I have a 17' Fiberform runabout. I get water in the liner, not the hull (bilge) when running at cruising speed.
The boat has two plugs, one for the hull and one for the liner (floor/deck). The bottom plug for the hull is always dry. I have looked at all the posible ways water could get into the liner and can't figure it out. The well for the outboard V-4 is all molded fiberglass.