The Severn class lifeboat is the largest lifeboat used by the Royal National Lifeboat Institution (RNLI), a UK charity dedicated to saving life at sea. The class is named after the River Severn, the longest river in Great Britain. There are forty-six Severn class lifeboats serving the RNLI around the coast of the UK and Ireland since the introduction of the class in 1996. It carries a Y Class inflatable boat, which can be deployed by an on-board crane for use in shallow water. Severns have a comprehensive electronics fit including full MF and VHF DSC radio equipment, DGPS Navigator, an electronic chart system, VHF/DF, radar and weather sensors. For added manoeuvrability, in addition to twin engines, the Severn also has a bow thruster fitted. The propellers are enclosed so the Severn can take ground without damaging them. The Severn is constructed of fibre reinforced composite material, and the hard chine semi-displacement hull built to a two compartment standard, meaning it can stay afloat with two of its five compartments flooded. Provision for survivors includes comprehensive first aid equipment including stretchers, oxygen and Entonox. Severns carry a portable salvage pump in a water-tight container, and can also carry out pumping and fire fighting tasks using the engine driven general service pump.