Interesting repair

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DanBerger
Professional
Posts: 275
Joined: May 3rd, 2004, 3:29 pm
Boat Make/Model: SC 15 w/ spin!, SC 19
Location: Norfolk, VA

Interesting repair

Post by DanBerger »

I just picked up a SC 19 that had almost a perfectly round hole on the side near the stern. It looked like someone hit it with a hammer.

I used a hole saw that was about a half inch larger in diameter than the hole and cut out the upper layer of glass/gel and the foam, leaving the inner glass as a support.

I had to cut up a 17 a few years ago--it broke apart at the front beam so it wasn't repairable. I kept the stern, though, to use as a parts bucket. The humanity.

So, I cut a hole out of the bucket at about the same place as the one on the 19--to keep the curve the same. I then used resin to glue it in the hole and then filled the center and edges with filler. I have since fared and rolled on some gel coat and it looks pretty good!

Just thought it was an interesting approach to a problem.
DanBerger
Professional
Posts: 275
Joined: May 3rd, 2004, 3:29 pm
Boat Make/Model: SC 15 w/ spin!, SC 19
Location: Norfolk, VA

Re: Interesting repair

Post by DanBerger »

Hole with larger hole cut out
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IMG_4385.JPG
DanBerger
Professional
Posts: 275
Joined: May 3rd, 2004, 3:29 pm
Boat Make/Model: SC 15 w/ spin!, SC 19
Location: Norfolk, VA

Re: Interesting repair

Post by DanBerger »

Hole cut out of bucket
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IMG_4386.JPG
DanBerger
Professional
Posts: 275
Joined: May 3rd, 2004, 3:29 pm
Boat Make/Model: SC 15 w/ spin!, SC 19
Location: Norfolk, VA

Re: Interesting repair

Post by DanBerger »

new Hole fitted back in old hole
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IMG_4387.JPG
Bill Roberts
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Posts: 515
Joined: November 17th, 2003, 9:13 pm
Location: Stuart, Florida

Re: Interesting repair

Post by Bill Roberts »

Dan,
What makes composite laminate strong is "continuous fibers" spanning long distances.
On your repair on the inner skin there should be continuous fibers connecting the hull strans at the top of the hole to the hull strans at the bottom of the hole and strans connecting the front of the hull hole to the back of the hull hole. In this way the inner skin is restored to original strength. The same for the outer skin, continuous fibers connecting opposite sides of the hole. Now you have close to original strength at and across the hole.
Putting a plug in a hole and gluing it in place with glue/putty not a good fix. Fiberglass has a tensile strength of 150,000 psi. Glue/putty
has a strength of 10,000 psi to 20,000 psi depending on exactly what it is. In composite construction it is the strans of fiber that are strong, not the glue.
DanBerger
Professional
Posts: 275
Joined: May 3rd, 2004, 3:29 pm
Boat Make/Model: SC 15 w/ spin!, SC 19
Location: Norfolk, VA

Re: Interesting repair

Post by DanBerger »

dang, Bill!?

That was a small hole near the stern in a low stress area. I understand that fiberglass is all about the continuous fibers and all that, but in a simple hole repair like this... You don't have to go after it with a hand grenade when a pea shooter will do.
Bill Roberts
Expert
Posts: 515
Joined: November 17th, 2003, 9:13 pm
Location: Stuart, Florida

Re: Interesting repair

Post by Bill Roberts »

Dan, Don't think for a minute that the aft end of the hull is low load, low stress.
How about a jibe in heavy air that breaks rudders off at the waterline or cracks rudderhead castings.
It Happens!
Also the putty/glue ring around the patch/plug you installed has a very different coefficient of expansion
than the foam core hull. In time a print through ring will appear on the surface of the hull where the plug was added.
Since the boat is not be in a boat show on a hot summer day, I think it will be fine.
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