Harpoon

A closed-room mystery is usually what the name implies. That is, the action takes place in a usually small, usually closed space, often with no clear path of escape. This is a bit like that but the room is a small boat and the escape route the wide ocean. Layer in a light-handed approach and a definite comedic bent to the horror genre and you have Harpoon. The official synopsis states: Rivalries, dark secrets, and sexual tension emerge when three best friends find themselves stranded on a yacht in the middle of the ocean under suspicious circumstances. When the engine fails the three friends face dwindling food and supplies. Tensions erupt and murderous secrets are exposed.