2,000 tons of seawater in Bismarck's forecastle!

[Herr Nilsson]

Kennedy, in his book Pursuit wrote: "The third and most serious hit had...penetrated two oil tanks, come out the starboard side without exploding. This hit not only let sea-water into the oil tanks and quantities of oil into the sea, but knocked out the suction valves, cut off from the engines a further thousand tons of oil." [Viking Press, 1974, p.98].

I always wondered how this could work. There are no oil tanks above waterline.

[marcelo_malara]

I don´t agree with that Robert: shells use to fail to explode, but I think it is a rare ocurrence (if it ever happened) for them to explode when they are not intended to. For example I know many cases of unexploded aircraft bombs, but none that exploded during the freefall.

[Bgile]

I don´t agree with that Robert: shells use to fail to explode, but I think it is a rare ocurrence (if it ever happened) for them to explode when they are not intended to. For example I know many cases of unexploded aircraft bombs, but none that exploded during the freefall.

I think it does happen sometimes, but it is usually right after it arms itself, not at some later time after it hits something. Torpedo fuses will sometimes activate when the come in contact with wake turbulence.

Obviously if the shell which hit Bismarck's bow had exploded inside the bow, that would have been more serious. The same is true of the swordfish torpedo which hit Bismarck's armor belt. If it had performed properly it would have hit below the belt (or perhaps Bismarck was in a turn and the belt was lower) and caused more serious damage. Come to think of it, if the same torpedo had hit Bismarck's bow, that would have been very serious.

[Tiornu]

Premature explosions are not that rare, but they require a heavy impact. Most of the navies before WWI used bursters that were sensitive to impact and could explode spontaneously regardless of fuze action. Around 1910, several navies switched to more reliable TNT, and the US was using Explosive D. By the time of WWI, only the Japanese were still using a sensitive burster, TNA. Bismarck's forward splinter belt was probably not thick enough to induce a premature burst from a large shell.

[paul mercer]

IF the shell had exploded, would it have set off another explosion in the fuel tank? Even if it did not, what other damage would it have caused to the bow and would it have slowed Bismarck down even more?

[Tiornu]

I don't recall any instance of a shell hit causing a fuel tank to explode. As I recall, the lateral spray of splinters from a shell detonation travels only about two feet through a liquid. This might limit the increase in damage from a shell burst in a fuel cell.

[Bill Jurens]

The projectile probably did not explode, or if it did explode, it exploded low-order. It did cut through a transverse bulkhead, however. The passage of the shell, whether it exploded or not, did not involve any fuel tanks directly; these were two decks below. The forward fuel tanks were almost certainly rendered non-useable due to downflooding from above which either flooded them through slow infiltration from above (if empty) , or contaminated their contents with sea water. In any case, the transfer manifolds were submerged and/or damaged and could not be used to recover the fuel from the tanks.

Bill Jurens.

[Bill Jurens]

I made a few false statements in my last memo, which just goes to prove that it is always a good idea to check one's sources again before responding "on the fly".

As might be expected, the best descriptions of the damage forward were provided by Bismarck survivors.

The following quote is from "German Battleship Bismarck" -- Interrogation of Survivors", produced as a Confidential document by the British Admiralty in August of 1941. It is probably the most definitive (though perhaps not the most detailed) account we have. It is possible that some further details exist in the German literature, to which I have relatively little access.

At any rate, here is what the British found:

" One shell struck forward, entering the port side of Section XXI, at the height of the battery deck, above the waterline, and exploded on the starboard side, within the ship, at the level of the middle platform deck, making a hole in the ship's side 1 1/2 metres in diameter under water. The explosions damaged bulkheads between Sections XX and XXI, and Section XXI and XXII, and accordingly the three forward sections were flooded to a depth of 1 metre above the battery deck, the fore part of the ship sinking two or three metres. Oberleutnant (Ing.) Karl Ludwig Richter, second officer attached to the damage control centre, went forward to inspect the damage and took charge of repairs. The salvage pump room in SectionXX was flooded and so this pump could not be used. The salvage pumps in Section XVII were not very effective and only succeeded in pumping a little water from the three forward sections after the shell entry hole had been plugged and the exit hole had had a plate welded on to it from inside under water by a diver....... There was also a potential fuel shortage as forward fuel bunkers under Sections XX-XXII could no longer be used..... It had been thought that this shell went right through the ship."

This is an interesting account, and suggests that the projectile was deflected somewhat downward after impact, and probably entered at a fairly oblique angle with respect to the centerline. It is clear from the phrasing that Baron Rechberg's account was based on a reading of this particular passage, with some modifications, e.g. the suggestion that "matting" was placed over the holes rather than that the holes were plugged and/or welded shut. The Baron states that the ship slowed to about 22 knots while this was being done. I find it unlikely that the exit hole could have been welded shut underwater by a diver unless the ship were brought more or less completely to a halt, and in that regard, suspect that the diver actually welded some sort of grillage of tubing and bar over the hole in order to retain various and sundry packing materials. Even so, this would likely have been nearly impossible if the ship were steaming at any significant speed.

As there were probably few survivors who examined this area in detail anyway, and all of these individuals are probably now dead, these sorts of discrepancies are probably now more or less impossible to resolve.

