11.1.1 Intact stability: All boats
11.1.1.1 The boat shall have sufficient stability and buoyancy considering both its design category (see 4.2.1) and the maximum recommended load specified on the capacity plate.
11.1.1.2 A range of realistic and relevant loading scenarios, including ‘worst cases’ must be considered. Conditions must include the following:
• Maximum load condition specified on the capacity plate i.e. maximum crew and survivors, full fuel, engine, all operational on-board equipment etc. • Lightest condition as permitted by the operating manual
• Any intermediate case that may be worse for any reason • Any other operational considerations that might affect stability
11.1.1.3 Fuel free surface moments should be minimised as far as possible by design. 11.1.1.4 Intact and damaged stability tests can be carried out with the engine and fuel
tank either installed or replaced with an equivalent mass. Each crewman may be substituted by a representative mass (see Para 11.1.6) and each survivor by 90kg for the purpose of the tests.
11.1.1.5 Intact and damaged stability tests are to be carried out on the boat whilst floating in still water and should be witnessed by the Rescue Boat Organisation and a Competent Person. Stability Calculations are to be verified by a Competent Person.
11.1.1.6 If a boat is completely in accordance with a standard production type certificates of approval may be provided and considered for any tests already completed. However personnel weights appropriate to Rescue Boats as specified in Para 11.1.6, or appropriate corrections, must have been applied.
11.1.1.7 All intact stability information must be included in associated documentation. 11.1.1.8 If a boat wishes to operate in Operational Limit Category B waters (as defined
in 4.2.1, noting 4.6.2), it should also adhere to wind heeling and wave requirements set out in ISO 12217-1 - Sections 6.3 and 7.
11.1.2 Intact Stability: Rigid Hull Boats
11.1.2.1 Rigid hull boats of hull length greater than or equal to 6m should comply with the stability requirements of ISO 12217-1.
11.1.2.2 Rigid hull boats of hull length less than 6m should comply with the stability requirements of ISO 12217-3.
11.1.2.3For all rigid hull boats, and for each condition specified by Para 11.1.1.2, all personnel up to the maximum number of persons for which the boat is certified (except the Helmsman, who may be assumed to be at the steering position) should be crowded to one side, with half this number seated on the side deck. This procedure should be repeated on the other side and at each end of the boat. In each case, the following must be addressed:
• Positive stability must be maintained
• The angle of heel and the position of the waterline should be recorded • The freeboard to top of the gunwale must never be less than 250mm at any
11.1.3 Intact Stability: Inflatable Boats, RIBs and Boats with a Buoyant Collar
11.1.3.1 For each condition specified by Para 11.1.1.2, personnel up to the maximum number of persons for which the boat is certified (except the helmsman, who may be assumed to be at the steering position) should be crowded to one side, with half this number seated on the buoyancy tube. This procedure should be repeated on the other side and at each end of the boat. In each case, the following must be addressed:
• Positive stability must be maintained
• The freeboard to the top of the buoyancy tube should be recorded
• The freeboard should be positive around the entire periphery of the boat, including the transom, unless the boat complies with Para 12.3.2
• The boat should not display an inherent tendency to lift the buoyancy tube and loss of stability due to wind pressure under the buoyancy tube should be determined
11.1.3.2 Static stability tests must include a factor of safety to take account of the influence of wind, waves etc.
11.1.3.2.1 An appropriate number of additional people may be added to leeward to simulate an additional worst case wind heeling moment. By calculation a 40 knot wind heeling force generates a 14-degree heel on a 7.5m RIB. This equates to 2 crew, each of 100kg, on the buoyancy tube.
11.1.4 Intact Stability: Survivor Recovery – All Boat Types
11.1.4.1 Referring to the realistic operating scenarios generated in Para 11.1.1.2, positive stability must be maintained throughout the process with an appropriate number of crew (the Helmsman may be assumed to be at the steering position) recovering one, two (or more) persons from the water. The operational validity of the number chosen must be demonstrated. The rescued persons should feign to be unconscious which can be defined as ‘not being able to help oneself’, with their backs turned to the boat so as not to assist the rescuers. Each person involved should wear an approved lifejacket. If dummies are used, they must be of an appropriate weight.
11.1. 4.2 Survivor recovery heel tests should be carried out on the boat whilst floating in still water.
11.1.4.3 Survivor recovery tests in Para 11.1.4.1 should be repeated for the boat in a fully swamped condition – see Section 11.2.
11.1.5.1 The following options are available to determine the maximum number of persons allowed on board the Rescue Boat:
11.1.5.1.1 As a guide, ISO 6185 Parts 1 to 4 contains a formula to determine the maximum number of persons allowed on board an inflatable boat. However person weights specified below, in 11.1.6, must be substituted into this formula. ISO 14946 also provides guidance.
11.1.5.1.2 The intact and damaged stability requirements of this Code must be satisfied, which may be used to determine the number of persons allowed. This may result in a reduction in the number of persons allowed by ISO 6185 Parts 1 to 4.
11.1.5.2 The maximum number of persons on board will be determined by the lesser of Paragraphs 11.1.5.1.1 or 11.1.5.1.2.
11.1.6 Crew and Survivor Weight Definitions
11.1.6.1 For calculation purposes the weight of a fully equipped and dressed Rescue Boat crew member is assumed to be 100kg.
11.1.6.2 It is recognised that in certain instances e.g. surf rescue crews equipped with minimal PPE, this average weight could be assumed to be less: if so, the Rescue Boat Organisation may approve on an individual basis a lower figure (to a minimum of 85 kg).
11.1.6.3 The weight of an adult survivor and passenger is assumed to be 90kg, the weight of a child survivor is assumed to be 37.5 kg. A reduced weight for passengers may be considered (to a minimum of 75kg).
11.2 Swamping and Drainage