WW II Historical Thread, Discussion, Pics, Videos

[Jura The idiot]

...

Protected doesn't mean proof, or no damage. non penetrating hits still releases phenominal energy and create havoc even when not penetrating.

Sure. For example, during the Battle of Calabria I mentioned in a couple of my previous posts here, the 15" shell from the HMS Warspite went off upon hitting ... the funnel of Guilio Cesare (the second funnel, I mean the one more to the aft; a moment ago I consulted an Italian source but didn't find how thick it was, I only learned "fumaiolo" for funnel and saw the picture of the hole in it) and as far as I know just the ballistic cap got deeply into the ship, for example went through the wardroom heheh, anyway, the damage was substantial, as described, for example, here:

Please, Log in or Register to view URLs content!

quote,
Shrapnel from the shell causes several fires and the ready-use stowage of the nearby 37mm gun blew up. About two dozen sailors lay dead; many were wounded. The turbo fans sucked the thick smoke down into the engine room causing four out of eight boilers to be shut down. Speed decreased to 25 knots and within two minutes was down to 20 to then leveling at 18. Electrical power was lost to the entire ship for about 30 seconds.
end of quote

I think this would be called "mission kill" by American members of the SDF

 

[chuck731]

Sure. For example, during the Battle of Calabria I mentioned in a couple of my previous posts here, the 15" shell from the HMS Warspite went off upon hitting ... the funnel of Guilio Cesare (the second funnel, I mean the one more to the aft; a moment ago I consulted an Italian source but didn't find how thick it was, I only learned "fumaiolo" for funnel and saw the picture of the hole in it) and as far as I know just the ballistic cap got deeply into the ship, for example went through the wardroom heheh, anyway, the damage was substantial, as described, for example, here:

Please, Log in or Register to view URLs content!

quote,
Shrapnel from the shell causes several fires and the ready-use stowage of the nearby 37mm gun blew up. About two dozen sailors lay dead; many were wounded. The turbo fans sucked the thick smoke down into the engine room causing four out of eight boilers to be shut down. Speed decreased to 25 knots and within two minutes was down to 20 to then leveling at 18. Electrical power was lost to the entire ship for about 30 seconds.
end of quote

I think this would be called "mission kill" by American members of the SDF

A modern battleship has many parts that are not protected by heavy armor capable of resisting a battleship shell. Shells not penetrating heavy armor can still do following direct damage:

1. Hole the hull of the ship ahead and behind the main citadel, causing flooding, upsetting the ship's trim, reducing the ship's reserve buoyancy, disrupting transfer of fuel, and damaging non critical internal spaces.

2. Hole the ship below the armor belt in cases where the battleship's belt does not reach all the way to the bottom. This would include all German, British, Italian and French battleships. Only Japanese and American battleships had internal armor to protect against shells striking below main belt. This could penetrate into the engine room or the magazine, and can be every bit as catastrophic as a direct penetration of the armor citadel

3. Hole unarmored or lightly armored portions of the ship's super structure. Unfortunately due to weight restrictions such critical fire control observation instruments as the director and mast top range finders are always lightly armored, and can not withstand direct hits by heavy caliber shells. So hits here can seriously degrade a battleship's fire control. In case of WWII British battleships, the normal steering position and navigation bridge are also lightly armored. A hit here can kill critical personnel.

A non-penetrating hit on heavy armor can still do the following damage:

1. Dent the armor - a direct non penetrating hit often leaves a dent or depression on the armor. In cases where the hit is on the barbette that effectively make the circular structure out of round, and can jam the turret. It could also destroy any equipment immediately next to the armor.

2. Spall the back of the armor - a direct non penetrating hit deposits most of its kinetic energy into the armor and sends a compression wave through the depth of the armor plate. When the compression wave reach the backside of the armor it can cause extensive tensile failure inside the plate, causing large chunks of the armor plate to detach and fly around the protected space at high speed without actually leaving any holes that go all the way through the armor plate. This can be almost as dangerous as a penetrating hit. Usually a direct hit on the turret would cause spalling on the back of turret armor that can do enough damage in the confined space to disable one or more guns in the turret.

