Best choice for 45000 tons battleship

Discussions about the history of the ship, technical details, etc.

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Mostlyharmless
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Re: Best choice for 45000 tons battleship

Post by Mostlyharmless »

alecsandros wrote: ... Bismarck's powder magazines were not located in the same positions as US and Japanese battleships. The theoretical shell you are presenting would not hit the magazines.
Not to mention there were only 1 or 2 Type91 shells in the entire war that actualy worked as designed...
Note that I suggested the that the shell might hit one of Bismarck's shells. I agree that Bismarck's powder magazine were one deck up and behind the main belt and scarp. However, I suspect that an explosion in the shell room might easily send a flash into the powder magazines. Another possible disaster for Bismarck at Denmark Straits would be if a diving shell entered one of the forward engine rooms. That might either cause huge off centre flooding, probably disabling the armament until the list could be corrected, or take out two thirds of Bismarck's power. The point is that Bismarck would have been vulnerable to the shells that hit Tosa or Aki http://en.wikipedia.org/wiki/Japanese_battleship_Tosa. Admittedly, that shell misfunctioned by not initiating when it hit the water but a functioning Type 91 shell was designed to give that performance.

We don't know from WW2 battles how well the Type 91 shells were designed. The only time that an IJN battleship fired at a target on a near parallel course was off Guadalcanal and the range may have been too short for those shells to dive. At least one 8 inch seems to have hit after skipping.
alecsandros wrote: South Dakota's powder magazines were deep inside the ship and could not be reached by 8" or 14" APC shells at the ranges in existence during the second battle for Guadalcanal, even if they would perforate the main armored belt.
I specified the secondary magazines. My Google foo was not sufficient to find a diagram of South Dakota but http://hnsa.org/doc/plans/ has plans of USS New Jersey and page 10 shows the powder magazines on the third deck.
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Re: Best choice for 45000 tons battleship

Post by alecsandros »

Bismarck's magazines, both powder and shell, were situated higher within the ship than in most contemporary American and Japanese designs.

As you can see, there was very little room for a diving shell to reach either one by passing beneath the belt, considering a normal waterline.

We actualy DO know that the Type91 was a failure. There were tens of thousands of 8" - 18" shells fired in the war, and only 1 or 2 behaved as designed.
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Mostlyharmless
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Re: Best choice for 45000 tons battleship

Post by Mostlyharmless »

Matrose71 wrote:...snip...

To me there are two options.

A Battleship optimized for long range battle, so I would choose an enlarged SoD Class, with a longer hull and more speed, clearly advanced between 20000-30000yards or a Battleship more optimized for short to mid range battles between 15000-25000yards. Here I would choose a BS class with a shorter citadel and three triple turrets with the 40,6cm L52 (punch is to be replaced by nothing but more punch). If there is room for an other 1200ts, I would choose a 4 shaft design with a mixed machinery, 2 x 4 MAN 12 42/58 on the outer shafts with 73000 WPS and 8 Wagner boilers with two turbines on the inside shafts with 100000 WPS, so in summary 1730000 WPS, but more important 73000 WPS for Diesel cruising up to 24-25kn.
The problem with shortening Bismarck's citadel by having only three turrets is that the protected volume may become insufficient. Bismarck's main armour deck is one deck lower than Vanguards, so that Vanguard has more protected volume despite a shorter citadel.

A slightly slower Iowa could be built at 45,000 tons standard and would be a good choice for a long range battle. New Jersey's 1943 trials gave 29.3 knots at 163,400 shp and Iowa's 1985 trial gave 29.41 knots at 141,500 shp http://www.navweaps.com/index_tech/tech-104.htm, so even after shortening the hull we could probably get 30 knots with 180,000 shp. The only worry at long range is that a 41 cm Type 91 shell could possibly penetrate the 1.625 inch bulkhead low in the hull. Also, although not relevant to battleship versus battleship combat, Iowa's torpedo protection within the citadel was probably inferior to Vanguard's or Bismarck's.

I would like to add a vote for the Littorio rudder arrangement although it may reduce the speed and range. Next best is the American well separated double rudders.
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Re: Best choice for 45000 tons battleship

Post by Matrose71 »

The problem with shortening Bismarck's citadel by having only three turrets is that the protected volume may become insufficient. Bismarck's main armour deck is one deck lower than Vanguards, so that Vanguard has more protected volume despite a shorter citadel.
I'm aware of this problem, but I think a 150-155m citadel instead of 170m could be adequate. It is not optimal, but if we look how much reserve buoyancy BS created compare to SoD late war with 42000ts standard, I think you can built such a ship as compromise.

