ISO 6185-4:2011 specifies the minimum safety characteristics required for the design, materials, manufacture and testing of rigid inflatable boats (RIBs) with a hull length of between 8 m and 24 m and with a motor power rating of 15 kW and greater. It is applicable to Types IX and X of RIBs intended for use within the operating temperatures of -20 °C to +60 °C. Type IX: Powered boats, fitted with a buoyancy tube covering at least 85 % of the port and starboard sides, suitable for navigation in inshore and sheltered waters, up to and including wind force 6 Beaufort and significant wave heights up to 2 m (design categories C and D), with a hull length of between 8 m and 24 m and with a motor power rating of 15 kW and greater. Type X: Powered boats, fitted with a buoyancy tube covering at least 85 % of the port and starboard sides, suitable for navigation in waters, up to wind force 8 Beaufort and significant wave heights up to 4 m (design category B), with a hull length of between 8 m and 24 m and with a motor power rating of 75 kW and greater. It excludes single-chamber boats, boats of less than 1 800 N buoyancy, and boats made from unsupported materials of more than 12 kN inflated buoyancy and powered by motors of power exceed