, at first sight, have been expected had the 4-inch or 15-inch magazines blown up. This is partially explained on page 3 where we reached the conclusion that not only was a tremendous pillar of flame observed just before the mainmast, but that, in addition, a very heavy explosion was seen practically simultaneously further aft.
Commander Maton and Commander Knight agreed that if the 4-inch magazines went off first, followed instantaneously by the 15-inch, the first visible sign might well be a large sheet of flame directly above or just before the 4-inch magazines. Finally, it must be remembered that our peace time knowledge and practical experience of the results of cordite explosion has been based on experiments with a maximum of about half a ton of cordite. Hood's after magazine contained about 112 tons, over two hundred times as much. The course of the explosion following on the terrific pressures likely to be produced in this case must be difficult to predict. From the last was there are three examples of the effects on battle cruisers of cordite explosions - explosions which both in appearance and effect gave very similar results to those experienced in the loss of Hood. As regards (3), there is little room for doubt that the immediate destruction of the after end of the ship followed by the rapid sinking of the remainder would result from the blowing up of the 4-inch or 15-inch magazines - in the case of the former because their explosion would cause the 15-inch also to blow up.

Conclusions

We conclude

(1) That the sinking of Hood was due to a hit from Bismarck's 15-inch shell in or adjacent to Hood's 4-inch or 15-inch magazines, causing them all to explode and wreck the after part of the ship. The probability is that the 4-inch magazines exploded first.
(2) There is no conclusive evidence that one or two torpedo warheads detonated or exploded simultaneously with the magazines, or at any other time, but the possibility cannot be entirely excluded. We consider that if they had done so their effect would not have been so disastrous as to cause the immediate destruction of the ship, and on the whole, we are of the opinion that they did not.
(3) That the fire that was seen on Hood's Boat Deck, and in which UP and/or 4-inch ammunition was certainly involved, was not the cause of her loss.

- Page 109 -

Enclosure 2.

Minutes of A.C.N.S. (W), V.C.N.S., Controller,
First Sea Lord and First Lord

The conclusion of the Board of Enquiry is that the after 4" magazine probably exploded first, followed by the after 15" magazine, which is only natural as it was so near. As the charges in the 4-unch magazine were QF charges in brass cases it seems probable that the explosion was due to a direct hit in the magazine and not to a "flash" and so the only question at issue from this case to prevent a repetition is hot to protect the magazine from a direct hit.

2. From D.N.C's remarks on BISMARCK in other papers it seems that the magazines of modern German ships are no more better protected, and possibly not as well protected as the magazines of our newer ships. Our Capital ships suffer however from the serious effect of the vulnerability to "flash" of the ingitered B.L. cartridges. This has been overcome in 8" charges and smaller by doing away with the powder igniter and using a 1-inch tube for firing. This solution has not as yet proved practicable for charges of heavier guns, but is being discussed on other papers.

3. The German solution is a brass case.

4. I will defer further remarks until consideration of "X" above is complete.

(Note: Final two sentences above have been marked "X" in the margin)

(Signed)

R. McG

ACNS (W)

Both Boards of Enquiry consider that the HOOD was lost due to a magazine explosion.

We cannot get away from the fact, therefore, that the magazines in our ships have blown up on several occasions in this war and in the last, whereas, as far as I know, there have been no cases of German ships blowing up although the BISMARCK and the LUTZOW (in 1916) were given a tremendous hammering by gunfire before the former had to be torpedoed by us and the LUTZOW by the Germans before they could be sunk.

If these reports by the two Boards of Enquiry are accepted, as I think they should be, then we want

To provide such protection to the magazines of our ships as will prevent enemy shells from penetrating them.
To provide ammunition that is not likely to be detonated.

We do not know for certain whether the primary cause of our losses has been due to lack of protection in the magazines or a weakness in our ammunition. I think, therefore, that we should take active steps as regards both (a) and (b) but if we could achieve (a) fully this would provide security even if our ammunition remains suspect.

I do not think we should allow D.N.C's remarks on other papers, that the magazines of German ships are no better protected than our newer ships, to deflect us from making our magazines safe from penetration if this is practicable.

(Manuscript addition)

What evidence have we as regards the comparative destructive powers of our shells and German shells.

