Mounting Bimini Top Frame to Hull

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
jaszber
Posts: 1
Joined: Fri Dec 06, 2024 7:07 pm

Mounting Bimini Top Frame to Hull

Postby jaszber » Mon Jan 20, 2025 2:00 pm

On my 1998 SUPER SPORT LIMITED, I want to remount the Bimini Top from Wm. J. Mills & Co.

After filling the previous holes with epoxy and sanding:

Q1: do I use stainless steel self-tapping screws with 3M-4200FC Adhesive/Sealant as per https://continuouswave.com/maintenance-logs/bimini/

Q2, or, do I follow the Mills recommendation, and use flat head machine screws and 10#10-32 Thread Well Nuts?

Cf: http://cf.millscanvas.com/cfml/documents/52-5750-00%20Hardware%20&%20install.pdf

Available from:
http://cf.millscanvas.com/cfml/Product_Detail.CFM?ProductID=194

jimh
Posts: 13290
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Mounting Bimini Top Frame to Hull

Postby jimh » Tue Jan 21, 2025 10:18 am

The article you link to (which I wrote in 1999) shows a method of installing a different Bimini top from a different manufacturer onto a different boat.

The linked PDF document you refer to shows the method of installation recommended by Boston Whaler for the Mills the Bimini top you have which is to be mounted on the particular Boston Whaler boat you have.

To save readers the time and trouble pf downloading the Boston Whaler document you refer to, I include an illustration that is an excerpt from the drawing:

MillsWellNutDwg.jpg
Fig. 1. Detail of mounting hinge base from Wm. J. Mills & Co, instruction sheet.
MillsWellNutDwg.jpg (61.77 KiB) Viewed 11517 times


The situation illustrated is similar in both instances: there is NO embedded wood reinforcement under the gel coat and laminate layer at the location of the hinge plates for the Bimini top frame.

Regarding which method to use, it is really your choice. I would, however, suggest if you use the metal expansion nut then also employ some sealant to avoid allowing seawater to get into that metal part and producing rust or oxidation. The Boston Whaler drawing does not give a recommendation for the manufacturer of the "well nut", but I would expect that a typical hardware store well net would not be impervious to rust or oxidation, so ingress of water should be prevented.

ASIDE: I no longer own the 1976 SUPER SPORT 15 that is the boat mentioned in my 1999 article about mounting the TaylorMade Bimini top to its gunwales, but I am still in contact the the present owner. As far as I know, the unusual offset angle plastic hinge plates are still well secured in place on the sloping gunwale 25-years after they were installed in 1999.