Gorrilla glue is a polyurethane glue. It will expand as it cures in the presence of moisture, resulting in a small bubble where the repair is. If you were to sand/shave down the expanded area, you would be left with some what of a foam texture. The expansion makes it great for interior woodworking projects, but there is no U.V. inhibitor to prevent the glue from breaking down. I've worked at yacht manufacturing company for over five years now, and the lack of U.V. protection is the main reason that we use epoxy for everything.
As for the "marine" epoxy, West Systems or System Three are both good brands. The mixing must be exact, and the cure can be very temperature dependant. I've also never really seen marine epoxy available in small quantities; I usually purchase what I need form work or take home the sample packs that vendors send us. It tends to be quite pricey.
I repaired a similar chip in the top sheet of a snowboard a few weeks ago. I used System Three because A) it was already on the workbench B) I use it all the time to make composite canoes, and C) It is used to make custom/homemade skis. Because I left it in the basement to cure, three days later it was still sticky. In the end, I cleaned it up and did it again.
The best bet is to just go down to the local hardware store and pick up a package of LockTite epoxy, make sure it is the clear kind (the other one will cure milky white). The 90 minute version will have a higher strength, and may be more resistant to being knocked off, 5-minute should be just fine though. Tape the area around the repair, and lightly scuff the spot up with some sandpaper, not too fine or the epoxy won't stick to anything (use around120grit). Clean the area with denatured alcohol or rubbing alcohol and allow it to evaporate. The mix up some epoxy and dab it on. This is where I usually leave it, as the epoxy is self-leveling. Wait a day for it to fully cure before use. If you really want it too look smooth, you can shave of any excess with a razor blade and then wet sand with progressively finer sand paper.Locktite 90 minute PoxyPackLocktite 5 minute PoxyPack
I just did a quick check, a quart of West Systems (way
more then you would ever need) is $32 + $15 for the hardener. System Three is around $35 for a 1.5 pint kit. Shipping is usually pricey, and ground only. $3 at Home Depot or Lowes will probably outlast the skis.