1970 NAUSET Gel Coat Repair

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Nauset1970
Posts: 6
Joined: Sun Jul 23, 2017 8:28 pm

1970 NAUSET Gel Coat Repair

Postby Nauset1970 » Thu Aug 24, 2017 10:07 pm

My 1970 Nauset has had a slow leak--about a pint or a quart--from the transom drain hole when I pull it out after a day's fishing. Some time ago, a storm surge lifted the bow unto the pier and bashed about a hundred chips from the bow gel coat. The apparent leak thru the gel coat has become a concern for rotting out wood structure,and I'd like to fix it. Picture of chips out of bow below.

The underlying fiberglass still seems sound to me--or at least no different from the rest of the hull--per tapping on the chipped sections.

What is the best approach [to repair damage to gel coat]?

Fill each individual hole or sections with lots of chips be ground out and then replaced?

I've been reading the results of the search engine and some items are:

--purchase of a Dremel tool

--polyester resin preferred over epoxy

--get Preval Sprayer for gelcoat and thin with Patch Aid

--use wax paper re-enforced with duct tape for chips more than vertical,
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Paul A
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Joined: Wed Jun 14, 2017 11:50 am

Re: Banged up gelcoat

Postby Paul A » Sat Aug 26, 2017 8:23 am

I have completed two total restorations, 1966 and a 1975, both with all kinds of different fiberglass or gel coat damage.

If only the gel coat is damaged you can sand off the gel coat to expose smooth and solid fiberglass and repaint or re gel coat. If the fiberglass is broken water can get into the foam. In that case sand smooth for good adhesion and fairing of new fiberglass cloth, then gelcoat or paint.

You WILL be able to fair or blend new material into the old undamaged surfaces. I watched videos, used West System (product and guidelines) with Awlgrip primer and topcoat paint. I found the work to be very gratifying and successful.

Expect a lot of prep time and expense for the numerous materials. I sprayed the paint. The paint and varnish alone for my 13-footer was almost $650, including bottom barrier coats and VC-17 bottom paint purchased from Jamestown Distributors.

Nauset1970
Posts: 6
Joined: Sun Jul 23, 2017 8:28 pm

Re: Banged up gelcoat

Postby Nauset1970 » Sat Aug 26, 2017 12:13 pm

Thanks Paul, the under lying fiberglass seems to be undamaged but my main motivation is to stop a leak so apparently there is some damage or possibly tiny cracks letting in a slow leak. Or some other leak.

I forgot to mention that it is a fresh water boat and always on a trailer meaning that the leak only happens when the boat is out on the water, which is probably only 3 or 4 times a year. Still I've had the boat or almost 40 years and would like to prevent any rotting from water inside the hull layers.

It seems to me there are too many small holes in the gelcoat each being about an eight of an inch, to attempt to bevel them with a Dremel tool. So I'm leaning towards using a grinder on the chipped areas and removing the gel coat between the chips in several patches each about 4 by 5 inches. As you suggest if the under layer is damaged it will have to be braced with matt otherwise I'm likely to just coat the patches with polyester resin and then gelcoat the patched areas.

Right now I'm removing the dark brown bottom paint with oven cleaner to expose the bottom gelcoat to attempt to find out if there is or are some other source of the leak.

Thanks again!

Chuck

jimh
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Location: Michigan, Lower Peninsula
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Re: 1970 NAUSET Gel Coat Repair

Postby jimh » Sun Aug 27, 2017 8:54 am


jimh
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Re: 1970 NAUSET Gel Coat Repair

Postby jimh » Sun Aug 27, 2017 9:49 am

Where in relation to the waterline are the damaged areas of the hull gel coat layer at the bow?

Paul A
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Re: 1970 NAUSET Gel Coat Repair

Postby Paul A » Sun Aug 27, 2017 1:34 pm

I repaired a area [of two-square feet with] foam exposed on the bottom of a 13-footer using five layers of 6-ounce fiberglass cloth and epoxy resin. This seemed reasonable but excessive compared to Whaler's guide for structural repairs of "at least two layers" of 2 oz cloth.

Why not make it stronger, other than a few ounces of weight?

Nauset1970
Posts: 6
Joined: Sun Jul 23, 2017 8:28 pm

Re: 1970 NAUSET Gel Coat Repair

Postby Nauset1970 » Sun Aug 27, 2017 4:36 pm

Jim, the chips are below the water line when two or three people are in the bow fishing.

