The QuickLap Canoe
Lapstrake boats are to many people the
prettiest boats on the water. The shadow lines formed by their
overlapping planks highlight the contours of the hull, leading
the eye to follow it's shape. They have a reputation, however, of
being difficult for an amateur to build. A builder must first
accurately cut a series of molds, spaced at regular intervals on
a strongback, to define the hull's shape. Wooden strips, or
ribbands, are then fastened to the molds to outline the shapes of
the planks in a process called lining off. All of the pieces made
to this point help to define the hull's shape, but do not become
part of the finished boat. If multiple boats are going to be
built to the same design, the time spent constructing the
building jig can be economically divided among all the boats; if
only one is being built, jig construction becomes a substantial
part of the building time.
When I first started exploring the possibilities of
computer cutting boat parts I really wanted to try building
lapstrake boats. Only after a lot of experimenting did it occur
to me that a lapstrake hull could be built like a stitch and glue
hull, with one half of the lap added to each plank's
width. This "slipped" stitch-and-glue method required a
flexible "rivet" so that the planks could bend to a
natural shape. Plastic cable ties inserted through paired holes
in the plank edges, with cable ties slipped over their ends, were
just the thing. Using this method, the shape of the planks define
the hull's final shape, not molds or frames. After the hull is
riveted together, the overlaps are filled with an epoxy mixture,
locking the shape and creating a lengthwise "stringer"
at each lap.
Designing for the " QuickLap" method was
much more difficult than I had imagined. Since this method allows
the hull to take on it's own natural shape, the shape that was
drawn on the computer screen was not always the shape of the
finished hull. After many hours at the computer and several prototypes I had
a design for an 11' double-paddle canoe that I was happy with, loosely based on
Henry Rushton's Wee Lassie. This 13'6" QuickLap canoe evolved from that first canoe.