While we are waiting for a DSII owner to chime in, let's take this systematically.
The first thing that would worry me is the source of the crack. If you don't counteract the stresses that were leading to the crack in the first place, then there's a good chance that even a solid repair might be damaged again soon.
Otherwise, repairing fiberglass with expoxy is not hard. Searching the sites for West System or System Three will give you links for manuals, such as the
Epoxy Book. (Searching this forum will dig up some disucssion of working with epoxy as well). Reading up on that will give you some necessary background if you have never done epoxy/fiberglass work before.
What you don't do is just pour epoxy into a crack. A proper repair starts by widening the crack, so the expoxy can actually get in there. After that, you could use epoxy mixed with glass fibers to fill the crack (short shavings of mat or cloth would do in a pinch). That would get the crack watertight.
After that, you'd want to put an extra layer or two of glass over the crack as a patch, to support the area. If that would make a bump on the hull, you would first need to grind away a bit of the existing material, so the repair becomes flush. In that case, adding some reinforcement on the inside (backside of crack) would also be useful.
Perhaps this will give you a start towards a repair.