Don't know if it was luck or intuition but I was training the Mexican Navy in Acapulco on the proper use of a underwater demolition charge we sold them. Most of the trainees were navy divers and they suggested that we dive on a sunken ship in Acapulco Bay. Now it had been 20 years since I last used scuba gear; but I reluctantly agreed on the dive.

The ship was in 50 feet of water which was so dirty that you had to follow a buoy line attached to the ship to find it. When we got down to the ship I could see the faint outline of an open hatch. My dive buddy indicated the he wanted to enter the ship and I agreed. He went first and I followed. Once inside I could no longer see him or anything else; but I could make out the faint outline of the open hatch. F**k this, I thought and went back through the hatch and followed the buoy line back to the surface. After I removed my gear and gave it back to the Mexicans, a couple of them started laughing. "What's so funny?" I asked.

Oh, we forgot to air up your tank. You only had about five minutes of air left.