3. Crack the armor - a direct non penetrating hit may still cause the armor plate to crack from the point of the impact. If the armor has structural or load bearing function, as in many Japanese warships, this would destroy the armor's ability to continue to assist with the ship's structural integrity.

 

[chuck731]

I don't think we should focus too much on Kurita... lets say we have a more competent admiral like... Tanaka

But of course the Japanese were not in a good position at all.

It is a different question to ask about how 2 Yamato BB and 2 tone class CA on the one side, and 3 Iowa and 1 South Dakota class BB could best fight each other in the weather and sea conditions of Sumar, than to ask how the Sumar itself might have turned out if under prevailing tactical and strategic conditions, Japanese forces were to consist of these ships while American forces were to receive the addition of these ships.

I think the best way for these two group of ships to fight each other would be:

One the American side, maneuver to place squalls between Japanese and American lines, and seek to achieve and maintain a range of 15-20km, in order to be inside the inner edge of range zone where Japanese 18"/45 guns can penetrate American ship's 6" deck, while also inside the outer edge of the range zone where American 16"/50 guns can pierce Yamato's side belt.

American ships should also avoid placing Yamato and Musashi directly abeam, but instead should place Japanese ships as much as possible 45 degrees off bow or stern, in order to maximize obliquity of impacts from Japanese 18" shells against belt and bulkhead. This reduce the chance that 18" will penetrate if the belt or bulkhead is hit.

American ships enjoy numerical advantage in BBs, and can afford to ignore the Japanese CAs. The American BB should split up into 2 groups of 2 and each group should keep a different Japanese BB ships under fire. The Japense BBs would likely stay together and splitting American forces give Americans more leverage to dictate the direction of the battle, reduce Japanese force's ability to focus one one single American ship, and improve American line's ability to maneuver to position squalls between American ships and Japanese ships. Being under fire degrades the quality of fire control the Japanese ships can muster.

On the Japanese side, the 4 ships should stay together, fire should be concentrated on one American ship at a time, so as to exploit weaker protection of American ships and even the odds as soon as possible. The Japanese can certainly try to hit an American ship from beyond 30km and hope a deck penetration by an 18" shell would cause critical damage and thus even the playing field. But the chance of success is slim. The best range for the Japanese ships in terms relative armor penetration is 20km +. Above 20km the citadels of Japanese battleships are invulnerable, where as American ships remain vulnerable. But unfortunately real chances for hitting above 20km is not all that good, and at least one of two American groups would enjoy a massive speed advantage stand a good chance of closing to less than 20km before the Japanese score any major hits.

So the Japanese should maneuver themselves to maintain 20-25km range with the slower American group with a 27 knot South Dakota, while as much as possible reduce the rate of closure of the other American group with 2 33 knot Iowa class battleships.

 

[Jura The idiot]

...

American ships should also avoid placing Yamato and Musashi directly abeam, but instead should place Japanese ships as much as possible 45 degrees off bow or stern, in order to maximize obliquity of impacts from Japanese 18" shells against belt and bulkhead. This reduce the chance that 18" will penetrate if the belt or bulkhead is hit.

...

So you think those USN battleships should NOT have tried the "crossing the T" tactics, or I misunderstood? thanks

 

[chuck731]

Crossing T only works with large formations ships, or ships constrained by nearby land.

With 2 battleships, the Japanese can so easily avoid having their T crossed while their ships remain mobile and maneuverable. Also with just two ships, even if they are roughly in line ahead, they really won't mask each other's fire much. In any case, 9 gun battleships like all involved in this example lose only 33% of their firepower even when having their T crossed, so fighting from the down stroke of a crossed T is not nearly as big a disadvantage as if one had a line ahead formation of 10+ battleships masking eachother's fire and able to fire only half of their batteries anyway.

 

[Lezt]

So you think those USN battleships should NOT have tried the "crossing the T" tactics, or I misunderstood? thanks

crossing the T doesn't help much for small unit battles. crossing the T helps when you have amazing broadside potentials and very weak bow and sterns of wooden ships. Also, when you cross the T, the enemy ship on both side shield your ship from other enemy ship beyond them.

