Use self tapping or sheet metal screws. Wood screws have tapered threads and shaft. If you drill a hole big enough for the shaft in FRP, the hole is too big for the threads. Woodscrews are for WOOD with it's unique elastic abilities.
Self tapping screws should be more than adequate for mounting gear
hammocks. Some boats even had the hull
joints fastened with sheet metal screws. I also understand Hunter
used the same fasteners to attach fittings. Definitely not reccomended but an idea of how strong, though not for long, sheet metal screws are.