Yes, the episode was “Not Guilty” in the second season. Apparently all the passengers on the Minnow had a motive to kill someone who was shot to death with a spear gun.
So the gang acted it out, and figured out that the spear gun went off by accident when a door was slammed.
My question, too, is how come he had the speargun loaded and cocked when he began to “clean” it. Or do they mean that he was getting ready to clear the speargun (which I still would have expected him to do while still on the boat, or into the sand at the beach). Had he just tied up the boat and the wife happened to be standing there?