hammocks on ships

My dad was in the US Navy during World War II. He went on active duty when he was 19 years old in 1943. His time was spent on ships called LSTs that delivered supplies, and, at the end, brought prisoners of war back to their homes.

The oceans can get quite choppy.  He told us the crew slept in hammocks. While the ship tossed about, hammocks stayed relatively stable. The ship rocked even on calm seas, but the men in the hammocks did not.