(Signed)

HRM

- Page 110 -

Noted

2. Magazine is good in our new ships, poor in older ships.

3. We have put in some additional armour in R class but it is not very satisfactory.

BAF

6/12/41

I do not think that there is much doubt that the HOOD was lost as the result of the explosion of the after magazines and that no blame attaches to the Vice-Admiral Commanding the Squadron, the Captain or anyone else.

2. The two main points which have been brought out in these minutes concern magazine protection and detonation of ammunition.

3. It was known that HOOD's protection was poor by modern standards and had it not been for the war she would by now have been undergoing complete reconstruction.

4. This docket has been held up during my absence in Washington but, in the meantime, A.C.N.S.(W) has been going into the matter. I enclose a further minute from him, dated 22^nd January, describing the present situation.

5. The protection of magazines against direct hits has been investigated recently by D.N.C. in comparison between the BISMARCK and the K.G.V. and the result of his investigations is attached.

6. With regards to protection from flash, it is obvious that we cannot alter existing ships to brass obduration and it is, therefore, necessary to do all we can to make our ships as little liable as possible to blowing up of magazines.

7. The Secretary suggests that the report of the Board of Enquiry be brought before the Board and, if First Lord approves, I consider that at the same time the Board should have before them, and at an early date:

a report showing exactly what lessons were learnt from the destruction of HOOD;
what action has been taken on these lessons;
a report showing:
why presnet igniterless charges cannot be used in guns above 8";
in what manner the tinfoil covered igniters are likely to prevent a magazine going up;
what action is being taken to get an igniterless charge in guns above 8" and whether this matter is being treated as of transcending urgency.

8. In notice that D.N.C. in remarking on damage to BISMARCK is not surprised that she stood up to 5 torpedoes. This makes it all the more necessary to determine why PRINCE OF WALES suffered so severely from at most 2 torpedoes.

(Signed)

1^st February 1942

(Manuscript note below)

Concur with First Sea Lord's paras 7 and 8. Action accordingly.

AVA

4/2

- Page 111 -

SECRET

First Sea Lord

(Through Controller)

(Initialled - BAF 24/2/42)

With reference to the First Sea Lord's minute of 1^st February, 1942 on N.L.16248/41, paragraph 7, the remarks from the Constructional and Ordnance aspects respectively are attached as Enclosures I and II.

2. It is desirable to draw the attention of the Board to the following additional points:

RODNEY, all QUEEN ELIZABETH Class, REVENGE, RAMILLIES and EREBUS have not yet got cartridges with concentrated igniters with non-removable igniter covers, and more than half of our 16" and 15" reserves of cartridges are also of the old type with spread igniters. RODNEY should receive the new type of cartridge during her present refit.
6 of our 8-inch cruisers still have cartridges with igniters and part of 8-inch reserves of cartridges are of the old type.
All new filling of 15" cartridges is to concentrated igniter design and 8" cartridges to igniterless design. Opportunities are being taken as latest type cartridges become available.
It will be noted that no solution has yet been found to the problem of providing igniterless charges for guns above 8-inch.

(Signed)

R. McG

24^th February, 1942

- Page 112 -

APPENDIX TO ENCLOSURE III.

CONSTRUCTIONAL.

The principal lesson of the loss of H.M.S. "HOOD" is that the magazines of a warship should be so situated and protected that, so far as can be foreseen, it is impossible for a shell or splinters of a shell to penetrate such a vital compartment. This is not a new lesson. It was learned during the last war and applied to the two capital ships designed after that war, the magazines being placed below the shell room and below very heavy deck armour of a new type developed for the purpose.

2. Since that date the necessity for such a change in design has been emphasised by the results of a long service of magazine trials and the development of aircraft carrying heavy bombs.

3. This lesson was applied as far as practicable when the older capital ships were reconstructed. It was intended to reconstruct "HOOD" in this way after "QUEEN ELIZABETH" was completed, but the outbreak of war prevented this. Except for "ROYAL OAK", nothing was done to the "ROYAL SOVEREIGN" class, as these ships were to be scrapped when the ships of the "KING GEORGE V" Class were completed. It was not possible in these old ships to place the magazine below the shell room.