But with rotating turrets.. broadsides are no longer limited to the side arc of the ships and with armor plating which becomes very oblique when shot head on or from the rear, greatly enhancing their armor rating. Also the frontal profile of a ship is much smaller than the side profile of it.

So with a small squadron, crossing the T is not as useful.

It is a different question to ask about how 2 Yamato BB and 2 tone class CA on the one side, and 3 Iowa and 1 South Dakota class BB could best fight each other in the weather and sea conditions of Sumar, than to ask how the Sumar itself might have turned out if under prevailing tactical and strategic conditions, Japanese forces were to consist of these ships while American forces were to receive the addition of these ships.

I think the best way for these two group of ships to fight each other would be:

One the American side, maneuver to place squalls between Japanese and American lines, and seek to achieve and maintain a range of 15-20km, in order to be inside the inner edge of range zone where Japanese 18"/45 guns can penetrate American ship's 6" deck, while also inside the outer edge of the range zone where American 16"/50 guns can pierce Yamato's side belt.

American ships should also avoid placing Yamato and Musashi directly abeam, but instead should place Japanese ships as much as possible 45 degrees off bow or stern, in order to maximize obliquity of impacts from Japanese 18" shells against belt and bulkhead. This reduce the chance that 18" will penetrate if the belt or bulkhead is hit.

American ships enjoy numerical advantage in BBs, and can afford to ignore the Japanese CAs. The American BB should split up into 2 groups of 2 and each group should keep a different Japanese BB ships under fire. The Japense BBs would likely stay together and splitting American forces give Americans more leverage to dictate the direction of the battle, reduce Japanese force's ability to focus one one single American ship, and improve American line's ability to maneuver to position squalls between American ships and Japanese ships. Being under fire degrades the quality of fire control the Japanese ships can muster.

On the Japanese side, the 4 ships should stay together, fire should be concentrated on one American ship at a time, so as to exploit weaker protection of American ships and even the odds as soon as possible. The Japanese can certainly try to hit an American ship from beyond 30km and hope a deck penetration by an 18" shell would cause critical damage and thus even the playing field. But the chance of success is slim. The best range for the Japanese ships in terms relative armor penetration is 20km +. Above 20km the citadels of Japanese battleships are invulnerable, where as American ships remain vulnerable. But unfortunately real chances for hitting above 20km is not all that good, and at least one of two American groups would enjoy a massive speed advantage stand a good chance of closing to less than 20km before the Japanese score any major hits.

So the Japanese should maneuver themselves to maintain 20-25km range with the slower American group with a 27 knot South Dakota, while as much as possible reduce the rate of closure of the other American group with 2 33 knot Iowa class battleships.

I think that we agree the Japanese should turn away and plummet the Americans from long range - and try to even the odds by keeping south dakota away.

Yamato had a 27 knot speed, Iowas have a 33 knot. well, I think the opening salvo should be fired at 35 km or more. assuming a straight line chase for simplicity, a 5 knot advantage is a 9 km/hr closing speed. shooting at 35km will give the yamatos about an hour and half to shoot the iowas before the iowas can return effective fire.

1.5 hours, with 18 barrels at 1.5 RPM per barrel = 2430 shells (which is more than the ammo storage per barrel) if 1% hit... thats 24 18" shell hits. would that cripple the Us BBs to allow the Tones to torpedo them? I don't know... maybe not.

An interesting question is... how much can the theoretical float plane spotters help the Yamato's gunnery esp if this is just a battle ship scenario.

This would be an interesting probability exercise.

 

[chuck731]

crossing the T doesn't help much for small unit battles. crossing the T helps when you have amazing broadside potentials and very weak bow and sterns of wooden ships. Also, when you cross the T, the enemy ship on both side shield your ship from other enemy ship beyond them.

But with rotating turrets.. broadsides are no longer limited to the side arc of the ships and with armor plating which becomes very oblique when shot head on or from the rear, greatly enhancing their armor rating. Also the frontal profile of a ship is much smaller than the side profile of it.

