Will this work for fiberglassing a thru-hull?

[Ben4195]

Hi All!

I've started wading into the process of updating my new-to-me 1975 C22, and one of the major projects I'm hoping to complete before April 1 is to replace the original gate valve thru-hull with a proper ball valve (I think that's what it's called anyway). I had seen a thread on here where Minnesail (I think) fiberglassed over his original gate valve thru-hull and cut a new hole for the ball valve thru-hull a few inches to starboard of the original, so that's what I was planning to do too.

I have almost no experience with fiberglassing, but it doesn't look too complicated. I don't have a West Marine or other type store locally so I have to order the materials. Is this the product I need to order to patch the old gate valve thru-hull hole?

105-K Fiberglass Boat Repair Kit | West Marine

Check out our 105-K Fiberglass Boat Repair Kit and more from West Marine!

www.westmarine.com

Thanks so much for any help!

 

[dmax]

Fiberglassing a hole in the bottom of your boat might not be the best first project you want to do. There's lots of info out there on the proper way to do it, watch this video for an idea:

Why not use the existing hole, it's a lot easier even if you have to enlarge it.

 

[Ben4195]

Dmax, I will if I can. I don't know how easily I'll be able to get the old gate valve off while still being able to preserve a surface suitable to mount a new ball valve. I assume that's why Minnesail didn't use the existing hole. you can see his installation in the thread below.

New to me 1975 Catalina 22: questions

Hi folks, I just checked off a bucket list item, getting myself an old Catalina 22. It appears to be in rough shape, almost everything on it needs replaced, but it seems to be solid enough. However, i have some questions. 1. how do you know when the keel is cranked all the way down? There...

forums.sailboatowners.com

 

[dmax]

You should be able to get that old through-hull out - use a reciprocating saw with a metal blade (or a Dremel tool if space is too tight) and cut it off. On mine, I cut the nut in half and chiseled it off. Just cut metal and not the fiberglass and you should be ok. Usually takes 5-10 minutes. If you haven't already, read MaineSail's advice on through hulls before starting:

Replacing Thru-Hulls and Seacocks - Marine How To

Tip: If you would like a higher resolution or larger photo simply click on the picture and it will get bigger. A Poor Idea The picture on the left is what not to do if starting from scratch and installing new seacocks.

marinehowto.com

 

[Richard19068]

You can also use a grinder to grind off the mushroom head on the outside of the hull.

 

[Ben4195]

Good thought, Richard. If you look at my picture though, you'll see the gate valve thru-hull is in the swing keel recess. I don't think I'd be able to attack this from the outside for that reason, as well as because the swing keel itself is likely in the way.

 

[AaronD]

@Ben4195: You definitely want to replace the gate valve with a ball valve; some people have found that screwing a ball valve onto the original pipe works great; others found that the original pipe embedded in the hull isn't well bonded Mine was probably fine, but I don't know how I could have told the difference without reefing on the threaded pipe, thus destroying the threads... Which was fine, I was already planning the replacement. See my notes and pictures if they're helpful.

I sealed over the original through hull by epoxying a stack of fiberglass (G10) circles into the hole, followed by a few layers of fiberglass tape top and bottom. I haven't ever painted the bottom, but it doesn't see any UV there anyway (and I don't care if my keel trunk looks pretty ).

And yes, West System epoxy is a great product for this. There are other good brands too, but I'm happy to support West.