4. The present situation in regard to the capacity of existing capital ships to withstand German 15" shell reaching the magazines is as follows:-

(a) Side Protection: Main Belt

At 90° Inclination	"KING GEORGE V" Class	Immune outside about 15,000 yards.
	"NELSON" and "RODNEY"

	"QUEEN ELIZABETH" Class	Immune outside about 18,000 yards.
	"ROYAL SOVEREIGN" Class

	"RENOWN"	Can be defeated at all ranges up to 28,000 yards

(b) Deck Protection

KING GEORGE V" Class	Immune inside about 34,000 yards
"NELSON" and "RODNEY"	Immune inside about 35,000 yards
"QUEEN ELIZABETH" Class	Immune inside about 27,000 yards

"ROYAL SOVEREIGN" Class	Vulnerable - see Para 5.
"RENOWN"	Immune inside about 24,000 yards

5. With reagrd to the "ROYAL SOVEREIGN" Class, it has been approved since the loss of "HOOD" to add 2" N.C. armour over the magazines as opportunity offers, this is the most that can be fitted without extensive reconstruction involving re-bulging. This addition only provides protection against 15" German shell inside 20,500 yards.

6. It appears likely that the German shell which caused the destruction of "HOOD" entered the ship at fine inclination and penetrated the protective deck forward of the area where deck protection had been added over the magazines during construction, it then travelled a considerable distance.

- Page 113 -

before bursting. The protection of all our capital ships has been carefully reviewed to ascertain if at fine inclination it would be possible for a shell with a long delay to dodge the main protection and burst near a magazine. As a result of this examination the following action has been approved:-

"NELSON"

Fit an armoured bulkhead forward from hold to platform deck. This will be completed during the present refit.

"RODNEY"

As "NELSON". Also fit as early as practicable the additional lower deck armour approved before the war and already fitted in "NELSON".

"QUEEN ELIZABETH" Class.

Fit an armoured bulkhead forward and increase the area of the umbrella over the magazines. This has been done in "WARSPITE", armour has been ordered for the remaining ships.

The above is shown on the enclosed drawing, D.N.C. 2/A.595.

7. Although not a lesson of the loss of "HOOD", it was a less on the same action that a German 15" diving shell might enter a ship below the armour belt and burst near the magazine. Although a German shell did enter "PRINCE OF WALES" in this manner, it was not in a condition to burst, and it is thought that if it had been in such a condition, the burst would have occurred before it reached the ship. Nevertheless, additional splinter protection to guard against such a possibility has been fitted in "DUKE OF YORK", "ANSON", and "HOWE", and is an approved A & A for "KING GEORGE V". Owing to the work and time involved, nothing can be done in this respect to the older capital ships unless they were taken in hand for expensive repairs - say requiring 12 months.

8. Action has been taken (a) to land U.P. mountings and ammunition, (b) to call to the attention of all ships to the need and to the desirability to guard against the dangers arising from ready-use ammunition in the upper works. But with the great increase in close range A.A. armament, the risk in the latter respect must be taken. In particular the very large increase in the close-range A.A. armament of "VANGUARD" necessitated fitting as a pom-pom a compartment just below the W.L. thought below the 6" armoured deck.

9. Since the A.W. torpedo-tubes of "HOOD" were suspected as contributing to the loss, it was proposed to remove these tubes from "RENOWN". Action has been taken to remove the forward tubes, but the after tubes are still on board.

Page 114

APPENDIX TO ENCLOSURE III.

ORDNANCE.

What lessons were learnt from the destruction of HOOD.

D.N.O. concurs with D.N.C. and so far as the principal lesson is concerned has nothing to add to his remarks in paragraph 1 of his minute of 13.2.42. It is well known that if a ship is hit in the magazine and the shell explodes the magazine will blow up whether the charge is ignitered of not, or whether it is carried in a silk bag or brass case. Examples in Foreign Navies are the French Battleship BRETAGNE at Oran, the Italian Destroyer ARTIGLIERE, the American Battleship ARIZONA and Destroyer SHAW (photograph attached), also the German raider sunk by H.M.S.CORNWALL.

D.N.O's remarks are therefore confined to the other lessons leant and which have been examined under the following heads:-

Entry of flash into the magazine from a source outside the magazine.
Vulnerability of B.L. Charges during their passage from the magazine to the gun.