So with a small squadron, crossing the T is not as useful.



I think that we agree the Japanese should turn away and plummet the Americans from long range - and try to even the odds by keeping south dakota away.

Yamato had a 27 knot speed, Iowas have a 33 knot. well, I think the opening salvo should be fired at 35 km or more. assuming a straight line chase for simplicity, a 5 knot advantage is a 9 km/hr closing speed. shooting at 35km will give the yamatos about an hour and half to shoot the iowas before the iowas can return effective fire.

1.5 hours, with 18 barrels at 1.5 RPM per barrel = 2430 shells (which is more than the ammo storage per barrel) if 1% hit... thats 24 18" shell hits. would that cripple the Us BBs to allow the Tones to torpedo them? I don't know... maybe not.

An interesting question is... how much can the theoretical float plane spotters help the Yamato's gunnery esp if this is just a battle ship scenario.

This would be an interesting probability exercise.

Yamato has only 100 shells per barrel, which is roughly standard for most WWII battleships. Japanese also believed 50 rounds per barrel is sufficient for a single engagement. So only 50 rounds are immediately accessible to the mechanized shell handling system. The rest must be moved from a reserve shell room in a process that takes several hours. Pre-war Japanese doctrine had been based in wildly over optimistic estimate of both shell and torpedo hit rate at extreme range.

So standing 35km off and firing continuously for 90 minutes in hopes of achieving a lucky hit is not a good option. Hit rate at that range is likely lower than what Japanese would need to achieve reasonable expectation of a single hit before expending their 50 rounds per barrel, and leave the Japanese in an awkward position for subsequent closer range battle.

The closest range where Japanese enjoy immunity from American shells is 20kms. This should be the range the Japanese aim for to maximize hit rate. At 20-25kms, it would be reasonable to expect ~2.5-5% % hit rate, which would give the Japanese the opportunity to score 10-20 hits between 2 ships with the readily available half of their ammunition supply. That is likely to be enough to seriously damage or mission kill 1 of the 4 US BBs. There after Japanese rate of fire will likely deteriorate sharply as shells must now first be moved from reserve shell room into the turret rotating structure before it could be accessed by the mechanized loading system.

There are other nuances to difference in shell loading arrangement between US and Japanese battleships. In the Yamato, the entire ammunition supply (for the first ~450 rounds) is fully mechanized. No muscle power is involved. The system is designed to provide constant rate of fire with the ship rolling up to 10 degrees, beyond 10 degrees rate if fire falls off sharply as the system of horizontal shell transfer works against slope.
US battleships, unique amongst WWII battleships, use manual, mechanically assisted human muscle power to move the shells from storage to shell hoist by par buckling. The system works better than might be imagined, and offer competitive rates of fire at least initially. But its performance falls off with ship roll sooner than would with a fully mechanized shell handling system. Also American rate of fire is likely to suffer from crew muscle fatigue after prolonged firing, while Japanese mechanized system still functions at designed rate.

But American system has the entire 100 round per gun ready for firing. Yamato's system has only 50 rounds ready for efficient loading.

 

[Jura The idiot]

...

I think that we agree the Japanese should turn away and plummet the Americans from long range - and try to even the odds by keeping south dakota away.

I beg to disagree. The Yamato-class was a strategic weapon, expected to be superior in the decades to come ("superior" in the sense of being armed with, and partially protected against, the biggest naval guns of 1940s and likely up to 1950s; now I quote from p. 178 Conway's Fighting Ships 1922-1946: "Protection was designed to give immunity against 18" shells between 22000 and 33000 yards, and against a 1 ton bomb dropped from 15000 feet.") My point is they (I'm talking about a task force consisting of Yamato and Musashi) should have been used aggressively to get close to ANY battleship force of 1944 and ride it down Things wouldn't be that easy, I know, considering for example the American fire-control; in this respect I quote from

Please, Log in or Register to view URLs content!

"This was a much better performance than other contemporary systems, and gave U.S. battleships a major tactical advantage, in that they could both shoot and maneuver, whereas their opponents could only do one or the other."

