Rigid inflatable boats are mainly used for the rapid and flexible transport of offshore personnel and for rescuing castaways. Moreover, a fender system can be installed on the bow of a RIB to enable the boat to approach the access ladder of a wind turbine or accommodation vessel. Rigid inflatable boats can transport up to 10 people and more depending on their size. They reach speeds of between 30 and 50 knots (about 90 km/h) (depending on the specific design) and are usually propelled by outboard motors. The buoyancy of air tubes makes this type of vessel extremely seaworthy and allows it to be safely manoeuvred even in choppy seas. The hull usually consists of glass-reinforced plastic, aluminium or Kevlar. In addition, special lashing eyes makes fast retrieval and launching of the RIB by crane possible so that it can be stowed on board or offloaded from the deck of a field support vessel at any time.