While heading down to San Juan Puerto Rico for AN/BQR 21 ops we started hearing a strange 60 cycle hum. Of course we were in the "Devils Triangle". We surfaced the boat, and Lt. Palmer had the CONN. He called down to the Torpedo Room on the 7mc and told me to bring a guy (I think it was Timmy Crum), 100 feet of air hose, two life harnesses,and an air grinder to the bridge. Mr. Plamer was convinced that the 60 cycle hum was coming from a ladder rung on the side of the sail. So we surfaced the boat, me and the other guy went to the bridge, the seas were rough as hell and Lt Palmer said he would be wave watch while I went over onto the sail plane and cut off the ladder rung. Over i went. I was just starting to grind off the rung when a wave washed me off the sail plane. I was hanging there when Lt Palmer said, "Look Out..Wave Coming!" Needless to say I was soaked. I finished cutting off the ladder rung, we went back down below, dove the ship and still had the 60 cycle hum!!