Yamato had a 27 knot speed, Iowas have a 33 knot. well, I think the opening salvo should be fired at 35 km or more. assuming a straight line chase for simplicity, a 5 knot advantage is a 9 km/hr closing speed. shooting at 35km will give the yamatos about an hour and half to shoot the iowas before the iowas can return effective fire.

1.5 hours, with 18 barrels at 1.5 RPM per barrel = 2430 shells (which is more than the ammo storage per barrel) if 1% hit... thats 24 18" shell hits.
...

You quote maximal speeds. I doubt Yamato, Musashi would have achieved 1.0 percentage of hits at high speed (25+ knots) at long range (25+ kilometers).

 

[Lezt]

Yamato has only 100 shells per barrel, which is roughly standard for most WWII battleships. Japanese also believed 50 rounds per barrel is sufficient for a single engagement. So only 50 rounds are immediately accessible to the mechanized shell handling system. The rest must be moved from a reserve shell room in a process that takes several hours. Pre-war Japanese doctrine had been based in wildly over optimistic estimate of both shell and torpedo hit rate at extreme range.

So standing 35km off and firing continuously for 90 minutes in hopes of achieving a lucky hit is not a good option. Hit rate at that range is likely lower than what Japanese would need to achieve reasonable expectation of a single hit before expending their 50 rounds per barrel, and leave the Japanese in an awkward position for subsequent closer range battle.

The closest range where Japanese enjoy immunity from American shells is 20kms. This should be the range the Japanese aim for to maximize hit rate. At 20-25kms, it would be reasonable to expect ~2.5-5% % hit rate, which would give the Japanese the opportunity to score 10-20 hits between 2 ships with the readily available half of their ammunition supply. That is likely to be enough to seriously damage or mission kill 1 of the 4 US BBs. There after Japanese rate of fire will likely deteriorate sharply as shells must now first be moved from reserve shell room into the turret rotating structure before it could be accessed by the mechanized loading system.

There are other nuances to difference in shell loading arrangement between US and Japanese battleships. In the Yamato, the entire ammunition supply (for the first ~450 rounds) is fully mechanized. No muscle power is involved. The system is designed to provide constant rate of fire with the ship rolling up to 10 degrees, beyond 10 degrees rate if fire falls off sharply as the system of horizontal shell transfer works against slope.
US battleships, unique amongst WWII battleships, use manual, mechanically assisted human muscle power to move the shells from storage to shell hoist by par buckling. The system works better than might be imagined, and offer competitive rates of fire at least initially. But its performance falls off with ship roll sooner than would with a fully mechanized shell handling system. Also American rate of fire is likely to suffer from crew muscle fatigue after prolonged firing, while Japanese mechanized system still functions at designed rate.

But American system has the entire 100 round per gun ready for firing. Yamato's system has only 50 rounds ready for efficient loading.

Minor corrections, the yamato had 100 round per gun, 60 rounds are immediately accessible in the cassette, 40 in the shell room.

Here is a nice animation of the yamato's turret hoist system: (I think Japanese engineering students.. have too much time and catia/solidworks on their hands..

Please, Log in or Register to view URLs content!

Here is one on the Iowa's gun training video.

Please, Log in or Register to view URLs content!

 

[Jura The idiot]

Yamato has only 100 shells per barrel, which is roughly standard for most WWII battleships. Japanese also believed 50 rounds per barrel is sufficient for a single engagement. So only 50 rounds are immediately accessible to the mechanized shell handling system. The rest must be moved from a reserve shell room in a process that takes several hours.
...

chuck731 are you absolutely sure it was 50:50? I quote from Campbell (end of p. 179): "Of the total of 100 per gun, 60 were stowed in the shell handling rooms in the revolving structure, and 40 in the shell room on the same level as the lower handling room, that is immediately below the main armour deck in 'B' and 'Y' and a deck lower in 'A'. In action, the guns would be supplied from the lower handling room and then from the upper one. Transfer from the shell room by push-pull gear and shell bogie was slower than supply by the hoists so that the handling rooms would be replenished between actions. It may be noted that the upper handling room could be filled only via the lower room and auxiliary or main hoists." end of typing