Bismarck and Iowa

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
spicmart
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Re: Bismarck and Iowa

Post by spicmart »

Combat results
-the UW protection/TDS-Double bottom wasnt impaired by the 2 ton charges of the X-Crafts. despite beneath/nearby explosions Nevertheless the ship was rendered off duty due to massive shock damage.
But there was some flooding I guess?
dunmunro
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Re: Bismarck and Iowa

Post by dunmunro »

spicmart wrote:
Combat results
-the UW protection/TDS-Double bottom wasnt impaired by the 2 ton charges of the X-Crafts. despite beneath/nearby explosions Nevertheless the ship was rendered off duty due to massive shock damage.
But there was some flooding I guess?
There was some flooding but Tirpitz was saved by the fact that she was moored in ~120 ft deep water, and the charges were resting on the bottom. This meant that there was ~90ft of standoff distance between the charges and the hull bottom. At Alexandria, QE and Valiant were moored in less than 50ft of water and the charges were only ~15ft from the hull bottom.
paul.mercer
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Re: Bismarck and Iowa

Post by paul.mercer »

Dave Saxton wrote:
Rick Rather wrote:
Dave Saxton wrote:The German 38cm gun could penetrate 130mm of Wh deck at 30,000 meters. The Iowa's decks protection is 140mm worth of, in my opinion, a slightly inferior material. Once past 30,000 meters the angle of fall of the 800kg projectile increases at rapid rate, due to it carrying less momentum down range than if it was heavier. This means that deck penetration increases quickly with greater range. By 32,000 meters it is exceeding 150mm deck penetration and by 36,000 meters it is exceeding 200mm deck penetration, according to one source.

For the same reason of the 12000kg 16" projectile carrying more momentum down range, steeper angles of fall are delayed until greater battle ranges, causing it have virtually the same deck penetration as the West Virginia's lighter 2240 lb 16" projectile per range. The penetration does not exceed 130mm (of in my opinion a slightly inferior material) until 30,000 yards, and does not exceed 150mm until 34,000 yards.

A Bismarck could certainly challenge an Iowa at long range.
That's assuming that they could hit the Iowa at long range. The consensus in this thread is that such hits were very, very unlikely. In it, you wrote,
Dave Saxton wrote: So max practical range late war in day light could be defined by the effective range that radar could range the target and spot the fall of shot. However, radar doesn't change the low probability of scoring hits at such ranges due to ballistic reasons. In most cases I'd say the max practical range in excellent conditions, late war, was about 30km (33,000 yards) for all combatants.
and
Dave Saxton wrote: It's probably not by tactical circumstances alone that BB59 did its shooting within that radius at Casablanca. The BB to BB range of its FC radars was also about 27,000 yards but since the radars were knocked out by gunfire shock right at the start of action that probably wasn't the reason. One notes that the 1945 BB59 gunnery doctrine reads 27,000 yards as extreme range.
OTOH, see my sig line (below). :wink:
In the past I have been rather zealous in pointing out the improbability of consistently scoring hits at plus 30km range, not because it is not possible, as it is possible and the Germans proved it, but to counter the unrealistic, and impractical, fantasies that exist on the internet of such unlikely combat scenarios, at least for WWII.

Often, the underlying assumption is the Iowa class could, but their potential opponents could not.
Gentlemen,
I think that we agree that while scoring hits at long range is possible given the right conditions and a fair amount of luck, however surely a hit at that range does not necessarily mean that the shell is going to penetrate a vital area or do a tremendous amount of damage - it must depend on where it hits and even at a closer range there is no guarantee that any shell no matter how good, will hit a particular part of a ship and cause serious damage- although I grant that a 15/16" shell will hurt no matter where it lands.
spicmart
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Re: Bismarck and Iowa

Post by spicmart »

Thorsten Wahl wrote:
@spicmart: Bismarck's torpedo defense system was rated to withstand 250kg of TNT, expectation was that damage inwards of the TDS from larger explosions would be contained rather than prevented - Bismarck featured extensive subdivision. The rating seems quite conservative; German assumptions of the time were generally pessimistic.
-Bismarcks TDS it was full size testet against 300 kg S1 (Schießwolle 36) wich was significantly stronger than TNT.
The TDS remained watertight.
Did they test it at the weakest spot, where the torpedo bulkhead has the smallest distance to the outer hull (3m) that is? It's where the turrets and magazines are.
dunmunro
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Re: Bismarck and Iowa

Post by dunmunro »

spicmart wrote:
Thorsten Wahl wrote:
@spicmart: Bismarck's torpedo defense system was rated to withstand 250kg of TNT, expectation was that damage inwards of the TDS from larger explosions would be contained rather than prevented - Bismarck featured extensive subdivision. The rating seems quite conservative; German assumptions of the time were generally pessimistic.
-Bismarcks TDS it was full size testet against 300 kg S1 (Schießwolle 36) wich was significantly stronger than TNT.
The TDS remained watertight.
Did they test it at the weakest spot, where the torpedo bulkhead has the smallest distance to the outer hull (3m) that is? It's where the turrets and magazines are.
Scharnhorst's TDS was hit at a point where the TDS narrowed and it failed against a 750lb TNT torpedo warhead. Bismarck's magazines were high enough in the ship to be safe from torpedo hits, although the shell rooms below might suffer flooding.
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