Thru-hulls, engine raw water intake, and others
- Thread starter mordust
- Start date
I recommend bronze for both the thru-hulls and proper bronze seacocks. I have no experience with plastic, so I can't comment further except that the bronze is stronger and will take abuse that plastic may not, both during installation and normal use. Why are you planning to replace the thru-hulls? I did replace the thru-hulls under my sink even though they were fine, as it turned out, but it was a pain (for access especially, had to remove the sink) because one of the original sizes was no longer available. I had to cut one of the thru-hull necks to get it out. I went forward with the replacement, but it may not have been necessary for all of them. If you can be careful in your application of force on removing the thru-hulls you may find they are fine and compatible with your choice of seacocks. You may find it a challenge to orient the seacock handles so that they don't interfere with each other. 
There's nothing wrong with removing the thru-hulls and inspecting them and then re-bedding them if they're OK.
I did not drill holes through the hull and the backing blocks to prevent the seacocks from turning after installation. Instead, I used 3/4 inch thick fiberglass plank for the thru-hull backing plates, which I then threaded for the proper diameter bronze hex screws. That totally avoided drilling 12 holes through the hull. The thick, hard backing block also reduces the chances you'll have to shorten the neck of the thru-hull to get it to seat.
Good luck with the project.
There's nothing wrong with removing the thru-hulls and inspecting them and then re-bedding them if they're OK.
I did not drill holes through the hull and the backing blocks to prevent the seacocks from turning after installation. Instead, I used 3/4 inch thick fiberglass plank for the thru-hull backing plates, which I then threaded for the proper diameter bronze hex screws. That totally avoided drilling 12 holes through the hull. The thick, hard backing block also reduces the chances you'll have to shorten the neck of the thru-hull to get it to seat.
Good luck with the project.
While the use of the word was probably unintended, please do not ever use plastic (as in cast resin) for valves connected to thru hulls.
Use either bronze or Marelon from Forespar. Both choices come in separate valves or the much-stronger one piece seacock assembly.
I slightly prefer the Marelon fittings, because they cannot suffer electrolysis. so that's what we have.
Ours are "bedded" to their backing plates and the hull itself by being installed with thickened epoxy rather than sealant. Once set, the outside 'lip' was ground off smooth, leaving the attachment base mounted permanently to the hull.
Prior threads:
ericsonyachts.org
ericsonyachts.org
And there are lots of other good threads on the subject.
Use either bronze or Marelon from Forespar. Both choices come in separate valves or the much-stronger one piece seacock assembly.
I slightly prefer the Marelon fittings, because they cannot suffer electrolysis. so that's what we have.
Ours are "bedded" to their backing plates and the hull itself by being installed with thickened epoxy rather than sealant. Once set, the outside 'lip' was ground off smooth, leaving the attachment base mounted permanently to the hull.
Prior threads:
E25 galley sink gate valve
I post this mostly out of curiosity. Below are pics of the gate valve and bronze thru hull that connect my E25 galley sink to whatever body of water she is floating in. Does this look original? Do you think the gate valve stem and perhaps the guts might have been replaced? Did it come in 1978...
seacock install
seacocks have mounting holes for through bolting but this doesn't make sense to me on a fiberglass install. 1- any impact would pull the head of the fasteners through the hull. Even with the blocking. 2-you have more exposed metal [the heads of the fasteners] with very little surface area in...
And there are lots of other good threads on the subject.