Nauset1970
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Joined: Sun Jul 23, 2017 8:28 pm

Re: 1970 NAUSET Gel Coat Repair

Postby Nauset1970 » Tue Sep 05, 2017 12:27 pm

The work on the gelcoat this Labor Day weekend was to first power sand with a six inch disc sander at 50 grit and then finer sanding with a random orbital sander at 220 grit. Here's some pictures:

Closeup sanding chips.jpg
Close up of sanding of chip damage
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Overview sanding.jpg
Overview of sanded chip damage to gelcoat
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Nauset overview.jpg
Overview of bow of Nauset
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While waiting for the gelcoat to arrive I guess my next step would be to do some wet sanding with a sequence of successively higher grits. Hopefully the gelcoat over the spots will stop the slow leak. Any advice on the project would be appreciated!

jimh
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Re: 1970 NAUSET Gel Coat Repair

Postby jimh » Tue Sep 05, 2017 2:42 pm

I don't think that the damage to the bow, as shown and as described, could be producing a large volume of water ingress into the hull, and that any water that did enter at the bow would not be able to move rapidly to the transom where it can been seen leaking from a poorly sealed through-hull drain.

I think the water that comes out of a poorly sealed through-hull drain probably got into the hull in that area in that same manner, that is, it came in because of the poor seal at the through-hull drain. It did not migrate 15-feet from the bow, through the whole hull structure, to come out at the stern.

The damage at the bow tends to show the laminate under the gel coat is intact and still seated against and sealed to the foam. Yes, exposed laminate may take up some water, but I have my doubts that the water would be able to freely flow through all the laminate or foam and travel to the stern.

After the repair is made, if water still leaks from the drain at the stern after the boat has sat in the water for a while will be an interesting outcome.

Nauset1970
Posts: 6
Joined: Sun Jul 23, 2017 8:28 pm

Re: 1970 NAUSET Gel Coat Repair

Postby Nauset1970 » Tue Sep 05, 2017 4:26 pm

Jim, its not a very large volume, a pint to a quart, but still the water would have to be traveling fast as you point out. Yet still the transom drain is at the lowest point in the boat while in the water. Maybe six to eight hours would be enough to travel back there from the bow?

Don't know what a through-hull drain is, there is a drain through the bottom of the transom but I've sealed around the rolled brass exit on the outside of the transom quite thoroughly with silicone to eliminate leakage around the transom drain as a possibility.

I'm still searching under the bottom of the boat and removing an original, duck hunting camouflage coat of paint with oven cleaner. So far about half of the bottom has been cleaned up without finding anything that looks capable of leaking.

Your opinion is a relief that the damage at the bow seems to be showing structural soundness! So that's a rewarding result of the effort put in at the bow although it doesn't get me any closer to finding the leak.

There's a depth finder mounted into the transom right next to the transom drain, it seems to be sealed but as other possibilities are being eliminated it is starting to become quite suspicious.

More to follow, gelcoat scheduled for Thursday arrival, thanks for your help!

Chuck

Paul A
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Re: 1970 NAUSET Gel Coat Repair

Postby Paul A » Tue Sep 05, 2017 11:28 pm

Jim knows best and I agree with him.. Your pictures show very minimal damage that would leak, through foam, etc. Plugs are probably loose. Seal fabric that is exposed with epoxy. The boats I have repaired have significant visible cracks/damage1

Nauset1970
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Joined: Sun Jul 23, 2017 8:28 pm

Re: 1970 NAUSET Gel Coat Repair

Postby Nauset1970 » Tue Sep 12, 2017 2:07 pm

You all were right the chips in the gelcoat were not the source of the leak. The culprit was my old beer cooler!

I'd even gone to the extent of filling the boat with five inches of water with no leaks. Then it just occurred to me that one of coolers was leaking and sure enough it was that 20 year old cooler (picture below) that holds the beer. That is sure embarrassing but still it is a relief not to worry about water getting into the hull!
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The old beer cooler!
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Paul A
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Re: 1970 NAUSET Gel Coat Repair

Postby Paul A » Sat Sep 16, 2017 6:57 pm

Very funny and a great outcome. That beer sure can cause some unintended consequences. Party on.