In general the penetration of the magazine by flash of shell or bomb explosion from a source outside the magazine, or of cordite fires being propagated from the gunhouse via the chain of cordite charges down through the turret to the magazines, is prevented by an elaborate system of flashtight arrangements.

HOOD provides no data about the efficiency of the flashtight arrangements fitted in that ship, as the short time which elapsed between the observation of the hit and the explosion occurring, indicates that the magazine was penetrated as a direct, and not indirect, effect of the shell burst.

In other ships, notably the SUFFOLK, our flashtight arrangements have proved successful. It must be emphasised however, that the efficiency of the flashtight arrangements in the turret is dependent on the structure itself not being wrecked or distorted by bomb blast. This point was well brought out in the case of the bomb damage to SUFFOLK already referred to. This leads to consideration under head (ii) - The vulnerability of B.L. Charges.

Unless a charge is contained in a covering which is flashtight and yet which is consumed in the gun, a charge must be exposed bare at some time in its passage from the magazines to the gun.

As the result of the lessons learnt at Jutland, it has been our practice up to the present to protect our heavy gun B.L. charges by passing them from one flashtight compartment to another. This system has proved successful provided the flashtight compartment is not distorted by blast.

A further point, although not directly a lesson learnt from the HOOD, was the possible source of danger in that by incorrect drill, and in contravention of the magazine regulations, too much cordite is being exposed in the magazines at one time. The attention of the Commanders-in-Chief was called to the necessity for particular care in this direction by Admiralty General Message.

- Page 115 -

What action has been taken on these lessons.

This is summarised as follows:-

Development of protective coverings for 15" charges for VANGUARD (Note:- In this ship the handling room is above the magazine.) Subject to satisfactory trial it is hoped to be able to apply this form of protection in all 15" ships.
Attention of Commanders-in-Chief drawn to the necessity for particular care in the strict compliance of magazine regulations as to the number of charges to be exposed out of their magazine cases at any one time.
The Ordnance Board have been asked to investigate the relative liability of the following types of propellant to accidental ignition by Flash:-
Cordite S.C.
Flashless
Nitro-cellulose.

(Note:- It is of interest that a sample of cordite ex GRAF SPEE was identified as being of the Nitro-glycerine type similar to our S.C Cordite.)

(1) Why present igniterless charges cannot be used in guns above 8 inch.

The use of powder igniters in 8 inch and 6 inch Mark XXIII guns has been superseded by igniterless charges with one inch tubes. In order to obtain satisfactory ignition with one inch tubes, a vent channel of diameter 0.4 inches is required.

When considering igniterless charges for guns above 8 inch it was established by trial that a one inch tube was inadequate to give sufficient ignition.

Trials using a one and a quarter inch tube and a 0.4 inch vent channel were carried out in an experimental 12 inch gun. It was found that under these conditions severe erosion of the vent channel took place, resulting in rapid increase of the diameter of the vent channel to 0.5 inch. Previous trials had established the fact that if a gun with a vent channel of 0.5 inch diameter is fired with the vent unmasked, the resulting back flash is such as to cause material damage and to endanger the whole of the gun house crew. This therefore ruled out ingiterless charges with one inch tubes for guns above 8 inch calibre.

(2) In what manner the tinfoil covered igniters are likely to prevent a magazine going up.

The effect of the 3-ply non removable igniter cover (viz. Viz 2 layers of cashmere with a layer of tinfoil 0..1" in between) is to make the igniter no more susceptible to flash than the silk cloth covering the rest of the charge.

The Mark I Cartridge has a plate igniter with a tear off disc (or removable igniter cover).

The weakness of this lies in the fact that the tear off disc has to be removed in the handling room and the charge with exposed igniter is bare throughout its passage from the handling room to the gun.

As the result of trials carried out by EXCELLENT in 1933 it was established that a powder igniter covered by a tear off disc or a 3-ply non removable igniter cover was no more susceptible to flash than the body of the charge itself. These trials also showed that there was nothing to choose between the two types of cover in this respect.

The chief merit of the non removable igniter cover is that the powder igniter is never exposed. Moreover, the 15" Mark II Cartridge with the non removable igniter cover is fitted with a concentrated igniter, the surface area of which forms only 1/27 th of the surface are of the whole cartridge.

