Assess Condition of 11-foot Hull from Photographs

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Chris_D
Posts: 2
Joined: Sun Oct 13, 2024 4:39 pm

Assess Condition of 11-foot Hull from Photographs

Postby Chris_D » Sun Oct 13, 2024 4:57 pm

I recently bought a 1981 11-foot Boston Whaler in France. After a first test run, the boat was back on its trailer, and I noticed a piece of laminated fiberglass was hanging from the stern. I had not hit anything and didn't drag the boat on rocks. Maybe the hull rubbed a bit on the trailer rollers.

I do not understand what I am seeing. It looks like a layer of [resin-]impregnated fiberglass cloth was added on top of the original hull.

Q1: could a layer of the original hull have peeled off?

I cannot identify what is below the peeled-off layer. Here is a link to some photographs:

https://postimg.cc/gallery/662TSfr

Any opinion or advice would be much appreciated,

I read many articles on the forum, but I did not find anything similar to my situation.

--Christophe

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Assess Condition of Hull from Photographs

Postby jimh » Mon Oct 14, 2024 7:54 am

The four photographs you provide lack good lighting, and to see exactly what has occurred from those images is difficult. Below in Figure 1 is the a portion from one of your images.

transom11-footer.jpg
Fig. 1. The transom of an 11-footer.
transom11-footer.jpg (53.9 KiB) Viewed 11817 times


The general construction of a Boston Whaler hull would typically NOT have cloth mat material immediately at the surface of the hull.

A normal Boston Whaler Unibond hull will have the following layers:
  • an off-white or very light tan color gel coat resin layer that is about 1 to 2-mm thick;
  • a layer of polyester laminating resin with randomly oriented small strands of fiberglass material, often with a slight green hue, perhaps 5-mm or more in thickness;
  • if in the transom area where an engine would be mounted to the hull, a layer of reinforcing wood, encapsulated in polyester laminating resin, perhaps 15-mm thick; and
  • a tan color high-density foam.
All these layers would be very strongly bonded to each other.

On the basis of what can be seen in Figure 1, my inference is that at some point a layer of woven cloth fiberglass was added to the hull and very poorly bonded to the original hull material.

The normal appearance of the transom of a Boston Whaler Unibond hull can be seen in the article linked below:

The Green Line Transom Joint
https://continuouswave.com/forum/viewtopic.php?t=6209

Chris_D
Posts: 2
Joined: Sun Oct 13, 2024 4:39 pm

Re: Assess Condition of 11-foot Hull from Photographs

Postby Chris_D » Mon Oct 14, 2024 8:43 am

Thanks for your quick reply, and, yes, that’s what I thought when I saw this woven material not supposed to be part of the construction.

Now the question is why the previous owner added this extra layer of fiber, to fix or to prevent damages. In any case it is not quality work.

Q2: could the dark layer underneath the now removed?

Q3: could all [the original layers be] gone?

I guess I ll have to remove all this extra layer--if I can remove it.

Image Image Image

jimh
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Location: Michigan, Lower Peninsula
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Re: Assess Condition of 11-foot Hull from Photographs

Postby jimh » Mon Oct 14, 2024 9:10 am

For advice on making repairs to the Unibond hull of a Boston Whaler boat, please read the repair instructions published by Boston Whaler, which are preserved at

Boston Whaler Hull Repair Instructions
https://continuouswave.com/whaler/refer ... tions.html

To determine exactly what repairs or re-working has previously been done to the hull and what reasons caused that to be done is, of course, impossible. But, as noted, that the work was not done properly is quite clear from the delamination of the new work.