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 ½-inch NOT drain. It installs easily and securely using #8 screws in 3 countersunk holes.