What action is being taken to get an igniterless charge in guns above 8" and whether this matter is being treated as of transcending urgency.

It has not been found possible to adopt igniterless charges for guns above 8 inch for the reasons given in detail under head (c) (1) above.

- Page 116 -

Enclosure 4

An extract from D.N.C's dealing specifically with para. 8 of First Sea Lord's minute of 1^st February (Enclosure 2.)

10. Para 8 of the 1^st Sea Lord's minute of 1/2/42 is not understood. The derailed report M.0251/42, which contains the survivors' narratives, shows that in the first attack the ship was hit certainly by 3 and possibly by 4 torpedoes, and in the second attack, forty minutes later, by 4 torpedoes. British aircraft torpedoes that struck "BISMARCK" contained an explosive charge of 440lbs., whilse those fired by Destroyers contained an explosive charge of 750lbs. D.N.I. has stated on N.I.D. 04842/41 that Japanese aircraft torpedoes may contain an explosive charge as heavy as 867lbs., and it would appear, from a comparison of the damage caused by Japanese torpedoes to "PRINCE OF WALES" with other torpedo damage caused by German torpedoes and British charges used for experiments, that charges as large as 867lbs. Were used against "PRINCE OF WALES". Furthermore, "BISMARCK'S" standard displacement was at the very least 41,150 tons, compared with 37,500 tons of "PRINCE OF WALES", and ceteris paribus the larger the ship the better she can withstand underwater attack.

(Signed)

SV Goodall

13/2/42

- Page 117 -

Enclosure 5.

Extract from a minute by Deputy Controller dated 18.2.42

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

It is noted that at X of his minute V.C.N.S. remarks that:-

"the magazines in our ships have blown up on several occasions in this war and the last."

The attached statement '"' shows for this war the cases:-

Where magazines are known to have blown up.
Where magazines are suspected to have blown up.
Where they have not blown up in spite of severe damage.

In the first case there is only HOOD. In the second the evidence to support the view is in most cases scanty.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

(Sgd.) C.E.B.SIMEON

Deputy Controller

18.2.42

- Page 118 -

Appendix to Enclosure 5

War Experience re Safety of Magazines.

Magazines known to have blown up
The only reported case where it is definitely known that a magazine of a British ship has blown up is H.M.S.HOOD as a result of her action with BISMARCK.
Magazines suspected to have blown up.

The following ships have reported magazine explosions:-

EXPRESS when struck by a contact mine. The forward end of the ship disappeared; the after end was brought back to harbour. Although C.O's report states that forward magazines exploded , he gives no evidence in support.
WHIRLWIND. Torpedoed and sunk. Ship's report states magazine exploded but gives no evidence in support.
JAVELIN. Hit by two torpedoes and both the forward and after ends blown off. C.O. reported after magazines exploded. A detailed investigation by representatives of D.N.C. and D.N.O. found no justification for this statement and they formed the opinion that magazine did not explode.
GRAFTON. Torpedoed and subsequent heavy explosion forward. This may have been a second torpedo or a magazine explosion.
KHARTOUM. Heavily on fire as a result of accident. C.O. that after magazine and warhead room exploded.
DELIGHT. Bombed forward - fire started. Three hours later explosion forward; may have been magazine. Ship sank.

Magazines which did not blow up under severe conditions.
BARHAM. Torpedoed abreast "A" and "B" magazines. Cordite stowage badly damaged. No fire or explosion.
EXETER. 11" hit on front of "B" turret. No cordite fire or explosion.

