[djmcmath]

Some interesting points being made here, and a lot of confusion. Fastpat, I think that your confusion about submarine employment (both by US and ROW forces) is an interesting point in itself. The Submarine Force on the whole is a very quiet bunch by nature. It's the Silent Service, except that we're so silent, nobody knows what we're up to. It's a bit of a quandary facing the Sub Force...

Some unclassified things that may be of interest ... the new diesel boats are very impressive platforms. Some of them are incredibly quiet, and carry extremely modern weaponry -- on par even with the US torpedoes. Like Seahawk says, active sonar is an excellent way to geolocate such a platform. Extremely low frequency active, as I noted above, and which is the original topic of this thread, is pretty silly, however. Even higher freqency active is becoming a less preferred method with the advent of some useful tools to counter it. Currently, the best way to find any submarine is to listen for it -- classic passive sonar. (Well, not quite "classic" passive sonar -- we've come a long ways since WWII...) A lot comes down to the training and experience of the crew, which is generally a reflection of the force as a whole. For example, it is well known that submarines from a certain country routinely make loud noises caused by crewmembers doing stupid things -- we'll say dropping hammers, leaving bits of metal in free-flood areas so they rattle when the boat moves, that sort of thing. Such a submarine is easy to find -- but it takes little more than crew training and attention to detail to transform such a boat from "impossible to miss" to "impossible to find."

Diesel boats present an interesting threat. Such a platform is more than capable of carrying and delivering an arbitrary weapon of choice to anywhere they'd like. While many of the older boats are very limited in speed and range, the newer boats are far more capable. A submarine threat capable of delivering a warhead of choice to anywhere in Europe or Asia has been a longtime reality. Submarines capable of (and interested in) delivering to the US are becoming an increasing likelihood.

The question for you, Pat -- how many nuclear warheads landing on US soil would it take to constitute an "attack?"