I have nothing against Vanguard, it was a very good ship, but I don't think the 15/42 was a optimal arnament for such a ship compare to other nations arnament and 45000ts. I'm not a fan of 4 x 2 turrets at WWII. Only a six gunner could to my opinion operate twin turrets, otherwise it is extravagance of steel, because of the too long citadel and one gun less.

My personal optimal KM ship in the 35000-37500ts range at 1935 wouldn't be SH/GN nor BS/TP. I would prefer an enlarged GN with 245m, 33m, 9,9m, 3 x 2 40,6cm L52 and the armour layout of BS (so 145mm upper belt and 110mm slopes, with a 150-155m citadel). To my own calculation it would be around 35000-36000ts, so I would also choose the mixed machinery and would end around 37500ts.
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Re: Best choice for 45000 tons battleship

Post by Thorsten Wahl »

The point is that Bismarck would have been vulnerable to the shells that hit Tosa or Aki
to support the diving shell vulnerability approach a comparative calculation(even approximate) could be useful. Say in comparison to Yamato and SoDak. Scetches welcome
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Re: Best choice for 45000 tons battleship

Post by Mostlyharmless »

alecsandros wrote:...snip...
We actualy DO know that the Type91 was a failure. There were tens of thousands of 8" - 18" shells fired in the war, and only 1 or 2 behaved as designed.
There were a number of battles during which Japanese cruisers fired 8 inch shells. The pre-war Japanese estimate was that diving shells (for battleships) would roughly double the danger space at long range. Thus success for the diving shells would correspond to the number of underwater hits roughly equalling the number of above water hits. Java Sea gives us one above water hit. We don't know what hits were scored at Sunda Straits. Savo Island was at short range and again we don't know exactly where all the hits went. Cape Esperance produced a single underwater hit on Boise and two above water hits on Salt Lake City. Salt Lake City was hit by five shells at the Komandorski Islands: “Incurred damage from three 8-inch projectile hits and two 8-inch shorts. Damage of a minor nature except for a hit which penetrated the hull just aft of after engine room and detonated in after fuel oil tank. An operating casualty caused temporary loss of steam.” from Summary of War Damage to U. S. Battleships, Carriers, Cruisers and Destroyers 8 December 1942 to 7 December, 1943. Empress Augusta Bay produced three hits, all duds and all (I think) striking above water. Thus we seem to have nine hits above water and three below suggesting that the IJN was too optimist at least as far as 8 inch shells were concerned. I have not found any non-Japanese below water 8 inch hits. Can anybody help?
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Re: Best choice for 45000 tons battleship

Post by alecsandros »

... At Samar alone, a conservative estimate gives 5000+ shells fired, of calibers 8" and above. None perforated the hull to destroy the ship from beneath the waterline, as designed. There was 1 heavy shell which exploded underneath the keel of USS White Plains, possibly 18", but it was a damaging near miss, and not a perforating-exploding shell. However, judging from US damage reports, at least 50 x 8" shells DID hit the US shps, but becase of their extra-long delays, very few actualy exploded, thus making damage far less devastating than it could have been if normal AP delays would have been used.
Gambier Bay succumbed after receiving over 40 x 8" hits...
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Re: Best choice for 45000 tons battleship

Post by Mostlyharmless »

Thorsten Wahl wrote:
The point is that Bismarck would have been vulnerable to the shells that hit Tosa or Aki
to support the diving shell vulnerability approach a comparative calculation(even approximate) could be useful. Say in comparison to Yamato and SoDak. Scetches welcome
I am not sure how to do calculations and I am incapable of producing diagrams but the Wikipedia article on Tosa states

“Another test conducted somewhere around this time involved a 406 mm (16.0 in) gun firing a shell at Tosa. It fell about 25 metres (82 ft) short of the ship, but continued through the water and struck the ship near frame 228, 3.3 metres (11 ft) below the designed waterline. The result was disturbing, as the shell was able to pass through the 76 mm (3.0 in) armor and explode in the port engine room.”

As usual for Wikipedia, the article isn't perfect. The gun was 41 cm and it passed through some thickness of structural steel – I don't know if it was 120 lb following RN practise or 75 mm after metrication had been completed. According to one poster elsewhere, the hole left in the hull suggested that the shell was significantly yawed when it hit. The normal explanation of the hit is that the fuse, which was derived from those of RN Greenboy shells, failed to initiate on striking the water but did initiate when the shell hit Tosa's structure.

“Kaigun” by Evans and Peattie http://books.google.co.uk/books?id=sYDr ... 24&f=false shows some illustrations.

As the shell hit 3.3 metres below the waterline and Bismarck's 170 mm armour only went to 2.2 metres below the waterline, an identical hit had the potential to seriously damage Bismarck assuming that 45 mm of Wotan Weich is not more resistant than 75 mm of 1922 HT steel.