VALENTINE. Bombed off the Dutch Coast and abandoned. Reported a cordite fore started in the magazine but the magazine did not explode.
NORFOLK. Bombed burst just abaft "Y" magazine and disrupted the magazine boundaries. Splinters and blast perforated fixed and revolving structure. No cordite fire or explosion.
SUFFOLK. Bomb burst just before "X" magazine. Magazine bulkhead damaged. Charges ignited in the handling room, but there was no magazine explosion.
BITTERN. Bombed and sire started in small arms magazine. Some ammunition exploded but there was no complete magazine explosion.
BARHAM. Bomb perforated roof of "Y" turret. Cordite fires started in gun house, but quickly under control. No magazine or handling room explosion.
LIVERPOOL. Torpedoed and subsequently there was a heavy petrol explosion. This blew the roof off "A" turret but there is no evidence of cordite fire or explosion.
BERWICK. 8" shell passed through "Y" ammunition lobby and exploded 4' away, started fire in "y" ammunition lobby. No cordite fire or explosion.
SUSSEX. Very heavy fires as a result of bombing, but there was no magazine explosion. Magazine was flooded but only after a considereable time.
SOUTHAMPTON. Very heavily on fire, but no evidence of a amagazine explosion although one was feared.
ORION. Bomb perforated the roof of "A" turret and exploded on the after side of the roller path. Cordite fire started in "A" turret and lobby. There was no magazine explosion.
A second hit burst just over the crown of the 4" H.A. magazine and blew the armoured roof down a distance of 6'. There was no magazine explosion.
DIDO. A bomb hit "B" turret. The four top cordite charges on the port side and the five top charges on the starboard side were ignited. Remaining charges on the hoist were undamaged. Flash did not travel down to the magazine.
GARTH. Small shell burst or splinters in magazine. Cordite fire started. Quickly under control. Magazine did not explode.

- Page 119A -

Extract from
BOARD MINUTES
Friday, 13^th March, 1942;

Loss of H.M.S. "Hood"

3792. The Board considered a Memorandum on the loss of H.M.S. "Hood" which comprised the following:-

The report of the second Board of Enquiry into the loss of the "Hood."
Minutes of A.C.N.S.(W), V.C.N.S., Controller, First Sea Lord and First Lord thereon.
The note by A.C.N.S.(W) already referred to with enclosures based on reports by D.N.C. and D.N.O.
An extract from D.N.C.'s report dealing specifically with para. 8 of First Sea Lord's minute of 1^st February.
An extract from a minute by Deputy Controller;

Together with a supplementary minute by A.C.N.S.(W).

The Board took note of this Memorandum.

- Page 144 -

SECRET

APPENDIX II

EXTRACTS FROM C.B.4051(24) - GERMAN BATTLESHIP
"BISMARCK"
INTERROGATION OF SURVIVORS.

Kapitanleutenant von Mullenheim-Rechberg stated, when interrogated aboard H.M.S. "DORSETSHIRE", that "HOOD" closed the range rapidly, made smoke, and was hit as she turned to port, the smoke possibly assisting ranging. The added then that "HOOD" blew up on "BISMARCK'S" fifth salvo and cost Germany forty shells in all. During subsequent interrogation this officer stated that "BISMARCK" hit with her second salvo and again with her third, whereupon a sheet of very vivid bright, white flame was seen on "HOOD," there being no smoke at all. The absence of smoke and the nature of the flame decided "BISMARCK'S" officers that petrol storage tanks fitted for "HOOD'S" aircraft had been hit. A fourth salvo from "BISMARCK" also hit and there was an immense explosion in "HOOD." This prisoner stated that he could not say whether the explosion was caused by the development of the fire from the third salvo or by the direct hits of the fourth. He was, however, now watching closely. "HOOD" had broken her back and the forward half stood out quite clearly, being free from the dense clouds of smoke completely enveloping the after half. He stated emphatically that a further salvo was fired from "HOOD'S" forward turrets AFTER she had broken her back. It was presumed that the guns were already tilted at such an angle that the shots went hopelessly wide, for no shells were observed to fall. "HOOD'S" forward half sunk centre down, bow up. The after half was completely hidden by smoke and was not observed to sink by this prisoner.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Kapitanleutenant von Mullenheim-Rechberg also stated that "BISMARCK'S" shells all struck "HOOD" amidships. Another prisoner stated that "HOOD" was first hit by shells from Turret "A", the remaining guns then taking their ranges from this turret. This prisoner added that the shells from the secondary armamant fell short. The explosion in "HOOD" has also been described by another prisoner, who says he saw a vast flash of red flame rise many hundreds of feet into the air. He saw the ship break her back and the forward portion sink bow up centre down, followed by the after portion, stern up and centre down.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

The gunnery of "HOOD" has been described by Kapitanleutenant von Mullenheim-Rechberg as exceptionally good. The opinion of other prisoners is that "HOOD" having got "BISMARCK'S" range, would have created heavy damage, with her next salvo had it been fired. They considered that they had a very lucky escape.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX