46 CFR 160.017-11 - Materials.
(a) Suspension members. Each suspension member of a chain ladder must be a continuous length of non-kinking chain, such as single loop lock link coil chain, with a minimum breaking strength of at least 16 kN (3,560 lbs.).
(b) Metal parts. Each metal part of a ladder must be made of corrosion-resistant metal or of steel galvanized by the hot dip process after the part is formed. If the ends of galvanized fasteners are peened over to lock them in place, a corrosion resisting surface treatment must be applied to each peened surface.
(c) Wooden parts. Each wooden part of a ladder must be made of hardwood that is free of defects affecting its strength or durability.
(d) Wood preservative. After each wooden part is formed and finished, it must be treated with water-repellant wood preservative that is properly applied.
(e) Lashing rings. The inside diameter of each lashing ring must be at least 75 mm (3 in.). Each lashing ring must have a minimum breaking strength of at least 16 kN (3,560 lbs.).