View Full Version : Plugging Holes in Hull

01-14-2008, 04:03 AM
"Hello, awsome site here!

One of many questions to come- I am replacing a kicker bracket on the back of my '78 Olympic fibergalss constuction, and the new bracket has a different bolt pattern. What is the best way to go about sealing/plugging the previous holes? Thank you in advance, Aaron"

01-14-2008, 09:31 AM

Marine-tex putty comes to mind....."

01-14-2008, 11:29 AM
"This is an approved method of repairing machined holes in below the water line portions of the boat. It is important because there is a plywood core in the transom and if water gets in it there will be rotted wood and the entire transom will need replacing soner or later. This is from the website westsystems.com. http://www.westsystem.com/ewmag/21/practical.html ("")

West marine epoxies are the best when working below tha waterline. I know from many years of large sailboat experience.

Example A 1" diameter hole drilled near the hull bottom through a structural laminated fiberglass bulkhead with a " plywood core. Bilge water should not be allowed to flow through the hole.

Since the repair is to a structural component and needs to be watertight, the consequences of failure are higher than the previous examples. While it is likely that simply filling this hole will provide enough strength, overlaying the plug with fiberglass will provide more strength and better sealing. What is needed here is to bond in a wood plug that is a bit thinner than the plywood core so that once the epoxy cures you can laminate over it and maintain the original bulkhead thickness.

Fill the hole with a wood plug using the method described in the previous example and then bevel the laminate at 12:1 ratio on the edges where the new laminate will overlap onto the original. Apply enough fiberglass to match the thickness of the original laminate. Apply paint or gelcoat over the finished surface"

01-14-2008, 07:35 PM
"seems like overkill for his job, Robert. but good advice overall. I recommend dowels with a little epoxy to seal. marine tex or life caulk to finish."

01-14-2008, 09:49 PM
Thanks for the advice guys! I picked up my new Garelick kicker mount today. Instead of drilling new holes I was thinking about fabbing a new frame to use the existing holes to then mount the Garelick bracket to... What do you think? (it would be stainless ofcourse)

01-15-2008, 12:29 AM
"I think it sounds like a lot of work. I also think it's your boat, and you should do the job that your pride demands. is there a real city of wetside, or are you just describing the basic weather?"

01-15-2008, 05:44 AM
"Im somewhat of a fabricator and I have everything other than the steel to do it so... we'll see?

No actual town of "wetside", I am a transplant here and have always been close to the sun- and Western Wa IS wet whereas Ea Wa is very dry!"

01-15-2008, 10:04 AM
I looked up the bracket you are planning to install. It looks like an above the water line type. If so then the hole plugging is not as critical. If it were me I would plug the holes with a dowel covered with epoxy or (polyter resin if above the waterline) about a 1/2" shorter than the transom. Push it in to center it in the transom then fill the outside of the holes with epoxy and a filler mix. you can use fiberglass pieces as the filler. Wet them and push them into the hole. When they set then sand off the excess. I expect the holes are 1/4' or 3/8". This should make a good watertight seal and then make the new holes you need.

Be sure to use a adhesive/sealants (3M's 5200 is excellent)on the new bolts. You sure do not want water in the plywood core of the transom.

01-15-2008, 12:47 PM
Take a MIG welder and....Whoops! That's one of those glass boats. Forgot. Mine is aluminum.