It is usually recommended to put a few layers of fiberglass in the repair, but when I redid the bottom of my H16 hull a few years ago, I used only thickened epoxy. However, mine wasn't worn all that deeply into the original fiberglass. I rough sanded the hull bottoms and then put an unthickened layer of epoxy down. Then followed with a layer or two of thickened epoxy to build up the bottom to it's original shape. After sanding, I followed up with a couple coats of paint (spray can) that matched the boat. Epoxy should have paint over it for UV protection.
I'm not saying this is the best way to repair a boat, but it worked pretty good in my situation. Like you, I rarely landed my boat on a beach, so future wear wasn't a big concern of mine.

Jack
Fort Loramie, Ohio