Detachment of Gunwales Attached With Adhesives

A conversation among Whalers
User avatar
Phil T
Posts: 2602
Joined: Thu Oct 22, 2015 6:08 pm
Location: Was Maine. Temporarily Kentucky

Detachment of Gunwales Attached With Adhesives

Postby Phil T » Wed Aug 31, 2022 9:25 am

Regarding the failure of the adhesive joint between the hull and the molded gunwale cap on some post-1990 Boston Whaler boats:

I have consulted with four owners who had the gunwale caps on post-classic designed-after-1990 models severely damaged. The incidents I refer to include:
  • corrosion of the support bracket led to adhesive failure in two incidents
  • installation of a pot puller without necessary support.
  • improper use of a rod holder to secure the boat to a pier led to gunwale cap separation.
  • loose gunwale cap, cause undetermined by new second hand owner.

In the cases above, I advised the owners on the options, techniques, and materials to repair the boat and redesign the installation of rod holders.

I would be hesitant to install a large rod holder to the gunwales without some significant modifications.

In addition to an aluminum backing plate underneath the gunwale, I would also install additional L-brackets forward and aft of the rod holder to provide more support. Mechanical fastening may be more desirable over high strength adhesives.

[Moderator's note: salvaged and separated from a fanciful discussion on whether or not one person could land a 300-lbs tuna on a 19-foot boat in the open ocean without damage to the gunwales.]
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
Posts: 11670
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Detachment of Gunwales Attached With Adhesives

Postby jimh » Wed Aug 31, 2022 9:33 am

Phil--thanks for sharing your knowledge on the detachment of gunwales from the hull on post-1990 boats.

My 1990 REVENGE has molded gunwales and they are presumably attached with an adhesive. I have never given the strength of their attachment to the hull a second thought. On the REVENGE, however, the cockpit gunwales are part of the whole-hull superstructure cap, so the adhesive bond is on the complete hull length, bow to stern on each side. I cannot image that the superstructure cap could be pulled off the hull in the course of normal boating activities. I would expect that the collective strength of the adhesive bond over that long distance would impart enormous resistance to becoming detached.

On the gunwales on my boat the following are mounted:
  • side railing bases
  • swim ladder attachment fittings
  • rod holders
  • stern quarter cleats
I have never seen any evidence of a looseness in the gunwales; they seem completely secure and part of the hull structure. My boat is 32-years-old, and it seems as rigid and solid as ever.