At the conclusion of a complex build, the energy, ingenuity, and budget for an elegant floorboard installation is sometimes lacking. In a traditional dinghy it is not unusual, for example, to see floorboards fastened directly to the hull’s steam-bent ribs.
A very solid structure is achieved when thwarts are anchored to the centerboard trunk, and to the gunwales with hanging knees. The boats don’t have floor timbers, which provide a flat surface for floorboards in some boats, because they reduce valuable internal depth and stability.
While it may be common practice with plank-on-frame construction of this sort to fasten floorboards to the ribs, the floorboards are then a nuisance to remove, and repeated removal of the screws will damage the oak ribs. I’ve seen this death-by-floorboards phenomena in a few small boats.
A better solution is required to avoid treading all over the cedar hull, and to promote maintenance and longevity. My answer is a set of four easily removable panels conforming to the shape of the hull interior. I make the panels using the same materials that go into the hull construction—3/8″ clear vertical-grain, freshly cut western red cedar, and bending oak identical to the hull ribs.
Starting with the first course alongside the centerline and trunk, the individual floorboards are shaped to mimic the run of the first three hull strakes. I use thin plywood for pattern stock, and a combination of scribing, spiling, and eye work to arrive at the shapes. For example, the lower edge of the first floorboard course can be scribed directly alongside the center floorboard.
The top edge of the first course might be spiled, or scribed with an offset block, to roughly follow the garboard/broad. One begins with a general sense of layout and proportion, the eye to follow.
While fastening to the panel ribs, the courses are separated by temporary 3/4″ spacers. This is wide floorboard spacing. The gap is keyed to heel rests which I have designed, featuring a tongue projecting below the floorboard to brace against a rib. The 3/4″-wide tongue provides more bearing than a 1/2″ tongue. The floorboard spacing can be whatever suits an individual builder.
After all three floorboard courses are fastened to their respective panel ribs, the completed panel is removed from the hull, and the outboard rib ends are trimmed flush. A slight under-bevel and easing here of the rib end will later help ensure the panel easily slips in and out. With 3/8″-thick cedar and 3/8″-thick ribs, I use 5/8″ screws. I prefer full-thread stainless-steel sheet metal screws for their firm bite.
One element favoring this arrangement is that the hulls of this line of boats are clench-nailed through laps and ribs, so there are no roves obstructing the lay of the floorboards. If your boat has the planks riveted at the frames, you can put the floorboards in place, then tap them against the frames to get the peened rivet heads to dent the floorboards. Use a small gouge to create hollows in the backsides of the floorboards to accommodate the roves. The panels need to slide outboard a wee bit as you remove them. You would need to accommodate for this movement when making these divots on the underside of the floorboards mostly, I think, for those roves closest to centerline.
The panel system prevents damage to the boat’s ribs and planking and offers quick, easy access to practically all of the interior hull. Removing and installing the floorboard panels involves no fastenings, no tools, no guessing, no springing into place, and no errant holes. Maintenance of the boat is encouraged rather than discouraged, and the large area covered by the floorboards is a plus for small boats that are often sailed while sitting on the floorboards.
Eric Hvalsoe grew up in a boating family near Seattle, Washington, and got glimpses of the San Juan and Gulf islands, and northern British Columbia waters, at an early age. He later revisited some of these destinations, including the Broughtons, in sea kayaks and, most recently, traditional sail-and-oar craft. As Hvalsoe Design, Eric has been designing, building, repairing, restoring, and maintaining wooden boats since 1980. His home and shop are located in Shoreline, Washington. Eric teaches traditional boatbuilding and lofting skills at Seattle’s Center for Wooden Boats, where the collection includes some of his designs: the Hvalsoe 13, 15, and 16. His family of sail-and-oar designs has expanded to include the Hvalsoe 18. For a while longer yet, Eric hopes to continue exploring the Salish Sea in non-motorized craft.
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