A valve for use with a vessel drain tube includes a body extending along a longitudinal axis. The body has an outer surface and an inner surface defining a bore extending longitudinally from a first end to a second end. The valve includes an external seal on the outer surface of the body for sealing with the drain tube, at least one internal seal on the inner surface extending into the bore, a retaining member extending at least partially into the bore and being spaced from the internal seal, and a sealing member displaceable between the internal seal and the retaining member. The sealing member is configured to seal with the internal seal in a valve closed, first configuration and to not seal with the internal seal in a valve open, second configuration.