I've had very similar experiences sailing. Sleeping in a bunk, you get accustomed to the swooshing sound of the water running against the hull and the drone of

I've had very similar experiences sailing. Sleeping in a bunk, you get accustomed to the swooshing sound of the water running against the hull and the drone of an engine. After a few weeks, I was certain I could hear the radio on and knew the tune being played. I asked the crew members who brought the radio and they thought I was crazy. There was no radio. It was uncanny, i thought I heard the song word for word, almost note for note, but it was all in my head.