Here are my photos from the U.S.S. Grayling memorial and the U.S.S. Batfish, There is one photo of a plaque that says: "U.S.S. Grayling Submarine sunk here, telephone inside, is the only remaining piece from the Grayling it was a bouy system used during peacetim in case of an accident it would be floated to the top, it was removed during war. Also I have a picture looking from the bridge towards the bow on the Batfish, you can see the 20mm. Enjoy!
http://s148.photobucket.com/albums/s31/shoot-kill-win/