20 Surface of Working Decks
20.1 The surface of a working deck shall be non-slip. Acceptable surfaces are: chequered plate; unpainted wood; a non-skid pattern moulded into fibre reinforced plastic (FRP); non-slip deck paint; or an efficient non-slip covering.
20.2 A hatch cover fitted on a working deck shall have a non-slip finish.
20.3 In an inflatable boat or rigid inflatable boat the upper surface of the inflated buoyancy tube shall be provided with a non-slip finish.
21 Rails and Guards
21.1 Rails or equivalent protection shall be installed near the periphery of all decks of a vessel accessible to passengers or crew. Equivalent protection may include lifelines, wire rope, chains and bulwarks that provide strength and support equivalent to fixed rails. Deck rails shall include a top rail with the minimum height of 1000mm (39.5 inches) and lower courses or equivalent protection. The distance between the lowest course and the deck shall not exceed 230mm (9 inches) and the distance between the other courses shall not exceed 380mm (15 inches).
21.2 In a vessel fitted with a cockpit, which opens aft to the sea, additional guard rails shall be fitted so that there is no unprotected vertical opening, i.e. between vertical “members,” greater than 500mm in width.
21.3 In an inflatable boat or a rigid inflatable boat, handgrips, toeholds and handrails shall be provided as necessary to ensure the safety of all persons on board during transit and the worst weather conditions likely to be encountered in the intended area of operation.
21.4 Suitable storm rails or hand grabs shall be installed where necessary in passageways, at deckhouse sides and at ladders and hatches.
21.5 On a vessel authorised to carry one or more vehicles, suitable chains, cables or other barriers shall be installed at the end of each vehicle runway and temporary rails or equivalent protection shall be installed in way of each vehicle ramp when the vessel is underway.