[SgtWalt65]

One submarine, the USS Pampanito was back in 1986 ( not sure if it still is, and likely is not ) was a museum, but was being maintained by the US Navy at that time and still ran on the surface only. I went aboard her and to my suprise found two Naval Officers onboard in the locked out portion of the ship. I got one of thems attention ( Chief petty Officer, dont recall name ) and asked him what they where doing. He explained to me that the ship was not on the navy register, but was still maintained by the US Navy and was used as a training sub for new submariners. In xplaining he told me on occasion it was taken out into the Bay ( not the Pacific ) and they conducted training on it. Also said it could NOT be submerged due to the metal fatique over the years and they where not sure it could handle the pressure of being submerged. However all systems at this time still functioned. The reason they where there was for some repair work on electronics ( ie radio and radar ) and some other equipment checks prior to a new training class scheduled to come aboard.
This was 21 years ago, so most likely not the case anymore.

Side note: Its also funny how select Navy pilots are trained in the North American P-51D Mustangs in Florida. Never have figured that one out.
Info: http://www.stallion51.com/