Does anyone know where I can get blanking plates for Blakes sea cocks. I have 2 that are not connected to the heads anymore as I have had a chemical toilet for the last 10 years...
Don't think there is such a thing. If you leave them in, then have a short piece of hose with a wooden bung. Leave them closed, they are perfectly safe. If you want to remove them permanently, laminate over the holes on the inside, backfill the holes from the outside and finish off with glass cloth and epoxy. You won't see the repair as it will be covered with anti foul. If you still want to retain the option of re-fitting then make up your own blanking plates out of epoxy coated wood and use the bolts to hold in place - plenty of sealer as well.
Same thing. When I moved my engine inlet, I made up a blanking plate with big ply pad inside and cut a piece of wood with a hole saw to fit the hole, epoxying the two together. As the hull is sheathed ply I epoxied in place and finished outside with glass cloth and epoxy.
Bronze, although nice is OTT for this application. If I were doing it on a GRP hull, or a wood hull, I would make the same kind of blank. If I wanted to have it removable I would bolt it in or permanent, set it in epoxy.
I made a set for my ex loo - seacock holes from a piece of GRP sheet. I got my GRP when the boatyard was cutting up an unwanted boat. I used GRP about 3/16 in thick and made a plate for the inside and outside. The cavity I filled with sikaflex. Been in place for 7 years, now.