Groco BB-3 Flanged Seacock Backing Block Marine PVC Foam

The Groco BB-3 backing block enhances flanged seacock installations by providing a stable mounting surface between the valve flange and the hull. Constructed from marine-grade PVC foam, this backing block delivers reliable performance in the harsh marine environment.

Key Features:

• Versatile sizing fits multiple seacock flange configurations
• 1/2-inch thickness provides structural rigidity while maintaining enough flexibility to conform to minor hull curvature
• Pre-drilled holes accept threaded inserts for secure fastening to the hull
• Moisture-resistant construction will not swell or absorb water
• Environmentally friendly marine-grade PVC foam specially formulated for saltwater applications

Installation is straightforward: press threaded inserts into the hull-side holes that align with your seacock flange pattern. This creates a professional, secure mounting system that distributes fastener loads evenly across the hull surface and prevents leaks.