The Thread of Flame — Basil King

Without opening my eyes I guessed that it must be between five and six in the morning. I was snuggled into something narrow. On moving my knee abruptly it came into contact with an upright board. At the same time the end of my bed rose upward, so that my feet were higher than my head. Then the other end rose, and my head was higher than my feet. A slow, gentle roll threw my knee once more against the board, though another slow, gentle roll swung me back to my former position. Far away there was a rhythmic throbbing, like the beating of a pulse. I knew I was on shipboard, and for the moment it was all I knew.