I can't speak for contemporary sailors, but I've read enough to know that historically, sailors to a man (yes, no women then--that was one of the rife superstitions) were extremely superstitious; in fact, that was expected. There existed so many superstitious premises that the list would be as long as my arm. I think, too, of the issue of inescapability: one can run out of a house or other building, jump out of a vehicle; but out at sea? Not so: stay on board, face the monsters, or jump overboard and drown.
Our protagonist Charlie--a professional gambler just a little too full of himself--won't be oceanbound, but he will be boarding ship--the WRONG ship. You see, Charlie has foolishly allowed himself to get into trouble on two fronts, and both involve his creditor, who's come up with a lovely idea by which to cancel Charlie's gambling debts--stay overnight on a supposedly spooky cargo ship.
Remember the old song "Good Time Charlie's Got the Blues?" Doesn't even scratch the surface of what our Charlie's about to encounter.