filling small holes hull BELOW waterline

phatmanmike

Captain
Joined
Oct 24, 2003
Messages
3,869
i have a 16 foot center console fishing boat , that has(had) 2 livewells in the back, one on each side. each livewell had 2 through-hulls, one at bottom and one at top of the livewells, going straight out the side of the boat. i removed the live wells and the through hulls and now have these 4 holes in my boat, and they are just throught the fiberglass part, no wood, so the material is only bout 1/4" thick. <br /><br />what would be a good way to patch these so that i can float again. im not worried about cosmetics, just flaotability.<br /><br />thanks
 

mellowyellow

Vice Admiral
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Jun 8, 2002
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5,327
Re: filling small holes hull BELOW waterline

do you have inside access mike? if yes, I'd tape over inside and use 3M 5200. exactly how big r we talking?
 

18rabbit

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Nov 14, 2003
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3,202
Re: filling small holes hull BELOW waterline

You could put the thru-hulls back in and cap them. Other than that, MarineTex is an off-the-shelf, ready-to-use to epoxy product with fillers that will work. It's made specifically for your application. Personally, I prefer it over the 3M 5200 for filling a hole in the hull, tho 5200 would be ok for small holes above the water line. But even better, I would use two-part epoxy … I would prep the edges of the hole in the glass, then put a backing surface over one side of the hole, mix some epoxy, mix in enough fibers to get a mayonnaise consistence, add silica or cab-o-sil to get a peanut-butter consistence, then filler ‘er up.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
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28,418
Re: filling small holes hull BELOW waterline

Mike, the holes from the thru-hull fittings are likely 3/4" or larger. I would make a glass cloth patch for the inside of the hull, if you can get to it. As 18R says, Marinetex is excellent, however asking it to bridge holes this big at 1/4" in thickness is a bit much. I would sand the inside of the hull, and create a patch of fiberglass mat to fit in the holes. I would lay a 3"X3" piece of cloth over the hole from the inside and saturate the cloth and mat with epoxy. After it hardens use either polyesther or marine tex to "putty" any imperfections and sand smooth.
 

TomMcKinney

Cadet
Joined
May 25, 2003
Messages
11
Re: filling small holes hull BELOW waterline

If you have access to both sides of the repair area I would suggest the following for 3/4 inch holes--<br /><br />1. Cover the outside of the hole with a piece of wax paper that's 2 inches by 2 inches. Secure it to hull by taping over with duct tape.<br /><br />2. Fill the hole with thickend epoxy. Marine tex putty can be used here since it alows you to make a small amout of thicked putty.<br /><br />3. When putty has cured, wipe off amine blush on the "inside" part of the repair with acetone. According to what I have read, almost all epoxy will have some blush, even if you can't see it.<br /><br />4. Clean an area around the repair of 6x6 inches with toulene to enusre there is no wax from manufacturing the boat. I have read that this is advised reagdless of the age of the boat as some wax may still be present.<br /><br />5. Sand the 6x6 area with 60 or 80 grit and clean again. Cut 2 pieces of 6 ounce or 9 ounce wovem cloth, one 3x3 one 6 x6. Can also use tape here in various sizes to get similar area of coverage (for example if you had 16 inches of 4 inch tape, cut out a 4 inch piece and two 6 inch pieces, use the 4x4 for the 3x3 and use the two 6x4s butted up for an 8x6 <br /><br />6. wet out the 6x6 area in the boat. Place the cloth on another piece of wax paper and wet out both pieces thooroguhly. Place the 3x3 piece over the hole, then place the 6X6 on top. When the epoxy has set up abit, add another coat to fill the weave. You can then cover with wax paper to minimize blush and promote a smoth surface.<br /><br />7. When its all cured, remove the wax paper from the outer hull. If the reapir is not fair to the hull, clean and and as above and fill with a faring putty. Use talc mixed with epoxy, for an inepnesive faring putty. Yes that means you can use baby powder.<br /><br />8. You will have to paint the reapir as epoxy has little UV resistance. For such a small repair, I would simply use white outdoor spray paint (assuming a white hull) and sand out with 400 or 600 wet/dry.<br /><br />If you need to make a cosmetic rapir on the inside part with the fabric/cloth, then you can fair that out with the putty as well.<br /><br />Gel Coat and polyester filler should be avoided as they have problems sticking to the epoxy. Epoxy will adgere to a polyester boat much better than a new polyester reapir will.
 
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