Need advice on filling in a 1-1/4" thru hull hole

[Glaspar_Fan]

I have a 27 foot Searay with a poorly placed bait tank supply thru hull fitting. The previous owner must have placed it where he did because it was easy to get to without any thought to it being in the way or what would be on the other side. I can accommodate the inconvenience of having the plumbing sticking up in the engine compartment right where you need to stand to service the batteries, etc. But on the outside, the thru hull strainer/inlet sets square on a trailer bunk. The one time I had the boat out, there was a bad list to port while on a plane with the tabs up. Walking side to side didn't have much effect. No sign of listing at rest, so the boat seems balanced OK. The more I think about it, the more I think the area around that thru hull is going concave due to the pressure of the trailer bunk and taking a set that way.

So any way, I'd like to remove the thru hull and fill the hole. Any suggestions? I've been thinking of making a mahogany plug and epoxying it in. Then fairing with some glass outside and reinforcing inside with a board and more glass. So what's the right way to do this? I've worked with West System epoxy before (made my own car fenders and nose) but never tried patching a hull.

Thanks,

John

 

[ondarvr]

Re: Need advice on filling in a 1-1/4" thru hull hole

The listing to one side probably has nothing to do with the fitting, but it's easy to get rid of.

Since you can get to it from the inside just take the fitting out, grind the inside, put some tape on the outside and glass over the hole (from the inside). When that's hard you can do a cosmetic repair on the outside. Resin choice isn't going to be that critical, use what you're comfortable with. There is a little more to than that, but that's the general process. Forget a wood plug, it will just create problems.

 

[Canada_Jim]

Re: Need advice on filling in a 1-1/4" thru hull hole

Okay, not an expert, but I did work in a fibreglass plant for a few years. And here is what I believe to be true; Epoxy resin and polyester/styrine resins are not compatable with each other, your boat is almost positively made of the latter. A strucural repair such as what you are suggesting must be done correctly, or will become a potentially hazardous condition. This would consist of grinding out the repair location from the exterior, in a conical shape begining at the say a 2" hole location, outward and upward to the hull exterior gelcoat surface to what would probably be a 10" diameter repair area minimum. Then after taping up the hole on the inside, the glassing would begin, starting by cuting up the right weight of mat 5/8" or so larger than the 2" hole, and progressively getting larger to the extent of the ground area. The mat must be imursed in correctly catylized resin and worked into each piece with a paint brush, or the likes. Each piece should be placed and rolled with a fibreglass roller tool to remove all air. This resin typically catylizes fast so you can expect to get a couple of layers on per batch. Between batches the new layers must be roughed up with the grinder to insure good bonding. Building up as described allows the new glass to bond to the old in vertically stacked layers not in line with one another (am I being clear enough on this?). When the repair is up to existing elevations, it can be sanded to slighty below gelcoat elevation, then sprayed with catylized sanding gelcoat, and shaped using layers much like bondo and primer for autobody.
This type of repair is not out of the question for a home enthuisiast, but you would have to be a well equipped one. I would want a good compresser with small angle grinder, orbital sander, air-board sander, and polisher. Also a good fitting respirator filter mask, tyvek coveralls, gloves, and some fibreglassing hand tools. I would also expect to incure some angst from my neighbors due to the fumes...............

Hope this helps............Jim