A deck mounted for installation on the surface of a vessel deck having one or more bolt holes. The apparatus includes one or more base portions, each having a recess region defined by a perimeter wall bounding the perimeter of the base portion. The perimeter walls each have an underside rim. One or more threaded members are provided for insertion through the bolt holes in the vessel deck, and complementary threaded female members are provided, one each to receive and tighten onto a threaded rod. A resilient gasket is disposed in the recess region within the confines of the perimeter wall. The threaded rod passes through the gasket hole, such that when the threaded rods are inserted through the vessel deck, and received by and tightened into the respective threaded female members, the gaskets are displaced and deformed so as to protrude between the underside rims of the perimeter walls and the upper surface of the vessel deck.