Physical Danger
Brace yourself for what's coming, for aside from the glaringly obvious physical danger of falling into the middle of the roaring sea, there are about a million other ways to harm yourself as a sailor.
Cutting yourself with any number of sharp tools? Check. Falling down a ladder onto an exceptionally hard wooden deck? Check. Getting crushed by moving cargo? Frighteningly enough, check. One false move and you're in for a world of hurt.
Did we forget to mention the unpredictability of the sea itself? Storms can seem to come from nowhere, tossing your ship around like a toy boat in a bathtub and creating a whole new set of potential dangers.
And here's the kicker: should any of these events occur, keep in mind that you aren't exactly hospital adjacent. Let's just take a second and do that math: a plethora of ways to get injured on the job, minus proper medical care, equals one seriously dangerous work environment. So if you're going to injure yourself, do it while the ship is docked―it's way safer that way.