- A rigid-hulled inflatable boat, (RHIB) or rigid-inflatable boat (RIB) is a lightweight but high-performance and high-capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale. The design is stable and seaworthy. The inflatable collar allows the vessel to maintain buoyancy if a large quantity of water is shipped aboard due to bad sea conditions. The RIB is a development of the inflatable boat. Uses include work boats (supporting shore facilities or larger ships) in trades that operate on the water, military craft, where they are used in patrol roles and to transport troops between vessels or ashore, and lifeboats.