This is coolbert:
Flash! Solution to the problem of the air-independent-propulsion [AIP] submarine solved?
From a Strategy Page article as extracted even more germane than the Russian submarine fleet the threat as posed by the AIP submarine now better understood and greatly mitigated?
"Submarines: Noise From Russia"
"The U.S. has found that, given current sensor (sonar, magnetic, heat, chemical) technology it is possible to detect very quiet submerged diesel-electric sub. This includes the new ones one using AIP (Air-Independent Propulsion) systems that allow diesel-electric sub to stay under water, silently, for several weeks at a time. Since 2000 the United States has done a lot of work on improving systems used to detect submerged subs. This included lots of tests on diesel electric and AIP subs that led to many small tweaks to existing sensors on subs and surface ships. AIP boats, in particular, were found to have many vulnerabilities. The AIP technology generated more noise and heat than just using batteries for underwater propulsion. The more the U.S. studied AIP subs in operation the more ways they found these subs could be detected. The passive (listen only) sonar systems in the new Virginia class SSNs (nuclear attack sub) were tweaked considerably to better find diesel-electric and AIP boats"
With regard to noise as generated by submarines of the NUCLEAR PROPULSION VARIETY consider that an American Seawolf submarine creates while sailing only one/one-hundredth [1/100] the amount of noise as emitted by a Los Angeles class sub, the latter WHILE DOCKED!!
And the Virginia class nuclear sub even less noisier than the Seawolf? Amazing.
See previous blog entries regarding the AIP threat: