I was 19 when I volunteered for the U-boat fleet in 1942. I thought it was my duty. I went through basic training in Bordeaux — the U-boat pens there were massive, underground, concrete cathedrals. I made four patrols. On my fourth, in April 1944, a British frigate dropped a pattern of depth charges that shook us so hard that three of our crew urinated involuntarily. We could hear the steel hull screaming. The order came: 'Dive to 280 meters.' Our maximum rated depth was 200. We went to 280. The boat held. We escaped. I later learned that 75% of U-boat crews were killed during the war — the highest casualty rate of any branch of any army in the war. I survived 54 months of that. After the war, I couldn't be in enclosed spaces for years. I couldn't sleep without a window open. Even now, at 97, I can't sleep in a bed — I sleep on the floor. Something about being at floor level, away from the ceiling. I think it's about not wanting to be trapped above.