I very much doubt that you will find any canvas vendor who has canvas in-stock that was specifically designed to fit a 1998 150 DAUNTLESS boat from Boston Whaler. This is mostly due to the boat being 25-years-old. Canvas vendors do not and could not in 2023 maintain a stock of products that were specific to a particular 25-year-old 15-foot boat from a certain manufacturer.
You real choices are as follows:
- buy canvas that is simply generic boat canvas but of a suitable size that you can adapt it to your boat and successfully install it;
- buy canvas from the legacy OEM provider of Boston Whaler boat canvas, Wm. J. Mills & Co., which may have patterns for canvas for your particular Boston Whaler boat; or
- engage a local boat canvas artisan to take measurements and create canvas to fit your particular boat.
Option 1 will be the least expensive, by far. Option 2 may not even be available; check with Mills to determine their status. Option 3 will require you finding a suitable artisan to do the work.
When comparing boat canvas prices, there are three primary influences on the costs: the material used in the canvas, and the material used in the frames, and the artisan doing the work.
For many decades the preferred fabric for boat canvas has been the Glen Raven Mills product called SUNBRELLA. This material has proven itself as a premium product, but it accordingly comes with a premium price. There are other material available, but I don't see SUNBRELLA as being threatened by any of them.
The construction of the supporting frame for a Bimini top generally takes two forms: aluminum tubing used with plastic fittings, or stainless steel tubing used with chrome-plated metal fittings. Stainless steel and cast metals will have much more durability than aluminum and plastic, and will accordingly cost more.
Producing boat canvas is generally done in two methods with completely different scaling. Generic canvas is mass produced in larger shops by a cadre of workers using standardized patterns, and custom-fitted canvas is made by a single artisan or a very small shop and fitted to a specific boat. Again, custom-fitted made-to-order canvas will cost much more than generic off-the-shelf canvas.
A good method to find a skilled canvas artisan that is local to you is to visit some large marinas in your area. Walk the marina docks and look at boats with excellent canvas. Most every canvas artisan will sew on a label in a prominent location of their boat canvas to identify themselves as the maker.
As in many products related to boats, the cost for top-quality work using top-quality materials from a top-quality artisan will be expensive. Also, the really best artisans often have substantial backlogs of work, so expect to have to wait as long as a year to get a job done with them.
For a 15-foot open skiff boat, I think you will be very nicely served with quality generic canvas, carefully chosen to be adaptable in size to your boat, and if you are handy, installed by you. The recommendation given above Carver is a good choice.