Bismarck vs. Iowa

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

Post by delcyros » Mon Jun 20, 2011 9:36 pm

I think Byron indeed made a good point. The max. firing rate for brief periods of action can be higher than 2rpm for the 16in/50 and 38cm for a good trained turretcrew and a stock of ready ammunition stored in the turrets back. At longer actions, when the stock of ready ammunition is used up, the capacity of the hoists and the speed to elevate up & down the barrels to loading position limit the cyclic firing rate. I know the figures for BISMARCK from her AVKS but does anybody know the figure for SOUTH DAKOTA´s or IOWA´s hoists?

Is that relevant? Maybe. In prolonged action neither ship is able to make use of the theoretical max firing rate during ranging period. But once straddled and rapid fire ordered a higher rate of fire indeed can come in handy.

dunmunro
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Re: Bismarck vs. Iowa

Post by dunmunro » Mon Jun 20, 2011 9:48 pm

delcyros wrote:I think Byron indeed made a good point. The max. firing rate for brief periods of action can be higher than 2rpm for the 16in/50 and 38cm for a good trained turretcrew and a stock of ready ammunition stored in the turrets back. At longer actions, when the stock of ready ammunition is used up, the capacity of the hoists and the speed to elevate up & down the barrels to loading position limit the cyclic firing rate. I know the figures for BISMARCK from her AVKS but does anybody know the figure for SOUTH DAKOTA´s or IOWA´s hoists?

Is that relevant? Maybe. In prolonged action neither ship is able to make use of the theoretical max firing rate during ranging period. But once straddled and rapid fire ordered a higher rate of fire indeed can come in handy.
Washington engaged Kirishima under the most favourable possible conditions for the maximum rate of fire. The target's range meant that the guns were being loaded and fired at almost exactly their loading elevation, the ToF was so short that corrections could be made without delaying fire, and the target was so dangerous that maximum incentive existed for the maximum RoF. BB ammo is so heavy, and the bagged propellant so dangerous, that no ready use ammo can be stored in the turret and certainly none is stored in the USN 16" triple turret. If Washington, with a highly trained and experienced crew, could not achieve 2 RPM, then it is almost certain that no other USN triple turret 16" BB could either.

Canyon.DS

Re: Bismarck vs. Iowa

Post by Canyon.DS » Wed Jul 11, 2012 3:42 am

I just found this forum and this is an intresting thread. no one seems to consider that most Battle ship armor was designed to deflect shells, but at a specific range. I'm not sure of the ranges, I think about 25 k yds or so. In one of the battles around the solomon Islands, American heavy cruisers, with 8" guns planned to approach battleships ( within about 14000 yds if memory serves) so their shells could penetrate the armor. Penetration is a matter of momentum, vs the tensile strength of the armor. Momentum ( a type of energy) is understood to be E=MV2 (energy = mass times Velocity speared) so you can see velocity is the most imporant part of the equasion. At closer range, firing 8" armor pearcing guns a cruiser (if it could survive the response) could penetrate the armor of Battleships. When you consider this then being able to hit at maximum range may not be the most important factor. What would the velocity of a 16" 50cal round be at maximum range, and would that be enough to overcome the strength of the steel of the armor. I have not even mentioned the angle of the armor, and the angle of the shell strike, as that is even more of a nightmare.

Having said this, I believe Iowa would win at any range, simply due to its more modern densign, and the history of the design of these ships and what was learned from their earlier generations (South Dakota, and North Carolina) Perhaps a more fair fight, ships as is during WWII would be a North Carolina vs Bismark. I still think the NC would win due to its vastly superioir fire control system. When expecting the outcome of a battle one cannot depend on luck (a la Hood sinking).

Interesting to add, Hood was not sunk due to lack of armor, it had more than some Battleships (in fact, by WWI standards, all of the "Fast battleships" of WWII could be considered Battle cruisers). Hood was sunk by taking a WWI armor designed system into WWII, where it had to face more accurate plunging fire than it was ever designed to. The ranges were relatively short, and i expect Prinz Eugin could have actually sunk Hood. It was delivering plunging fire, but for Bizmark to do this, shells would have had to be loaded with less powder, and therefore slower velocity, although I have never seen a record of the type of fire the Bizmark was using, as the gunnery and logs were lost with the ship, as far as I understand anyway.

Something to think about.

alecsandros
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Re: Bismarck vs. Iowa

Post by alecsandros » Wed Jul 11, 2012 6:09 am

Hi Canyon,

As you will dwelve deeper into the forum, you'll see that all the points you raised have been discussed several times.

You will find the schematics for Bismarck's fire control system, perforation limits for various shells and armors, and probabilities of hits at long ranges.

In short, Bismarck and Tirpitz were very powerfull units, and even though some numbers do not play in their favor [displacement, shell weight, speed, gun number], others do [rate of fire/minute, lower and smaller profile, vertical armor system, armor quality, % protected length/total length], with many others being comparable [radars and fire control system, secondary gun mounts, con tower protection] .
Thus, it could go either way; most likely it would be some small, non repeatable incident that would determine the outcome of the battle...

P.S: I don't think Hood was sunk by plunging fire, but by a peforating hit (or hits) through the main belt.

Thorsten Wahl
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Re: Bismarck vs. Iowa

Post by Thorsten Wahl » Wed Jul 11, 2012 6:41 am

plunging fire that kils the hood according to history channel note the almost freefalling projectile
http://www.youtube.com/watch?v=KUfN2hg8 ... re=related
see ~16:40-45
this documentation is full of flaws
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alecsandros
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Re: Bismarck vs. Iowa

Post by alecsandros » Wed Jul 11, 2012 10:48 am

Yes, "bad" Bismarck killed "poor and defenseless" Hood... :D

Byron Angel
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Re: Bismarck vs. Iowa

Post by Byron Angel » Wed Jul 11, 2012 11:46 am

alecsandros wrote:
P.S: I don't think Hood was sunk by plunging fire, but by a peforating hit (or hits) through the main belt.

..... Nathan Okun has postulated an interesting theory that, due to the large inclination of HOOD with respect to BISMARCK's line of fire at the time of the fatal hit, the projectile could have passed just over the main belt, pierced the armored deck over the engine room spaces, then pierced the unarmored after transverse bulkhead separating the engine room from the after magazine. We will never know for sure, but it is a plausibe theory IMHO.


B

Neil Robertson

Re: Bismarck vs. Iowa

Post by Neil Robertson » Fri Jul 13, 2012 8:47 pm

Yes, the hypothesis of Okun was also considered the most likely route for the hit that caused the destruction of Hood by the second enquiry into her loss. Offord was the ballistics expert and had to use estimates of the German 15 in shell weight and muzzle velocity based on Russian intelligence and what the British thought was the maximum possible performance for a 15 in gun. The British believed the range was 16500 yds but IIRC Okun used a figure nearer 20000 yds.

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