removing glass covering keel

[Amherst Island]

We are the lucky and proud owners of the last of the Lake Ontario Tumlare fleet built in 1938. Kryssa is a beauty, in terrific shape and has sailed every one of her 70 years. For several years we have wanted to remove the multi-patched fibreglass and epoxy coating put on below the waterline sometime in the 1960's. Maybe this is the year we shall find the time and energy, and so we are looking for any suggestions on how best to go about this.

[JimConlin]

If the sheathing was done in the sixties, there's a good chance that it was done with polyester resin rather than epoxy.
Epoxy softens dramatically under a heat gun and can easily be peeled. If it's polyester, some of it might not be well adhered and can be peeled off with a large chisel and the rest will need to be sanded.

[George Ray]

Best to start with air supplied hood and full suit and a plastic tent draped down to contain the dust. Your neighbors and boatyard regulations and common sense these days will likely dictate that.

If there are no fastenings (unlikely) and the base is polyester it will all just peel off fairly easily in sections/sheets once you start it by lifting up the edge with a chisel and tearing along score/tear lines that you make with a razor knife or shallow set skill saw. Peeling up easy does not mean is was bad it is just the nature of polyester resin.
If glass layer is fastened to the planks you might best grind through the paint to the translucent glass/resin layer and by wetting it down with literally anything clear (water, varnish, oil, resin) you should be able to see the heads of the fastenings buried in the glass. You can then grind just to the wood taking off the head of the fastening and leaving the shank in the plank and then peel the glass off. It the fastenings are ferrous steel you might not like this but if they are bronze or CRS then 'no problem'. Trying to pull every fastening shank from the plank is likely to be more trouble than it is worth and also will leave the planks with a thousand little holes that you will have to fill (UGH!). If the base resin is epoxy it may boil down to grinding the glass layer off... double UGH!!!.

There are tools that are used to strip off layers of glass. Sometimes fiberglass boats with severe osmotic blister problems will get the bottom 'peeled' (layer removed) and then reglassed. The folks that do such work are really your best bet unless (a) the tests show it will be a simple peel off job or (b) your have lots of time, money and a double extra dose of gumption.