Planking

Putting planks on Seapod has been such hard work that I have not had time to write it up. I’m up to plank 5 or 6 now and things are getting a little easier - so here are a few pictures to be going on with.

The inside of each plank is ‘carved’ out to fit the outside faces of the timbers. This is done using a plane with a curved sole and blade. I made mine by adapting a wooden block pane. The process is called ‘backing out’.

Once backed out the scarfs (joins in the plank) look curved - if the backout is even the curve is even. A home made template (we call such things ‘FIDs’ - I don’t know why) is used to check that the curvature is even and correct for the timbers at that point along the plank. You can see the plank curvature FID to the right of the plane.

As at last Friday this is what the planking looked like.

Elsewhere there has been lots of progress - some boats have finished planking/hull construction and the Gig has had her molds taken out. The lines, to my eyes, are wonderful. She will never look this beautiful once she is filled up with thwarts and knees!

I’ll write more about the travails and tribulations and pleasures of planking a carvel boat once I manage to catch breath and reflect…

In the meantime, here is my recipe for planking happiness - a working process outline - ignoring what happens when things go wrong (please excuse the jargon).

For each master plank (port side)

1. Spile lower edge (nearest to keel) of plank from upper edge of previous plank
2. Record required bevels for lower edge of plank
3. Record backout profiles for plank and infer maximum plank thickness
4. Select planking stock from rack and thickness stock to maximum required plank thickness
5. Work out scarf angles and position for planking stock, mark out, cut and glue scarf (glue dries overnight)
6. Transfer lower plank edge points and timber lines from spiling batten to scarfed planking stock
7. Adjust lower edge plank edge points using recorded bevels
8. Fair bevel adjusted lower edge of plank using a batten
9. Mark out points on upper edge (furthest from keel) of plank using calculated planking widths recorded from ‘lining off’ process (plus subsequent adjustments)
10. Fair in upper edge of plank using a batten
11. Cut out planking stock using jigsaw
12. Rough plane within 1mm of marked lower edge of plank and (approx) 5mm from upper edge of plank
13. Offer up plank for sanity check on fit
14. Plane square to marked lower edge of plank
15. Mark and plane bevel on lower edge of plank
16. Back out the inner face of the plank to match recorded backout profile.
17. Get the lower edge and hood ends of the plank to fit (adjust lower edge, hood ends and apron/stem to fit upper edge of previous plank and rabbets – may require steaming of the hood ends)
18. Plane upper edge of plank square to the faired line.
19. Rough sand the inner face of the plank with 80 grit sandpaper
20. Drill and countersink for screws in all timbers and hood ends and fit screws

For each slave plank (starboard side)

1. Scarf planking stock as for master plank
2. Place master plank (on or after stage 19) on planking stock, draw outline and transfer orientation markings to planking stock
3. Cut out planking stock using jigsaw
4. Rough plane within 1mm of marked lower edge of plank and (approx) 5mm from upper edge of plank
5. Offer up plank for sanity check on fit
6. Plane square to marked lower edge of plank
7. Mark and plane bevel on lower edge of plank
8. Back out the inner face of the plank to match recorded backout profile.
9. Get the lower edge and hood ends of the plank to fit (adjust lower edge, hood ends and apron/stem to fit upper edge of previous plank and rabbets – may require steaming of the hood ends)
10. Plane upper edge of plank square to the faired line.
11. Rough sand the inner face of the plank with 80 grit sandpaper
12. Drill and countersink for screws in all timbers and hood ends and fit screws
    

After planking is complete

1. Mark outgauge (for caulking) on all planks
2. Remove planks
3. Plane outgauge & hood end bevels
4. Apply final adjustments to fair rabbet & hood ends
5. Sand inside of planks with 180 grit sandpaper
6. Coat inside faces, edges and screw holes of planks with 2 coats of WRA 200
7. Re-fit planks, bedding the hood ends with Sikaflex 291

At a later stage

1. Fill screw holes
2. Fair hull
3. Prime and caulk seams