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Discussion Starter · #1 ·
My first big project on my little boat!

The Catalina 22 was built with a garden-hose style valve glassed directly to the hull for the sink and cockpit drain. I'm replacing it with a bronze thru-hull.

This might be mass overkill for a tiny boat that will be sailing on a tiny lake, but one of my goals with this boat is to learn how to do things The Right Way so I'll have the experience for future, larger boats.

So I've got a printout of Maine Sail's instructions, and a big pile of 1" bronze hardware:



Any tips, tricks, or advice?
 

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Discussion Starter · #3 ·
The G10 plate arrives tomorrow.

Since the three holes are sealed and glassed over is leaking really an issue?

I do like the idea of three fewer holes, but then again the screw-through-the-hull thing seems like it would be bulletproof strong.
 

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Discussion Starter · #7 ·
I have Sikaflex 291 to use to seal the machine screws. I guess I didn't mean glass over the heads, I just meant to put some thickened epoxy over them. You're saying that's not necessary?

The existing fitting is on the keel slot, so it's on a sharply curved surfaced. I plan on putting the new thru-hull off to the side of that, on a flat part of the hull.



My plan is to cut off the "horn" and fill the hole with a thickened epoxy plug, then fiberglass over that plug on both sides.

I've never used epoxy or fiberglass before, so this weekend I'm going to play around a bit on some scrap wood to get the feeling for the stuff.
 

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Discussion Starter · #9 ·
if you can get some chopped strand mat and make 3 or 4 little circles to fill the hole you're patching, that would be better. Wet them out thoroughly and stack them neatly in the hole. The foregoing sounds easier than it is.

I've not read Mainesail's article, but I have found that the shrink wrap plastic that is filling boatyard dumpsters everywhere this time of year makes a great backing material for filling a hole. It's got some body to it, and epoxy will not stick. Put a sheet against the hull, back that further with a piece of plywood, and jam it all in place with a stick and a wedge.

Edit to add: Holy heck that's a manly pile of bronze.
Ain't it though? :)

My wife got no end of giggle out of saying "full flow ball valve seacock"

Anyway, you're saying chopped strand mat would be a better plug that sticking in thickened epoxy? How about woven fiberglass, would that work? I already have that.
 

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Discussion Starter · #11 ·
I have that printed out and that's what I'm going for, but the sharp curve of the keel slot confuses the matter slightly. The article says to make a plug and then seal it in with thickened epoxy, but I was thinking I'd just make the plug out of thickened epoxy that way I could mold it to the shape of the curve.

But again, I've never worked with epoxy before so it's highly likely that I don't know what I'm talking about.
 

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Discussion Starter · #18 ·
Decouple the tee from the valve with a length of hose that gets it above static waterline. If it is in a safe location that would be okay but best to come off the valve with hose, then to the tee...
That sounds like good advice, fewer hoses and fittings below the waterline.

It would take some heft away from my manly pile of bronze though :)

I suppose the thing to do would be to have both cockpit drains go right to a 90º pointed towards a T in the middle. That hose could be supported to the floor of the cockpit and they'd meet in a T and there'd only be one hose going down below the waterline. I may have to order more stuff.
 

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Discussion Starter · #30 ·
A few months back I called Groco and asked what material their backing plate was made of. The tech support did not know exactly, but said the material is like a man made plastic plywood. It is not solid and the literature states it can form to non flat surfaces. I am sure you cannot drill and tap the Groco backing plates. The backing plates would only be of use if you plan to through bolt a seacock or Groco adaptor plate. These cannot be used like Maine sail drill and taps the G10 and epoxies to the hull.
I couldn't find any place that sells them. I thought I could save a step and save having to buy a big hole saw if I could buy a pre-shaped backing plate, but although they're in the catalog I couldn't find any website selling them.
 

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Discussion Starter · #35 ·
I have used G10 for a number of different things. It is really a hard material. I use a saber saw with fine teeth to rough cut rounded shapes. Then do final shaping using either a sanding disc on the table saw or sanding attachment on the angle grinder.
Yeah, I have a little sheet of G10 that I'm going to use for the backing plate. That stuff seems crazy durable!

So the jigsaw works for round cuts? I was thinking about that, but I'm afraid I wouldn't be able to cut a very neat circle.

The other option is a hole saw, but that means picking up a moderately expensive hole saw that I'd likely only use once or twice.

(It would also mean clearing away the rubble from the corner of my garage so I could get to my drill press, but that's another issue…)
 

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Discussion Starter · #38 ·
Bi-metal hole saw. Dig out the drill press. G10 is tough stuff. I used a pulsing technique on drill press to fab several backing plates from 1/2" G10.
I guess that's what I'll do. $40 for a 6" bi-metal hole saw at Home Depot. I'll just have to think of something else to use it for to justify the expense. Oversize checkers set?

I'm really not looking forward to tunneling my way back to the drill press... A winter's worth of procrastination is stacked up in front of it.
 
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