I have 2 17 foot supers, a folding model about 30 years old that is still in decent shape and a rigid that I picked up last year that needs a new hull. I do custom canvas and upholstery for a living here in Michigan, and am fairly familiar with all the materials ( fabrics) available. I do not know of a direct replacement for what folbot used on their hulls, that material seems to be a heavy weight pure vinyl. However their are a few modern fabrics that I think will work well. I was planning to use 35 oz Coverlight H Hypalon on mine, at least for the hull . The manufacturer lists the following properties water resistant, seams gluable to make them air/water tight, high abrasion resistance, puncture and tear resistant, UV resistant, Unfortunately this only comes in black and it is pricey, over $30.00 /yd (60 inches wide) wholesale, probably more retail. However it is ideal for glueing, in fact it can be used to make over the road truck tarps using only glue for the seams. It is available in a 17 oz, probably suitable for the deck, for about$20 yd, and that comes in yellow, green red, and white.
there are some other fabrics which may be suitable as well, including shelterite 22 oz , weblon structurall and herculite 18 ozat around $10/yd,
Until I do my boat these are just guesses, I have never covered a fabric hull before, but have used the Weblon and Herculite before for other applications, they are tough and come in colors. I will be glad to share my impression of the hypalon when I do my own, but knowing my workload it may be mid to late summer before I have time to work on anything of my own.
canvasguy of michigan