Bronze Through Hulls and Seacocks in Steel Boat

[Pauls]

Critique on the design:
1. In addition to the nitrile you show as a gasket/insulator on the thru hull flange you will need an insulator around the body of the thruhull.
2. The current design is fully dependent on the adhesion of the FRP plate to the hull. That is unacceptable. A better design is a steel mounting plate welded to the hull and threaded (blind holes) to take the mounting bolts for the valve.
3. UHMW is an excellent insulator, easily available and easy to work with.


Regarding some of the above posts, galvanic corrosion requires an electrical connection between the different metals AND immersion in a concutive liquid. If the thru hull is fully insulated from the hull (test it with an ohm meter) then there will be no galvanic corrosion.