Garboard Drain Plug Cast BronzeAttwood&';s Bronze Garboard Drain Plug reliably provides bilge drainage when hauling out, and it seals securely when not draining. It has machined and tapered pipe threads to ensure a watertight plug fit, and the nut can be removed with a wrench or pliers. This drain plug has a 3/8-inch neck depth and a A 1/2-inch NOT drain. It installs easily and securely using #8 screws in 3 countersunk holes.