Repairing Damage to Keel of Unibond Hull

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
ChesapeakeBill
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Joined: Thu Dec 13, 2018 8:53 am

Repairing Damage to Keel of Unibond Hull

Postby ChesapeakeBill » Thu Jan 03, 2019 3:27 pm

I just purchased a 1987 Montauk 17. The previous owner did a lot of restoration but didn't finish the hull. I have no idea what he did. It looks messy, and I want to do this boat right.

[Some damaged area near the keel of the MONTAUK 17] doesn't appear to have any breach into the foam--a good thing. The previous owner started something. He also did the same thing on a couple of other spots on the side of the hull.

My plan is to paint the bottom as it will be on a mooring in Maine.

What should I do (or not do) to [repair the damage] and get the hull looking good.

[Leave the thread, go to these URLs to see images]
https://photos.app.goo.gl/4AMnBewDVbXXjQHw7
https://photos.app.goo.gl/JYTfLm4UDTuTnXNz7
https://photos.app.goo.gl/Z82tcfnDfNeJ9AAv5

jimh
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Location: Michigan, Lower Peninsula
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Re: Repairing Damage to Keel of Unibond Hull

Postby jimh » Thu Jan 03, 2019 3:56 pm

For a good overview of methods to make proper repairs, read these three articles:

The Epoxy Cure
Repairing Hull Damage the Whaler Way
INSTRUCTIONS -- HULL PATCH KITS

Assess the repairs already made. If the repairs are not faired into the surface, use sandpaper to make them fair with the surface. If the repairs are suspect in their integrity, grind them out and start over. It will be extremely difficult to make any assessment of the repairs already made from photographic images.

jimh
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Re: Repairing Damage to Keel of Unibond Hull

Postby jimh » Thu Jan 03, 2019 4:00 pm

Since you just bought the boat, you must know the previous owner, at least well enough to buy the boat from him. Inquire with the previous owner about what sort of resin and materials he used to make the repairs.

ChesapeakeBill
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Joined: Thu Dec 13, 2018 8:53 am

Re: Repairing Damage to Keel of Unibond Hull

Postby ChesapeakeBill » Thu Jan 03, 2019 8:24 pm

Thanks for the info and guidance so far. The previous owner is recently deceased, his estate sold it to me as-is. He did a lot of restoration before he became ill

What do you think he could have used for his patch job?

I wish he would have done the keel before he re-powered, added a new console, leaning post, re-wired it, and added all the electronics. This is the only "problem" I could find. Not sure where to start, Close assessment and some sanding is a good start, thanks.

As I said the bottom is to be painted so was I hoping the patchwork would be below the waterline, we'll find out when we float her.

jimh
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Re: Repairing Damage to Keel of Unibond Hull

Postby jimh » Thu Jan 03, 2019 10:40 pm

I would use this method to assess the repairs:

--assuming the boat has not been in the water in a long time, look for any indication of water having dripped out of the hull at any repair area;

--check the strength of the repairs by apply pressure with your hand against the hull; there should be no sign of any flexing;

--use a small plastic-head hammer to tap on the hull, listening to the report of the tap. The sound should be uniform in all areas. If you hear something that sounds different in one area, it could be a sign of a hull void.

If the fellow did nice work on the other repairs and revision, he probably was doing good work on the repairs. In the pictures the hull repairs look like they are not completed.

There are two schools of thought about what resin to use to make small repairs: polyester resin or epoxy resin. I prefer epoxy; many prefer polyester. There is much prior discussion about what resin to use.

jimh
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Re: Repairing Damage to Keel of Unibond Hull

Postby jimh » Sat Jan 05, 2019 10:42 am

ChesapeakeBill wrote:...plan is to paint the bottom as it will be on a mooring in Maine.


If you will be keeping the Boston Whaler hull in saltwater on a mooring, be sure to follow the advice from Boston Whaler in the owner's guide regarding proper preparation of the hull. If you don't have the owner's guide, I have reproduced one in HTML. See

http://continuouswave.com/whaler/refere ... tml#bottom