Void between the liner and deck on our h27
The layers were fiberglass, balsa, fibergrlass, void (1/4 to 1/8 inch estimated) then liner.I mounted an organizer, winch, and cleat on our deck for single-handing. Drilled 1/4 inch holes all the way through at the right location for the hardware. Then followed by 1 inch holes through the first fiberglass and balsa. Then plugged the 1/4 inch hole in the bottom layer of fiberglass, and fill the hole with epoxy and filler to provide protection to the balsa. When this sets up, drill the final 1/4 inch hole through the epoxy plug. To cover the ends of the bolts, I used a 1 inch thick plank of cherry. I let some of the bolts go through the cherry to hold in securely in place. Then mounted the hardware, fastebibg the bolts that are hiden by the cherry with nuts on fender washers. (all bolts were chosen for lengths to hide behind the cherry in routed slots, or go into holes in the cherry that could be fastened by dead-end nuts. Rounded the corners of the cherry, fastened a teak handle of the right lenght to it. Covered all with polyurethane varnish until it looked right. Mounted the cherry and handle with dead end nuts (used ones with rounded tops, and a phillips slot to hold them while we tightened the hardware from above.Result: Firm, waterproof mounting of single handing deck hardware.Also, a strong and attractive handle running from over the sink to well over the bench on the starboard side. Both the admiral and I are much happier going to the head while under way! Or going below for any reason!That's one approach anyway.DavidLady Lillie