Marking & Cutting Out the Planks

Home
Marking & Cutting Out the Planks
Joining the Plank Lengths
Stitching the Planks Together
Epoxying & Taping
Fitting Gunwales & Seats
Decking & Finishing

AN ON-LINE STITCH & TAPE MANUAL
(Building a New Plywood Design)

(Last up-dated 21/09/09)

 

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 shape and — 8. — clamp them together at each end.
9. Use a couple of workmates to hold the planks vertically and use a plane to trim them down to the line — or 10. — use a belt sander carefully.
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.