The sub was found a year ago?! http://www.thaiwreckdiver.com/lagarto.htm http://en.wikipedia.org/wiki/USS_Lagarto_(SS-371)
don't forget that it is a difficult job. even today, they can't find the exact location of the four Japanese carriers near Midway. and those are a lot bigger and of those they got an (almost) exact location of the sinking. yep, it's a big ocean out there
True, although Bob Ballard did find USS YORKTOWN. Your point is a valid one, of course, and subs are quite small, as WW2 warships go.