What about the closed-cycle diesel-electrics now in the sub fleets of France, GB, Germany, Australia, Sweden? I understand they can run their diesels while submerged, using liquid oxygen. It would seem that these subs would be formidable opponents, as they can stay down for several weeks, and be totally silent for fairly long periods.
mrblue92 wrote:
It didn’t capsize but the USS Chopper did go vertical by the bow and stern:
http://www.geocities.com/Pentagon/Quarters/9928/deepdive.htm
The Chopper was decommisioned as a result of the damage suffered in the accident.
Andrew Warinner
I just read Heinz Schäffer’s U-Boat 977. Schäffer and his crew decided to split for Argentina from the North Sea after the surrender of the Germans. Because they were so vulnerable to naval radar when surfaced, they ran submerged for something like fifty-five days, relying entirely on the Shnorchel (I think that’s how Schäffer insisted it is spelled), with a damaged periscope. This one of the first known prolonged submerged voyages.
Schäffer specifically deals with how dangerous it was for an inexperienced crew to learn how to use the Shnorchel. When waves blocked the air intake, the enormous twin diesels would draw air out of the interior of the boat almost instantly, causing massive pressure fluctuations that would injure sailors’ eardrums. At the same time, diesel exhaust would back up and blow itself into the boat, instead of out.
After seven weeks of this sort of thing, mold and mildew had become so prevalent that almost all flat surfaces were green and fuzzy. And to cap it off, these guys finally show up in Argentina and get accused of dropping of Hitler, Eva Braun, and Martin Bormann in Antarctica. Golly, sometimes it just sucked to work for the Nazis.
Yep, that’s a good book. I likely the part where the one Nazi thought they were still going to win late in the war and offerred Schaffer the chance to come see a demostration of the death ray they were working on.
Oh, and actually he calls the snorkel a “Snort”, saying it was frequenting misspelt “Schnorkel”. (pg 101 in my very old copy)
Nuclear subs can be traced to a general location by using thermal imagers on satellites.
The water which is used to cool the core has a differant temperature to the seawater around it, only by a few tenths of degrees but it’s enough.
Diesel electrics are very quiet indeed and their main role, you guessed it, is hunting nukes.
Passive sonar can be effctive at ranges over 200 miles so a general location might be good enough to allow such a hunter/killer to get on the case.
That only works if they’re near the surface, right? I’d imagine that a sub at 200 meters would have an undetectable, if any, effect on sea surface temperature.
I’ve heard that the navy was working on detecting submarines via the portion of the wake that reaches the surface. Is this true/possible? I also remember seeing an article in Science that mentioned the detection of centimeter-sized changes in surface terrain by satellite during the construction of a subway tunnel in Italy (? …maybe; I don’t have the reference handy so I could be wrong). Are these two things related?
Actually some of the newer nukes, such as the Seawolf and the Ohio class FBM’s do not necessarily have to have any pumps running at all in the reactor machinery while underway.
They designed the containment capsule to be tall and narrow so that as long as they are moving slowly convection will cause enough water movement to cool the reactor. If they want to go faster though they have to turn on pumps to move enough water through the system to keep temperatures in the core low enough for safety. This means that the newer nuke boats can be pretty much as quiet as a diesel/electric boat at low speeds. Which they would be at if they were hunting another submarine.
A US Navy Admiral was quoted as saying that the Seawolf is as quiet at 15 knots as a Los Angeles class boat is while it’s tied along the pier. I’m not sure what the max speed is using convective cooling, they keep that pretty close to the vest. 
Kevin