Stage
1 - Marking Out the Ply Hull Planks/Panels and Bulkheads/Moulds
The
hull planks/panels are not given full-size (full-size templates are
rarely accurate) and the plans give a 2 page guide on how to draw them
directly down onto the 4'x8' (1220x2440mm) plywood sheets - the process
starts by drawing pencil lines across the sheet at 12" (305mm)
intervals. The dimensions for where the top and bottom of each plank cut
these station lines, is marked from the dimensions given on the drawings
- these points, for each line, are then joined up using a batten
(plastic conduit etc).
For most canoes up
to 16' (4.88m) in length, there will be 4 sets of planks/panels - left,
right (port and starboard), front and back. I usually mark each set down
onto each plywood sheet which means doing this exercise 4 times.
However, some builders mark only 1 sheet of ply and then clamp or
bolt all 4 sheets together and cut through all of the sheets together in
one go - if you do this, make sure that you change the jig-saw blade
frequently and that the base (shoe) of your jig-saw is definitely at
right angles to the blade.
1.
Marking out starts with drawing pencil lines across the sheets of ply
305mm apart for the station Lines (1-7)—measure along the ply and
place pencil marks every 305mm—do this at the top, bottom and middle
of each sheet and then join with a straight edge.
2.
Dimensions for each panel/plank are taken from the lower edge of
the ply sheet- stretch your measuring tape from the lower edge and tick off
the dimensions along each station line.
3.
Draw the curves for the top and bottom of each panel or plank using
a piece of flexible plastic conduit or curtain rail held down by weights
or temporarily nailed in place to lie on each tick mark and use a pencil
to draw the curve.
4.
Curves at the end of the panel/plank—are transferred by using a
flexible rule or carbon paper from the full-size pattern given on the
plans. Mark the bulkhead positions onto the planks.
5.
Cut out each panel/plank using a jig-saw set at slow speed around 1mm
outside the pencil line or —
6.
— use a tenon saw held
at a low angle.
7.
Match all 4 of each plank shapeand
—
8.
— clamp them togetherat
each end.
9.
Use a couple of workmatesto
hold the planks vertically and use a plane to trim them down to the line —
or
10.
— use a belt sandercarefully.
11.
A square is used to make sure that we are planning/trimming the edges
all the same and not taking too much off one side or the other.
12.
Finally mark out the bulkheads carefully and jig-saw them out.