The rigid buoyant boat (RBB) is a light-weight but high performance and high capacity boat. Based on the concept of a Rigid-hulled inflatable boat (RHIB), it has a tube/sponson manufactured from a solid material such as moulded polyethylene or aluminium and therefore being much more robust than the fabrics commonly used. Boats with foam filled collars such as the secure all-around flotation equipped (SAFE) boats employed by the US Coast Guard can also be classified as Rigid Buoyant Boats rather than "true" RHIBs as the collar is solid foam rather than inflated. The handling tends to be very similar to a RHIB; likewise they will remain afloat (buoyant) even if completely flooded. Aluminium RBBs tend to be bespoke (custom-made to specification) or low-volume products whilst the tooling cost