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Originally Posted by Stormende
How often the batteries broke to the point that chlorine was present inside the sub and was not the anti gas masks enough to deal with it until the time to surface was better with no destroyers around?
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Chlorine gas is generated when sea water mixes with the acid inside the batteries. It is extremely deadly and only a very small amount can kill you. I do not have any data as to how often this occurred in the USN fleet boats, but theoretically it can happen anytime sea water gets into the battery well. I do know, however, that it was not a common occurrence.
The individual jars that contained the battery cells in the USN fleet boats consisted of an outer layer of hard rubber, then an impermeable membrane of soft rubber roughly the thickness of a toy balloon, then another layer of hard rubber. This was a very rugged construction that could flex with shock and not break. The membrane contained the acid and prevented leakage that could mix with sea water to create chlorine. This design was a tremendous improvement over the standard hard steel jar and was a key factor in the high survivability rate of the USN boats.
Quote:
Originally Posted by Stormende
Also I read somewhere that an electric sub is harder to detect by passive sonar than a nuclear, is it due to the reactor makes more noise or what?
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You are correct.
The prime source of radiated noise on a submarine is the propulsion plant. What drives a diesel-electric boat when it is submerged? Electric motors that are coupled to the propeller shafts. These motors are powered by storage batteries. Electric motors are virtually silent in operation, thus very little if any noise is radiated into the water.
What many people don't realize is that nuclear powered submarines are actually propelled by steam. The only thing the reactor does is provide an anaerobic (i.e. no air needed) heat source to superheat water in the primary loop. The primary loop provides heat to boil water in the secondary loop, generating steam. This steam then spins a turbine. This high speed turbine is connected to a set of reduction gears that in turn spin the propeller shaft. The water in both loops has to be moved through the system using pumps. So, in a nuclear plant you have three sources of noise: the pumps, the turbine, and the reduction gears. If not designed right this makes a heck of a lot of noise. The first American and Soviet nuke boats sounded like a freight trains barreling through the water. Eventually the twin practices of sound isolation mounting of machinery and extremely tight production standards largely mitigated this problem, but even today a well designed and tightly run diesel-electric boat can be just as quiet, and in some cases quieter, than a nuke boat when running on the battery. Of course, when running on the diesels it gets very noisy and this is its primary weakness.
Keep in mind that my description of a submarine nuclear plant is a very simplified one, but essentially accurate. There are several different designs out there. One eliminates the circulation pumps and moves the water around the loops using the natural heat convection of the water. Another substitutes the reduction gears for an electric generator which in turn supplies power to a motor on the shaft.
The USN has gotten so good at noise reduction that our modern boats are actually substantially quieter than the ambient noise in the surrounding ocean. That gives the word "silent" a whole new meaning!
