A life raft or ocean survival unit (1) is capable of self-righting upon capsize, even when occupied by one or more survivors. The life raft (1) comprises a hull-shaped ballast chamber (5) which fills with water upon inflation of the life raft and provides added stability to the vessel and in part see self-righting capabilities to the life raft. Water is sucked in through membrane valves located at the rear of the ballast chamber. The life raft also comprises a canopy (4) and inflatable base section (3), wherein the inflatable base section may be compartmentalised to prevent sinking of the unit in the event of a puncture deflation.