|Why chance it? I have a friend who had to make a fast trip to the Travellift because his drill bit was longer than his hull was thick. Putting in a screw cost him $100.00 - not fun. I'm not crazy about creating a path for water to enter the laminate, either, even if your screw hole does stop short of the lake.
For wires, I'd use a string of those 3M "Command" cable clips with the removable adhesive strips to fasten the clips to the underside of the sole. These worked for me in the galley lockers; if the adhesive doesn't work in the bilge, I'd just fix them with fast-acting epoxy.
C&C 27 Mk IV