If you realy want to know what caused the S-5 to sink, and what the Navy did on the wreck, go to this site:
http://thesaltysailor.com/s-boats/salvrept.htm
I transcribed the salvage report from some very poor copies that Gary Gentile found in the National Archives back in the late 80's or early 90's. It is quite a good read when you consider what was known about decompression at the time and the fact that all the dives were made in Mark V heavy gear.
Also, look at the internal photo's for the S-4, I got those out of the Sub Museum in Groton CT.
Finaly, get a copy of "On the Bottom" by Edward Elsberg. It is the salvage of the S-51 and will curl your toes whith some of the diving exploits that they did, and lived to tell about.
Pete Johnson