Thru hull backing blocks

[Pedersen]

Bamboo is not suitable at all in boatbuilding - it rots and splits easily. As already mentioned, you also have to be very carefull with teak and epoxy. Because of the oil content it doesn't glue all that well and has to be prepared first. Plywood is fine of course and much cheaper.

[DefinitelyMe]

Originally Posted by Cheechako

Thinking out of the box;
Sooooo.... backing blocks started with wooden boats.... if fiberglass hull is 1"= thick or so.. do you really need them?
If you do need them, aren't they supposed to distribute the load wider than the seacock base?
Those Groco ones shown above don't really look much bigger than the seacock base..?
If you want load distribution... looks to me like a triangular seacock base should be avoided and would be better with the traditional round base....
If you use fiberglass blocks, glassed to the hull... what is the point? Concerned about breaking your hull when turning a stuck seacock?
BTW: I was able to see the 31 footer I built in 1981 summer before last. The one seacock I observed (Spartan) that I bedded on epoxied Marine play with 5200 still looked as new visually... hard to say I guess inside....

I'd have thought the hull would be perfectly strong enough on it's own if it is indeed 1" thick, but many modern hulls are not very thick at all. The extra thickness offered by the backing block provides more opportunity for a good seal, as well as strength, and also means that the inside of the boat is now flat rather than curved with the shape of the hull, so the seacock flange sits nicely on it.