Above water torp tubes on battleships?

[WelshZeCorgi]

There's a Naval Academy mission where you can put torp tubes on a battleship, can't remember which one right now. But didn't those need to be installed as close to the water as possible? I could put them anywhere, including the raised platform in the middle of the hull, where I guess to scale, the torpedoes would have to drop between 50-100 feet before reaching the water. I think this might be a bug, but if that was done in RL, I'll shut up. 

 

Edit: I also put X4 torp tubes in centerline mounts on a modern heavy cruiser, in the mission with modern heavy cruisers. I know these things were fired out of the tubes by compressed gasses, but being in the center of the wide deck of a heavy cruiser, it looked like the torpedo had to clear 20 lateral feet of ship (at least) in order to go over the side. Not sure if tubes could provide that much launching power, especially if you were launching 24in torpedoes. Feels like if you tried doing that on a real heavy cruiser, the torpedo would just bury itself into the deck in front of the launcher or just roll around like a loose cylinder.   

Edited January 8, 2020 by WelshZeCorgi

[disc]

It could be done, eventually, because aircraft torpedoes could be dropped from significant heights.

For a long time, though, torpedoes could not deal with high water-entry angles, or they weren't strong enough to drop from that high, so the above-water torpedo tubes were usually much closer to the water. On the Japanese cruisers Furutaka and Myoko, for example, a drop of about 20 feet was considered too much until the entry-angle issue was fixed -- when it was, the launchers were moved a deck upward. These technical limitations made high tubes ill-advised until after battleships largely disposed of torpedoes.

That, and a very high torpedo launcher produces a lot of topweight.

Whether it should be done, I do not know.

[Hellstrike]

1 hour ago, disc said:

That, and a very high torpedo launcher produces a lot of topweight.

How much top weight would a pair of triple launchers realistically add? Because I don't think that an armament similar to Scharnhorst's 1942 refit would be much on an issue on a 38000 ton battleship. I understand that a torpedo battleship would run into the issue you mentioned, but a launcher should not be heavier than a secondary turret.

[akd]

Direct detonation and local damage from hits on torpedo launchers needs to be modeled, rather than just adding to chance of post-penetration ammo detonation.

[disc]

On 1/6/2020 at 7:24 PM, Hellstrike said:

How much top weight would a pair of triple launchers realistically add?

The Japanese cruisers Tenryu and Tatsuta each carried two triple Type 6 21in (53.3cm) launchers.

The weight of each Type 6 launcher was 11.95 tonnes, totaling 23.9 tonnes. The weight of each Type 6 torpedo was 1432kg.

There were six torpedoes embarked, totaling to 8.592 tonnes. Each launcher with three torpedoes weighed 16.246 tonnes.

So, 32.492 tonnes grand total. Not a huge amount. A single Type 3 14cm/50 (5.5in) shielded gun weighed 21 tonnes.

Unfortunately it seems a lot of auxiliary equipment was needed for the torpedoes. A cursory look at the other Japanese cruisers indicates that this was usually the case -- lots of extra stuff needed. The total outfit weighed 88.8 tonnes on Tatsuta at 2/3 displacement.

Assuming that the 2/3 displacement did not include two torpedoes, the full load weight was ~91.7 tonnes.

Probably a minor amount for a big battleship like Scharnhorst or Tirpitz, but for the "bug" we're discussing, the weights would be very high (given the launchers were on top of the casemates), which is quite bad for stability, and the old pre-dreadnought hull would weigh much less proportionally.

[RAMJB]

On 1/6/2020 at 11:36 PM, disc said:

That, and a very high torpedo launcher produces a lot of topweight.

That's a quite minor problem with battleships with turrets weighing thousands of tons.

It was more a matter of displacement efficiency and damage control. Battleships from the end of WW1 were expected to fight at ranges well out of torpedo range - hence putting torpedoes on them seemed like both a waste of useful deck space and of useful displacement that could be used elsewhere on other features that actually were to matter in those long range encounters.

On the other hand there's the fact that having a (by force) largely unprotected set of extremely high flammable/explosive stuff wide open on your hull's deck in a ship designed to slug it out against other ships didn't look like the safest approach possible. A good hit on a deck torpedo launcher could set off their warheads, and the resulting detonation wouldn't probably be lethal for ships that big, but they would be enough to cause pretty sizeable craters on their former existing position. Which obviously wouldn't do very good things to the ship fighting ability (not to mention the safety of it's crew).

Both things mixed up meant that nobody bothered putting those things on battleships. We all know the germans kinda did with the Twins, Tirpitz, and later on the projected H designs - but the motivation behind those torpedoes was different as they were intended to be weapons against enemy transports for their raider role, saving main gun ammo (and main battery rifle wear) on ships that didn't justify main battery shell expenditure. And for all intents and purposes those mounts were actually wasted space and tonnage anyway even for those ships. So, there's that too.

Edited January 8, 2020 by RAMJB

[disc]

90 tons is 90 tons; the point is where. On the main deck? It is fine. Although I wholeheartedly agree with criticism of the German capital ships.

On top of the casemates, as this post suggests? Not so great, I expect. I think the game would give a pretty stiff penalty to roll characteristics for this. Mind, if a ship has too much stability, it will have a sharp, jerking roll -- very unpleasant -- so some topweight can be built in purposely, as on the Royal Navy's Revenge class.

Remember the issues the Americans had with WWII radars and AA guns -- they didn't weigh particularly much, but a few tons very high in the ship has cascading effects. Likewise the Japanese Myoko class. One pair of main deck quadruple launchers was removed to save weight during the war.

This is somewhat separate from the wisdom of torpedo tubes on a battleship, tactical or otherwise, but that is itself a valid question.

Edited January 8, 2020 by disc

[WelshZeCorgi]

I also put X4 torp tubes in centerline mounts on a modern heavy cruiser, in the naval academy mission rise of the heavy cruiser. I know these things were fired out of the tubes by compressed gasses, but being in the center of the wide deck of a heavy cruiser, it looked like the torpedo had to clear 20 lateral feet of ship (at least) in order to go over the side and into the water. Not sure if tubes could provide that much launching power, especially if you were launching 24in torpedoes or bigger. Feels like if you tried doing that on a real heavy cruiser, the torpedo would just bury itself into the deck in front of the launcher or just roll around uselessly like a loose cylinder.   

Edited January 9, 2020 by WelshZeCorgi