Abstract: A roof structure is adapted for removable attachment to a boat permitting use of the roof as an emergency float for boat occupants. The roof includes a shell having a buoyant member affixed thereto with an inflatable ring carried on the shell in a collapsed manner. A source of pressurized air is in controlled communication with the inflatable ring. Roof support structure includes lug equipped plates on the boat and the roof which, upon roof repositioning, permits separation and launching of the roof. A modified form of root support structure includes deck mounted, swingably mounted upright supports located adjacent the roof sides and which permit lowering of the roof into the water. The inflatable ring contributes to buoyancy as well as occupant protection from the water.