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Fitting Planks on a Clinker Vessel (small boats)


A clinker dinghy is made up of a number of planks each side; the number of planks is determined by the size and shape of the vessel. A clinker plank is overlaid the plank below for a lap (clinker is also known as lapstrake construction, as strake is another name for a plank and lap describing the joint between each plank).

Each plank is joined through the lap, and it tends to make a very strong and light structure which is ideal for boat construction. The joint usually is not caulked especially on the small dinghy. So ‘watertightness’ relies on a good lap between planks and it being well fastened.

There are different ways to finish each end of a plank in clinker hull construction; for example the full thickness of the plank could run into the stem or transom. However, usually the plank’s thickness is reduced so that the planks become flush at the stem or transom. This is known as a half lap (half the thickness is removed from the bottom edge of the top plank and the top edge of the bottom one, hence half lap). This type of joint is also known as the geralds.

This technique in constructing a hull has been successfully used for quite large vessels (Viking long boats for example), however, it tends to be limited to smaller vessels today. It makes light, strong and pretty dinghies.

The skill demonstrated will focus on preparing the existing fitted plank for the next one, sorting the stem and the transom. Then preparing the next plank, fitting and fixing it into position. All this will happen on a small sailing dinghy (14’ clinker Fowey River sailing dinghy).


The process is demonstrated in the accompanying video clips with a step-by-step guide. The conversation with the boat builder, in this case Marcus Lewis, is unscripted and covers the technique from his experience.

Part 1

  • Preparing the stem for the next plank

  • Mark the bevel on the plank

  • Planing the bevel on the plank

Part 2

  • Planing the bevel on the plank continued

  • Trimming the transom end of the last plank fitted to the dinghy

  • Dry fit the plank to check shape

  • Planing the half lap or ‘geralds’

Part 3

  • Planing the half lap or ‘geralds’ for the aft end of the plank

  • Check the fit of the plank

  • Fitting the plank

Part 4

  • Fixing the plank in position

  • Mark the position of the nails

  • Riveting the planks

  • Finishing and fixing the plank at the transom

Part 5

  • Finishing and fixing the plank at the transom continues…

  • Riveting the last part of the plank
Kies Taal...

Benodigd Gereedschap

  • Chisels
  • Plank template
  • Planking stock off cut
  • Smoothing plane
  • Panel Saw
  • Rove driver
  • Light Hammer (ball-peen hammer)
  • Side cutting pliers or snips
  • Clamps
  • Wood ‘U’ clamp
  • Ruler
  • Rebate plane adapted (Marcus used old wooden ones)
  • Work bench
  • Square
  • Fein Multimaster type of saw or similar
  • Drill bits (suitable sizes)
  • Dollie
  • Cordless battery powered drill
  • Personal Protective Equipment (PPE)
  • Pencil

Benodigde Materialen

  • Larch planking stock
  • Off cuts of some planking stock
  • Suitable glue
  • Square shanked copper boat nails (1¾” 12 gauge)
  • Copper roves