The Triangle
Actually it was decent. Not really a horror movie, more like suspenseful. For it to go the horror route they needed to spend more time compounding the isolation factor.
A lot of movies use isolation as a way to up the tension and hopeless feeling the victims find themselves in when there is no escape. Snowed in ski lodge, Artic outpost, underwater base, remote cabin in the middle of nowhere, etc... in this case it was an empty luxury liner on the ocean. That story line has huge potential, but no movie has quite pulled it off yet. Ghost Ship tried (and failed at the end)