If you knew anything about torps you'd know that they run on some sort of power, this is created by liquid gases (to provide Oxygen) and other great stuff (for fuel). Each of these are just as volatile as the warhead itself, and are actually calculated into the exploding force of a torpedo. Some of the chemicals used in torps are also not too compatible with salt water (ie, the ocean) and the smallest drop could result in a massive explosion. Also saltwater is very corrosive it will corrode many parts of torps if in contact long enough and these parts can be under extreme pressure or protecting voilatile material.

If you remember back a few years to the Russian Sub Kursk investigation showed that the explosion (first one) was caused by a leaky Hydrogen Peroxide tank that was used to supply the kerosene burning motor with oxygen. Hydrogen Peroxide is EXTREMELY volatile (esspecially in a compressed state) and lack of maintenacne caused it to go off, the resulting secondary explosions (war heads and fuel tanks of near by torps) destroyed the kursk.

The Bismark and Hood still have unexploded shells on them don't they? imagine the bang if one of them goes off!

Actually they were powered (at least the steam ones) by a catalytic reaction which in turn created heat which in turn created steam.

Once "spent" the reagents are done and more or less neutralized.

Even without its warhead and even if the propellant tanks are empty a torpedo is still big heavy hunk of metal that can still do a lot of damage.

Which brings us back to the question.

How in the hell did it float ?

Usually they don't, but sometimes the buoyancy tanks survive, probably in less than 1% of cases. The default peacetime setting is for the torpedo to float for recovery, in wartime this is changed to explode or sink. Most peacetime ones that are lost will eventually sink, but there are always going to be the exceptions to the rule.

As a lurker of these awsome forums I finally speak. This has been an interesting thread for me.

Recently I watched a documentary on the U-864 that was sank off of Norway by the Brit sub Venturer. It is not so much the ordinance that is of concern but the 65 tons of mercury that she was carrying.

I have read a couple articles implying that the Germans used mercury for levelling off the boats faster. This particular Uboat was heading to Japan with the mercury (along with rocket parts and scientists, not gold and Hitler's last will and testemant).

A verry interesting tale for sure. Ran aground by an inexperienced skipper, repaired, then engine problems that made her a sitting duck for Commander Jimmy Launders and the Venturer crew. Firing four fish at the sounds of the damaged U-boat and hitting with only the fourth one.

http://www.iht.com/articles/2007/01/11/news/norway.php

http://www.spiegel.de/international/...455652,00.html

Just saw a news report that they just found an old German torpedoe floating around in the Baltic near the town the G8 summits going to be held later this year

http://www.news.com.au/story/0,23599...-38200,00.html

It is the only time that one sub destroyed another while both were submerged.