[REQ] info on RL torpedo damage

[Arclight]

I'm interested in some data and opinions on torpedo damage on ships, in particular the size of the hole and the extent of damage beyond the area that was hit directly. Would damage be contained to the compartment it struck (let's assume it hitting midway between bulkheads) or would the bulkheads separating the compartment be likely to suffer damage as well?

Any chance of a torpedo striking on the bow or stern damaging the engines, maybe by transmission of vibrations?

How consistent is this damage? Would damage observed in 1 case be similar to damage observed on a ship of the same class with a similar hit, or would it vary quite dramatically?

[Sailor Steve]

Usually a hole from a torpedo is very large, and will span two or more compartments. Compartmentation on a modern ship will contain outboard sections that are smaller, just to help isolate the damage. Here is an account of the damage to SS Ohio, taken during Operation Pedestal, the supplying of Malta.

The Ohio was torpedoed amidships, were a huge pillar of flame leapt high in the air above mast height. Ohio seemed to be out of control; Captain Mason ordered the engines to be shut down, with all deckhands available putting out the fire with the deck water-lines. Lighted kerosene was bubbling up from the fractured tanks, while little gouts of flame spattered the deck on to a distance of thirty yards from the blaze. Fortunately however, the flames were put out and the tanker managed thirteen knots after being repaired. The blast destroyed the ship's gyro and brought the magnetic compass off its bearings, while the steering gear was lost, forcing the crew to steer with the emergency gear from aft.

A hole, twenty-four feet by twenty-seven feet, had been torn in the port side of the amidships pump-room. The blast had also blown another hole in the starboard side and the compartment was flooded. There were jagged tears in the bulkheads and kerosene was bubbling up from adjoining tanks, seeping in a film up through the holes in the hull. The deck had been broken open, so that one could look down into the ship. From beam to beam the deck was buckled, but the ship held together.

The whole story, including bomb hits and near misses (which also make holes in the hull, letting in more water) can be found here:
http://en.wikipedia.org/wiki/SS_Ohio

Unfortunately my copies of Conway's Warship series with pictures and descriptions of torpedo and shell hits are in storage at the moment, or I could give you a lot more information.

[THM]

I have a photo of the area after a torpedo hit somewhere. Gotta search it. Way different than just a hole. A lot of metal gets bend inward.
Bulkheads will fail if close by the point of impact. Either by direct explosive force or by rupturing due to physical forces like bending and tearing.

If the drive shaft gets damaged badly you are in a world of pain. Imagine a giant propeller shaft in a confined space torn free of its bearings...

Vibrations will cause damage. I recall reading that the German cruiser Ad. Hipper had to stop for immediate repairs somewhere between Scandinavia and England due to a faulty shaft bearing.

Water seepage will occur, too. After some time electric cables etc. will draw water like wick. Again, Hipper had to cut a lot of cables to fire control after some compartment down below had taken water to prevent massive shorts.

Cheers!

Chris

[alexradu89]

Since we're on the chapter of RL torpedo damage and such, could some of the more experienced guys tell us more of what depth should a torpedo be launched ? I had heard that the heavier the ship, the greater depth the torpedo must be launched, and what about weather, would rough seas affect torps launched at a small depth ?

EDIT: Here are some fantastic shots of HMS Thane's damage suffered from torpedo attack from U-1172. Just scroll down to the bottom of the page.

http://www.royalnavyresearcharchive....E_Gllery_2.htm

[Arclight]

A hole, twenty-four feet by twenty-seven feet, had been torn in the port side of the amidships pump-room. The blast had also blown another hole in the starboard side and the compartment was flooded. There were jagged tears in the bulkheads and kerosene was bubbling up from adjoining tanks, seeping in a film up through the holes in the hull.

Impressive story on the Ohio.

Pretty amazing that the force of the blast got directed straight through and out the other side.

So it's pretty safe to say that damage ranged far beyond the immediate area of the blast?

I know it's been said plenty of times, but the torpedoes in the game seem wimpy. Not by visual splash or damage value, but the area they affect. Hit the engine room in the center, and that's it, you take out that engineroom. What about, with a tanker or warship, the 2nd engineroom on the port/starboard side? Imho damage should be more widespread.

Thank you all for the replys, any more info is more than welcome.

[Sailor Steve]

A quick look through the "Allied Merchants Hit" section of www.uboat.net gives the following:

Medium Merchant (5590 tons):

torpedo struck on the port side just forward of the poop deck. The explosion opened a crack three feet wide across the deck, destroyed the interior compartments and flooded the engine room. The stern dropped 30°, apparently held in place by the shaft.

http://www.uboat.net/allies/merchants/ships/2220.html

15,000-ton liner took 1 torpedo to stop, but 3 more to sink, plus some shellfire.
http://www.uboat.net/allies/merchants/ships/739.html

A 10,000-ton tanker that also took 4 torpedoes to sink.
http://www.uboat.net/allies/merchants/ships/1843.html

15,500-ton liner sank after only one torpedo.
http://www.uboat.net/allies/merchants/ships/406.html

I know that sunk ships usually can't give proper damage reports, but I thought this would illustrate the variety of sinkings. I have info on a Japanese merchant that sank after being hit by a dud torpedo, and another that took 6 torpedoes and 10 hours of work by the submarine to finally put down.

[Bilge_Rat]

a typical U-boat torpedo had a warhead packing 280 kg (617 lbs) of TNT/HND/AL (a mixture of hexanitrophenylamine, trinitrotoluene and aluminum). That packs a lot of punch: