Washington Naval Treaty Fails

This doesn't make much sense to me. What's so important about the torpedo bulkhead? We know that heavy shells penetrated and exploded in the engineering spaces:

This requires a penetration of the belt or the main armour deck. You state that the main armour deck was just below the waterline, which would be a problem, as perforation of the upper belt would allow flooding to spread out across the top of the main armour deck and to enter the turbine and boiler rooms via the shell holes.

Actually, http://www.kbismarck.com/proteccioni.html states that the main armour deck was actually about a meter above the waterline, but maybe the combination of flooding from POW's hits, counterflooding to correct the list, subsequent damage in the final battle and the heavy seas had reduce that meter of clearance to the extent that flooding could occur freely through the heavy shell holes into the citadel. In any case, it seems clear that gun penetration of the torpedo bulkhead isn't important. Of course, this doesn't tell us anything of the significance of scuttling attempts, but it does suggest that gunfire had significantly decreased Bismarck's buoyancy and stability.


It should also be noted that HMS Rodney did close in on Bismarck to some 2000 yards only, fireing at this point blanc range full broadsides into her target. As the 16 inch shell was fired from such a close range, it would hit Bismarck's side at almost straight angles, as the guns of the British ship did not even need to elevate. Even if Bismarck had her sides protected by 30 inch armor, this would not have been enough. At this close proximity the AP shell's used would penetrate any armor.
 
It should also be noted that HMS Rodney did close in on Bismarck to some 2000 yards only, fireing at this point blanc range full broadsides into her target. As the 16 inch shell was fired from such a close range, it would hit Bismarck's side at almost straight angles, as the guns of the British ship did not even need to elevate. Even if Bismarck had her sides protected by 30 inch armor, this would not have been enough. At this close proximity the AP shell's used would penetrate any armor.

The key point here of course is that by this time Bismarck was dead, unable to defend itself. ;)

Steve
 

sharlin

Banned
But what he's putting paid to is the myth that the bismarks belt was not penetrated. At 3000 yards the Rodney would be able to put a round through the face of the Yamato's turrets.
 
Bismarck had numerous problems, that she had only 3 shafts decreased her manoeuvrability, and put extra stress on her already weakened (there was a propeller shaft going through it after all) rear keel, not helped by the overly-long stern. Likewise, her mixed secondary/AA armament poor fire computers were what actually allowed the Swordfish to get in and out mostly without loss.

She was also spreading an oil-slick, a present from the Prince of Wales who'd managed to land one right on her forward fuel line, which reduced her speed to about 20 knots.
 
This doesn't make much sense to me. What's so important about the torpedo bulkhead? We know that heavy shells penetrated and exploded in the engineering spaces:
The main armour belt is designed to stop shells, but the torpedo protection system behind that (And below the WL) is designed to stop torpedo impacts from flooding any vital area (Such as engine rooms). It was a system of tanks (Fuel, water and empty ones for counter-flooding) in Bismarck, and was backed by a 45mm Wh steel bulkhead and extended from the bottom plates to just above the main armour deck. Now, the objective of the anti-torpedo system is obvious - To stop a tinfish penetrating into a vital area of the ship, but in Bismarck's case it would mean that if that bulkhead was not breached, then no substancial flooding of the inner armour citadel would take place, and in all warships, the inner armour citadel is designed to provide enough bouyancy so that if the whole ship outside of this area is free-flooding, the vessel will stay afloat - Providing said citadel itself is not breached. With the torpedo bulkhead intact, no flooding was occuring inside Bismarck's machinery spaces through enemy hits at or below the waterline.

Reference: Anatomy of a ship. P 16,17.

This requires a penetration of the belt or the main armour deck. You state that the main armour deck was just below the waterline, which would be a problem, as perforation of the upper belt would allow flooding to spread out across the top of the main armour deck and to enter the turbine and boiler rooms via the shell holes.

Actually, http://www.kbismarck.com/proteccioni.html states that the main armour deck was actually about a meter above the waterline
My apolagies there. The drawing in Anatomy of the ship is not the biggest scale, so I must have mis-read it. I will defer to kmbismarck and the location of the main armour deck. I should have said around the waterline really ;)

but maybe the combination of flooding from POW's hits, counterflooding to correct the list, subsequent damage in the final battle and the heavy seas had reduce that meter of clearance to the extent that flooding could occur freely through the heavy shell holes into the citadel. In any case, it seems clear that gun penetration of the torpedo bulkhead isn't important. Of course, this doesn't tell us anything of the significance of scuttling attempts, but it does suggest that gunfire had significantly decreased Bismarck's buoyancy and stability.
Yes, flooding and counter-flooding would reduce the level of the armour deck above the WL, leading to flooding. I found a good sketch somewhere demonstrating that. I'll see if I can find it.

Here we are. It was the IJN Kirishima's Damage analysis document (pfd) from after the wreck was located. Pages 17-21. Basically, it shows that even if a warship's torpedo bulkheads and main armour decks are intact, progressive flooding can sink her if the there is damage to structures that run into these areas (Funnel uptakes for instance), as the more the ship floods outside the citadel, the lower these become, until they are below water.
 
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