Third camp is regular marine
fiberglass wax (along with various prep products) from Meguiar’s or 3M. I used the Meguiar’s Marine
Fiberglass Restoration Kit to bring back a shine on my moderately weathered used
Scamp. I followed with Meguiar’s Flagship Premium Marine Wax for ongoing semi-annual exterior maintenance. It produces a moderate satin sheen on weathered fiberglass.
Zep is currently the most popular alternative to regular fiberglass wax. With multiple (4-6) coats it produces a high gloss sheen even on older units. Fairly inexpensive at big box stores. You’ll need the stripper, too. Anecdotal reports are it lasts longer than fiberglass wax. It can peel if not thoroughly prepped.
Reviews for F11 did not look promising, and it seems to
fall into the category of “miracle” products that promise perfection with no work. Silicone-based according to one review, which can leave unwanted and hard-to-remove residue on fiberglass. Fiberglass was not mentioned among the compatible surfaces. I’m skeptical.