Paragraph 3

Construction. Each part of every liferaft launching appliance shall be such that when the appliance is operating under the working load and unfavourable conditions of list and trim it shall have an adequate factor of safety having regard to the material used, the method of construction and the nature of its duty. Except for lead sheaves and block sheaves, all parts of the appliance and its associated gear which are subjected to the working load, or on which the safety of the appliance or the liferaft while in the process of launching depends, shall be constructed of ductile material and no part, other than lead sheaves and block sheaves, shall be constructed of cast metal.