Este é Berço Superior por F. Marion Crawford. É muito famoso como histórias de fantasmas antigos, e tem sido em dezenas de antologias de terror. É exatamente como você descreveu - um homem no mar dormindo em um lugar mais baixo está perturbado durante a noite, embora não tão mal quanto seu companheiro de quarto no berço superior:
I was sleeping soundly when I was suddenly waked by a loud noise. To judge from the sound, my room-mate must have sprung with a single leap from the upper berth to the floor. I heard him fumbling with the latch and bolt of the door, which opened almost immediately, and then I heard his footsteps as he ran at full speed down the passage, leaving the door open behind him. The ship was rolling a little, and I expected to hear him stumble or fall, but he ran as though he were running for his life. The door swung on its hinges with the motion of the vessel, and the sound annoyed me. I got up and shut it, and groped my way back to my berth in the darkness. I went to sleep again; but I have no idea how long I slept.
When I awoke it was still quite dark, but I felt a disagreeable sensation of cold, and it seemed to me that the air was damp. You know the peculiar smell of a cabin which has been wet with sea water. I covered myself up as well as I could and dozed off again, framing complaints to be made the next day, and selecting the most powerful epithets in the language.