Fiberglassing in hole in thick hull.

[tinkrman69]

Originally Posted by Cheechako

I'm with Jim on this one. I'd plug the hole and grind both sides to put maybe 1/4" + of glass layup on each side and call it a day. Use the plugs you core out of the hole for the new location for the plug!

I second this have done it many times and every one is still afloat

[ramblinrod]

I'm sorry guys, but I strongly disagree with the plug idea. It may be fast and easy, but not best. I believe the goal should be to make the repair stronger than the surrounding material so that the repair is not a weak point. Using a plug makes a weak point.

Rod Brandon
About Sheen Marine

[GrahamHO]

If it is a normal skin fitting hole it should only be around 2" in diameter. I would taper it just enough to get several layers of glass in there.

Personally I would taper each side only about an inch so 2" becomes 3" diameter. Then epoxy glue a 10 mm thick disc of foam in the middle. Then lay up increasingly larger diameter discs of double diagonal glass onto the bit of foam that is in the middle. Do one side then the other Fill the last bit on each side with an epoxy filler mix to enable it to be sanded smooth.

Work the epoxy resin mix into the glass with small 1" or so disposable brushes. Double diagonal glass cloth is very strong and has sufficient bulk to fill the hole. I wouldn't use chopped stand mat as it has little strength being a bit like blotting paper.

I've done repairs in a similar fashion and the hardest part is obtaining a small piece of boatbuilding foam. A friendly boatbuilder might have an off cut.

That's going to be a lot stronger than the hole originally was.

[Don C L]

Originally Posted by ramblinrod

I'm sorry guys, but I strongly disagree with the plug idea. It may be fast and easy, but not best. I believe the goal should be to make the repair stronger than the surrounding material so that the repair is not a weak point. Using a plug makes a weak point.

Rod Brandon
About Sheen Marine

I have to agree with you too. I am sure you could also bang in a rubber or wood plug with a little epoxy and it would probably be fine for years, but I would think ideally the repair will match the strength of the surrounding hull in case of a hit from outside OR inside.

[exMaggieDrum]

I think the operative info here is "thick" hull. A thick hull is inherently very strong and relatively inflexible. So you can get away with a smaller repair area. But I would go with the largest you can get (within reason) to strongly bond all the surrounding glass/resin together. Odds are it wouldn't make a difference but my life seems to be an endless story of regrets for taking shortcuts.

[bobofthenorth]

This is just my opinion but it is based on direct experience with the exact situation. Rather than increasing the size of the damage (the hole) I used a disk on the Dremel tool to cut a keyway in the hull axially around the old thru hull hole. Then I tapered the outside back maybe an inch wide by 1/4 or 1/2 inch around the hole. Then I filled the hole with plugs cut out of fbg cloth. The patch is now mechanically keyed into the hull by virtue of that keyway. I don't see how it is in any way weaker than the original thru hull and in fact I believe it is stronger.

R.J.(Bob) Evans
www.travellingwithgeorge.blogspot.com