Boston Whaler 13 Gunwale Repair

[Limulus]

I got my hands on a battered but now overly waterlogged Classic 13.
Isay not too waterlogged because I can lift bow, stern, and sides off the trailer. At 68 the stern was not easy, but I've checked out some hulls I can't even shift.. i think most of the of the needed repairs are pretty straight forward (though I reserve the right to backtrack on that).

What I would like some experienced thoughts on is how to repair the gunwales... Obviously I cannot replicate the original construction.
The inner and outer skins are so thin putting the same amount of glass over 4 lb foam won't do. What i intend is to fill the area of removed foam with slightly less foam to allow me to lay a layer of CSM, 2 layers of 1708 and a layer of 6 oz woven to prep for fairing and gel coating.
Small areas I'll fill with Dura-Glas and cabosil.
1) Will that be strong enough for the gunwales?

2) Given that a 12:1 bevel is meaningless in this case, how far should my sanding and overlap go?

3) I was thinking that placing some. Slightly scrunched up wetted out fiberglass along the length of the void before pouring the foam might add some stiffness (not rigidity) to make up for the lack of unibonding...
(I recently came across this loose fiberglass infill on a pulpit off a big cruiser . It made it ridgid beyond belief.)

Thank you, if you made it through this post.View attachment 207774

 

[kapnD]

You might do well to try and bag the whole gunnel and apply vacuum over a long period of time to remove the inevitable water trapped within.
There’s so little structure remaining there, I’d be tempted to cut the remaining glass off and build a new gunnel of Coosa board.

 

[fallguy]

That is crying for some foam inlays. After bonding in the foam; remove all the local gelcoat and taper it and build back with csm and polyester smallest pieces first. Use clear poly plastic and masking tape to make patterns and rip; don’t cut the csm to fit. About 3 layers or so depending upon the glass thickness.

I recommend using a 12mm thick foam. See if you can get a few offcuts or local supply and buy one sheet.

 

[Limulus]

Upon further study, the recommendations from Whaler-centric sources, the recommendations are ironically, exactly what I was taught to do for other old fiberglass boat repair... Try to replace using similar materials in similar quantities... So 2 or 4 lb (4 for gunwales) and then a layer of csm, and 2 or 3 layers of 6-10 oz cloth with a layer of csm on top for sanding. Suggested not to use plywood or coosa, (and except to replace wood accessory inserts). Hardened 1708 is Stronger and more importantly stiffer and even with feathering, will change the way the hull flexes, and be prone to stress cracking of the old glass where it meets the new. I was tempted to armor the boot with a full layer of 1708, but after. having ground off the old layers of paint and gel coat on the outer hull, i was pleasantly surprised to find it was in good shape, including two patches which were done with layers of (non epoxied) light cloth. Having ground a little farther into the foam, it's bright white and dry as the day it was poured. (A primary reason for buying this old beast, was that the hull is very light)
Thanks for the responses, they made sense to me too.