Bill Jurens

[Tiornu]

Bill, have you calculated the amount of flooding caused by the hit to the turbo-generator room?
Can you explain the effects of free communication?

[Bill Jurens]

I have good official information on the tanks flooded by the hit amidships. Unfortunately, my source has requested that I not circulate this detailed data further.

So far as the amidships hit is concerned, as the hole in the shell would have been quite small, free communication effect would be quite small as well. As many of these spaces were not solidly flooded to the overhead, or at least were not continuously flooded to the overhead, free surface effect would have been much more important.

Bill Jurens

[José M. Rico]

have you calculated the amount of flooding caused by the hit to the turbo-generator room?

The electric plant No. 4 in the port side is approximately 9 x 7 x 3.5 meters. That gives a maximum enclosed volume of about 220 m³. To that figure add perhaps another 200 m³ for the wing fuel/void tanks and double bottom. Then we have to take into consideration the permeability of those spaces and the fact that they may have not been completely flooded to the top as Bill pointed out.

[Herr Nilsson]

The electric plant No. 4 in the port side is approximately 9 x 7 x 3.5 meters. That gives a maximum enclosed volume of about 220 m³. To that figure add perhaps another 200 m³ for the wing fuel/void tanks and double bottom. Then we have to take into consideration the permeability of those spaces and the fact that they may have not been completely flooded to the top as Bill pointed out.

To be more precise the electric plant No. 4 has a volume of 274 m³. Two fuel tanks with a volume of 43 and 129 m³. One void tank with 93 m³.
In the worst case this leads to a list of 2°, an immersion of 25 cm on bow and an emersion of 4 cm on stern. The port side would immerse about 74 cm, the port side emerse about 54 cm.

Source: Leakage tables "Battelship Bismarck "

[tommy303]

If I am not mistaken the shell which flooded out the port turbo-generator room burst near the bulkhead for the forward port boiler room causing tears in the bulkhead which eventually led to the loss of that boiler room as well. That being the case one might expect areas of the side defence system abreast the boiler room to flood out as well.

[Tiornu]

Yes, I believe that explains the reference to the fuel and void spaces. What we don't know is how much fuel was in those spaces or what changes there were in the bottom spaces.

[Herr Nilsson]

I made a few false statements in my last memo, which just goes to prove that it is always a good idea to check one's sources again before responding "on the fly".

As might be expected, the best descriptions of the damage forward were provided by Bismarck survivors.

The following quote is from "German Battleship Bismarck" -- Interrogation of Survivors", produced as a Confidential document by the British Admiralty in August of 1941. It is probably the most definitive (though perhaps not the most detailed) account we have. It is possible that some further details exist in the German literature, to which I have relatively little access.

At any rate, here is what the British found:

" One shell struck forward, entering the port side of Section XXI, at the height of the battery deck, above the waterline, and exploded on the starboard side, within the ship, at the level of the middle platform deck, making a hole in the ship's side 1 1/2 metres in diameter under water. The explosions damaged bulkheads between Sections XX and XXI, and Section XXI and XXII, and accordingly the three forward sections were flooded to a depth of 1 metre above the battery deck, the fore part of the ship sinking two or three metres. Oberleutnant (Ing.) Karl Ludwig Richter, second officer attached to the damage control centre, went forward to inspect the damage and took charge of repairs. The salvage pump room in SectionXX was flooded and so this pump could not be used. The salvage pumps in Section XVII were not very effective and only succeeded in pumping a little water from the three forward sections after the shell entry hole had been plugged and the exit hole had had a plate welded on to it from inside under water by a diver....... There was also a potential fuel shortage as forward fuel bunkers under Sections XX-XXII could no longer be used..... It had been thought that this shell went right through the ship."

This is an interesting account, and suggests that the projectile was deflected somewhat downward after impact, and probably entered at a fairly oblique angle with respect to the centerline. It is clear from the phrasing that Baron Rechberg's account was based on a reading of this particular passage, with some modifications, e.g. the suggestion that "matting" was placed over the holes rather than that the holes were plugged and/or welded shut. The Baron states that the ship slowed to about 22 knots while this was being done. I find it unlikely that the exit hole could have been welded shut underwater by a diver unless the ship were brought more or less completely to a halt, and in that regard, suspect that the diver actually welded some sort of grillage of tubing and bar over the hole in order to retain various and sundry packing materials. Even so, this would likely have been nearly impossible if the ship were steaming at any significant speed.

As there were probably few survivors who examined this area in detail anyway, and all of these individuals are probably now dead, these sorts of discrepancies are probably now more or less impossible to resolve.

Bill Jurens

Bill,

here's a quote from the PG KTB:

"May 24th
0950 hours-
Semaphore signal from Bismarck:
Commander to commander. For your information only. I have received two heavy strikes. One in compartement XIII-XIV. Hence, loss of generator 4, boiler room portside is taking on water, but can be contained. Second hit in compartement XX-XXI in forward ship section. Penetration portside, exit starboard above the armoured deck. Third strike through a boat without consequence. Otherwise I am fine. 5 light casualties."

I think this source is much more reliable than the British interrogation report.