5.3.4(d) Arrangement of suction pipes. Bilge suction piping system is to be sized in accordance with 4-6-4/5.5. For drainage when the vessel is listed (see 4-6-4/5.3.1), wing suctions will often be necessary, except in narrow compartments at the ends of the vessel. Arrangements are to be made whereby water in the compartment will drain to the suction pipe.