By contrast, such a hit might even encounter Yamato's main belt and below that there is 270 mm tapering to 175 mm of CNC armour slopped at 8 degrees abreast the magazines and 200 mm tapering to 75 mm abreast machinery. South Dakota has a tapering belt which would have at least 6 inches of class B armour at 19 degrees at 3.3 metres depth. King George V would have at least 5.5 inches of armour (220 lb) of the lower belt at 3.3 metres abreast magazines and 4.5 inches (180 lb) abreast machinery.
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Re: Best choice for 45000 tons battleship

Post by Thorsten Wahl »

possible impact conditions of the Tosa test
distance 20000 m water entry 25 m before target dept 3,3 m could pentrate 76 mm (3") armor
possible velocity on water entry 495m/s AOF 17,5 degrees (according navweaps if the data is valid for WW1 shell too is unknown)

recommended impact conditions
at AOF 17 degrees travel distance up to 80 m relatively parallel to the surface
optimal distance at 40 m

at AOF 25 degrees max distance for hitting the target was 20-25m
-------------------------------------------------------------------------------------------------------------------------------------------
its far from trivial to derive the velocity at a certain point of the underwater (UW)-travel

At the first stage past water entry (roughly the first 10-15 m past water entry)
the projectile surface comes into contact with the water, the water flow at the projectile surface produces high pressure under the projectile and low pressur above the projectile, the projectile produces some buoyancy the trajectory therfor turns somwhat upwards. Projectile velocity is greatly slowed down by drag caused by contact with the water.

travel stage
After some time of the UW-travel a cavity was produced wich significantly reduces drag compared to the entry stage of the UW travel as the projectile survace mostly did not have contact with the water. In this stage the travel was relativly straight and velocity loss was relatively low.

final stage of the UW travel
If the velocity falls below a certain velocity the cavity collapses and the drag increases considerably again as ther was contact between the projectile and the water

If the projectile is optimised for underwatertravel the first stage is reduced
the better the shell is optimised for underwater travel- the shorter the entry phase -but the lower is the upturning moment.
Last edited by Thorsten Wahl on Fri Jun 13, 2014 7:27 pm, edited 2 times in total.
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Re: Best choice for 45000 tons battleship

Post by Steve Crandell »

alecsandros wrote:... At Samar alone, a conservative estimate gives 5000+ shells fired, of calibers 8" and above. None perforated the hull to destroy the ship from beneath the waterline, as designed. There was 1 heavy shell which exploded underneath the keel of USS White Plains, possibly 18", but it was a damaging near miss, and not a perforating-exploding shell. However, judging from US damage reports, at least 50 x 8" shells DID hit the US shps, but becase of their extra-long delays, very few actualy exploded, thus making damage far less devastating than it could have been if normal AP delays would have been used.
Gambier Bay succumbed after receiving over 40 x 8" hits...
I just finished Lundgren's new book on Samar, and IIRC there were several underwater hits there in which the IJN AP shells performed as designed. When they hit the ship directly, some of them started above the waterline and exited below it, which might actually be more damaging to the ship's survival than one which exploded. I believe there were other cases where the shell hit something substantial which stopped it, and then it exploded. He describes the behavior of almost every IJN shell hit in significant detail ... which bulkheads it passed through in which compartments, etc.
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Re: Best choice for 45000 tons battleship

Post by alecsandros »

Steve Crandell wrote:
alecsandros wrote:... At Samar alone, a conservative estimate gives 5000+ shells fired, of calibers 8" and above. None perforated the hull to destroy the ship from beneath the waterline, as designed. There was 1 heavy shell which exploded underneath the keel of USS White Plains, possibly 18", but it was a damaging near miss, and not a perforating-exploding shell. However, judging from US damage reports, at least 50 x 8" shells DID hit the US shps, but becase of their extra-long delays, very few actualy exploded, thus making damage far less devastating than it could have been if normal AP delays would have been used.
Gambier Bay succumbed after receiving over 40 x 8" hits...

I just finished Lundgren's new book on Samar, and IIRC there were several underwater hits there in which the IJN AP shells performed as designed. When they hit the ship directly, some of them started above the waterline and exited below it, which might actually be more damaging to the ship's survival than one which exploded. I believe there were other cases where the shell hit something substantial which stopped it, and then it exploded. He describes the behavior of almost every IJN shell hit in significant detail ... which bulkheads it passed through in which compartments, etc.
Hi,
As of 2011 , all original USN battle reports from Samar are available freee online, at bosamar.com

There were at least 200 shell hits scored by the IJN ships, with ZERO beneath the waterline as designed. Indeed, the level of detail of the reports is substantial.
You see destroyers there that were sunk after 30 or 40 8" and 14" hits. Do you think this was good performance of those shells ?
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