Keel grounded : gelcoat crack advice - SailNet Community
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post #1 of 10 Old 05-13-2012 Thread Starter
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Keel grounded : gelcoat crack advice

I would like to share some toughs reading some slight (?) cracking I found on my boat (pictures attached), after I grounded it in a local river.

It's a 32footer, fin-keel. The keel is attached using studs, bolts and washers.

The boat was grounded on an underwater sand "hill", at a speed of about 1.5knots. The keel dig in no more than 5 inches of sand/mud and did not manage to stop the boat.

I can see some light cracks in the gelcoat around the washers of two studs. There is also a small cracks near the inside frame, at the center studs.

There's no damage on the aft studs and no delamination or detachment detachment of the inside mold.

I hope that this is only gelcoat crack and that the GRP is still intact (as it should be)...

Any hints?

thank you.
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post #2 of 10 Old 05-13-2012
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Re: Keel grounded : gelcoat crack advice

Welcome to SailNet! What make boat? Looks fairly new! You could seal the gel coat by removing the nut and washer off one at a time. (so you don't loose the keel to shoe stub joint. You could also use that as an opportunity to get or have made LARGE washers or plates to distribute the load when you re-install the nuts. This is just suggestions from reading what others have done.. My boat doesn't have keel bolts
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post #3 of 10 Old 05-13-2012 Thread Starter
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Re: Keel grounded : gelcoat crack advice

I'm new around here (still need to go trough presentation).

This is a 2004 sun odyssey 32i.

Plates would be nice, but I don't feel like doing it in the water (more than one nut removal per time is required). Perhaps I can get a machine shop to build some custom big washers out of 316 steel?

Let's hope the gelcoat is the only damage. Any grp expert around?
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post #4 of 10 Old 05-13-2012
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Re: Keel grounded : gelcoat crack advice

This doesn't look typical of actual damage from a grounding.. and a non-stopping grounding in sand at such a low speed should not cause any real issues.

If you had a serious impact causing damage in those areas you'd see much more dramatic cracking, and separation of the ribs and stringers from the hull itself. I think you got off with a warning.

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post #5 of 10 Old 05-14-2012
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Re: Keel grounded : gelcoat crack advice

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Originally Posted by deniseO30 View Post
Welcome to SailNet! What make boat? Looks fairly new! You could seal the gel coat by removing the nut and washer off one at a time. (so you don't loose the keel to shoe stub joint. You could also use that as an opportunity to get or have made LARGE washers or plates to distribute the load when you re-install the nuts. This is just suggestions from reading what others have done.. My boat doesn't have keel bolts
Denise is right - I'd make up the largest backing plates that would fit in the relevant spaces. I have never understood why manufacturers hang keels on simple washers but winches and other deck hardware have big, honking backing plates. The traveller mounts on my boat have backing plates 10X the size of those keel fasteners.

I've attached a pic of what I made up for the 10,000 Lb. keel on my 43'. The pieces of S/S channel are 2" X 4" X 24" - there are 5 of them, eaching spanning a pair of bolts.
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62. New keel hardware #2.jpg  
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Re: Keel grounded : gelcoat crack advice

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Plates would be nice, but I don't feel like doing it in the water (more than one nut removal per time is required). Perhaps I can get a machine shop to build some custom big washers out of 316 steel?
2 at a time in the water should be no problem - the load safety margin on keel bolts is huge - many multiples of the max. loading to account for dynamic loads. When I had my 10K Lb. keel off, the boatyard forklifted it around it with a strap attached with only 2 of the 10 bolts - no problems.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
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post #7 of 10 Old 05-15-2012 Thread Starter
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Re: Keel grounded : gelcoat crack advice

I feel much relieved now. Thank you. I was very surprised to find the cracks after such a small incident. Apparently recent rain has modified the local river bed and some dredging is necessary.

Bigger plates will be, then. And I guess a keel drop at the end of the season to check if water made it between the keep and the hull.
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Re: Keel grounded : gelcoat crack advice

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I feel much relieved now. Thank you. I was very surprised to find the cracks after such a small incident. Apparently recent rain has modified the local river bed and some dredging is necessary.

Bigger plates will be, then. And I guess a keel drop at the end of the season to check if water made it between the keep and the hull.
Don't assume you have to drop the keel to check - when you lift the boat, if there is no cracking around the joint, it is still intact. If you have a "smile" then you should check further. Dropping a keel is a pretty big job.

Between now & then, keep a close eye on your bilge to see if there is any "new" water ingress. Keep it wiped completely dry each time you are on it. If it stays the same as it has been, that's more good news.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
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Re: Keel grounded : gelcoat crack advice

Yes, the bilge is dry and all seems good. Will use your advice. Thank you.
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Re: Keel grounded : gelcoat crack advice

Monitored bilge closely

Monitor cracks closely

Dive and check hull-keel joint

sail and have fun

Haul boat at end of season and hopefully just retorque bolts and add a bit of sealant at joint.


FYI - we design ( and I'd guess everyone does) keel bolts with a factor of safety of 5 and usually jump up to next size. Meaning, on the Schock Harbor 30 any 1 of the 8 bolts and washers can support the e tire keel load even in a pounding sea

Last edited by WDS123; 06-25-2012 at 12:22 AM.
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