Fiberglass crack by winch

Sep 24, 2018
2,917
O'Day 25 Chicago
This crack seems to be really deep. I did not take a close look but there's no noticeable damage on the underside. I assume this is just a gelcoat crack?
Photo Oct 16 2024, 5 43 33 PM.jpg
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
21,900
CAL 35 Cruiser #21 moored EVERETT WA
Winches need adequate backing plates. Not all installs are completed with adequate backing.:facepalm:

Winches are sometimes used by owners to do tasks they were not designed to do. :eek: This often shows the weaknesses of the install.

I would remove the winch. Identify the structure under the winch and repair any weaknesses discovered. Clean and patch the surface blemish's and then reinstall the winch with a strong backing plate.

One can speculate on what occurred to cause the issue. :banghead: But the cause is not relevant to your needs for a strong winch on the boat.

You are not the first new owner to buy a boat only to discover hidden opportunities for improvement of the now "their boat".

On the positive, you have a nice sized self tailing winch that will serve you well in the 2025 season.
 

dLj

.
Mar 23, 2017
3,696
Belliure 41 Back in the Chesapeake
Is that winch on the O'Day 25? What's the year of production?

Lots of early boats used quite thick gel coat that would later exhibit cracks like what you are seeing. It is quite likely it is nothing more than a gel coat crack. But it is definitely worth a bit of investigation.

dj
 
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Likes: FastOlson
Sep 24, 2018
2,917
O'Day 25 Chicago
This is on my new to me 94 Catalina 30. The O'Day coamings are built like a tank. It was tested one stormy day and the winch mounting bolts failed with zero visible marks in the fiberglass. I gained a ton of respect for fiberglass that day

I'm leaning more towards this being a deep gelcoat crack since there's no cracks on the underside. A large wood backing plate isn't a bad idea for the future. Still seeking out a few more opinions on this crack
 

dLj

.
Mar 23, 2017
3,696
Belliure 41 Back in the Chesapeake
This is on my new to me 94 Catalina 30. The O'Day coamings are built like a tank. It was tested one stormy day and the winch mounting bolts failed with zero visible marks in the fiberglass. I gained a ton of respect for fiberglass that day

I'm leaning more towards this being a deep gelcoat crack since there's no cracks on the underside. A large wood backing plate isn't a bad idea for the future. Still seeking out a few more opinions on this crack
I prefer stainless steel backing plates - but wood would work. I've also used starboard as backing plates - never used wood...

I was watching a video - don't recall the website, they do all kinds of testing of boats - and they were taking a fiberglass boat and ramming it into a rock jetty to see how well the fiberglass hull held up to serious impacts. Surprisingly well it turns out...

dj
 
Sep 24, 2018
2,917
O'Day 25 Chicago
There's plenty of material options for backing plates. I figured wood or starboard might help absorb some impact. I have some marine ply scraps so the only things that I might have to buy are longer bolts
 
May 17, 2004
5,368
Beneteau Oceanis 37 Havre de Grace
Is the area solid glass or cored there? From the looks of the crack and your statement that the underside is fine my guess is there’s rotten or at least elongated holes through a core that’s allowed the top layer to shear. If there’s no core the cracks would concern me less.

If there’s underside is still fine I don’t think a backing plate will make much difference. The point of a backing plate is to spread load so the underside doesn’t collapse under compression, but if that hasn’t happened yet I’d say the original design was good enough.
 
Sep 24, 2018
2,917
O'Day 25 Chicago
Is the area solid glass or cored there? From the looks of the crack and your statement that the underside is fine my guess is there’s rotten or at least elongated holes through a core that’s allowed the top layer to shear. If there’s no core the cracks would concern me less.

If there’s underside is still fine I don’t think a backing plate will make much difference. The point of a backing plate is to spread load so the underside doesn’t collapse under compression, but if that hasn’t happened yet I’d say the original design was good enough.
I'm not sure if it's cored or not. I cut into the coaming of an old C27 once and it had a LOT of core. Very well built. I think your analysis of this is very good, especially regarding backing plates and compression
 
Apr 8, 2010
2,018
Ericson Yachts Olson 34 28400 Portland OR
I'm leaning more towards this being a deep gelcoat crack since there's no cracks on the underside. A large wood backing plate isn't a bad idea for the future. Still seeking out a few more opinions on this crack
I agree with others here that it's likely a thicker section of gel coat, and it can show a crack due to shrinkage as it ages. For a backing plate I would go with a quarter (or 3/8) inch of G10, set in epoxy mush. I had no such cracks but did that for all 8 of our stanchions and all 6 winches. Smaller G10 plates under the clutch stoppers also. Proactive beats "reactive" for stuff like this. (IMHO) And when these stressed-in-use parts are off the deck, over-bore, epoxy the holes, and rebore. Yup, we did that for 100% of our deck fittings.
 
Apr 1, 2004
156
Catalina 34 Herring Bay Chesapeake, MD
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