A real-world location fit for filling out your adventure; where norse icelandic fishermen suffered unthinkable conditions throughout frigid winters to harvest the fruits of the ocean.
In the summer there is a small stone jail for those who are caught breaking the rules of the Sorcery Springs Geyser Basin, but in winter they are imprisoned within the warm waters themselves. No bolts or bars are needed, the cold takes the place of prison walls.
It is not considered a crime if a ship's crew mutinies against a captain that is obviously unfit for the post (dangerously incompetent, insane, or overly cruel). Assuming, of course, that they can prove it.