A plank-built boat goes together in a fixed order: set up the keel and stems (the backbone), plank the hull from the bottom up, fit ribs and thwarts, make the seams watertight, and finish the wood. Strip planking, with narrow strips edge-fastened over temporary moulds, is the lightest variant, but it normally relies on waterproof glue; hide glue is reversed by warm water and casein glue is only water-resistant, so without a waterproof glue the strips must be nailed and the seams caulked, as in a carvel hull.
Part of Canoe & Rowing Boat Construction
A plank boat is a wooden hull built from boards fastened to a backbone and ribs, the step up in capacity and seaworthiness from a coracle or dugout.
The Order Of Work Is Fixed By What Supports What
Every plank boat starts with the backbone: the keel, and the stems at bow and stern, or a transom if the stern is square. Everything attaches to that spine. Next come the planks, built up from the garboard (the lowest plank, beside the keel) to the gunwale. Ribs and thwarts brace the shell; seams are sealed; the wood is protected. Skipping ahead is not possible, because each stage supplies the geometry for the next.
A well-built rowing boat serves a community for 20 to 30 years of daily use, according to the carrier, but only if each stage was done well. The common failure is the earliest: a backbone out of line, which spoils every plank that follows.
What You Need
- Timber: keel and stems of the hardest, straightest wood available; planks of straight-grained, seasoned softwood or hardwood (see Wood Seasoning)
- Tools: drawknife, plane, saw, auger and brace, clamps (see Hand Tool Making)
- Fasteners: copper nails and roves for riveting, or nails and screws
- Sealing materials: oakum, pitch, tar (see Boat Sealing)
- A building space that is level, sheltered and large enough to walk around a 5 m hull
Method: The Build Sequence
Step 1: Backbone. Shape the keel, stems and transom, scarf where needed, and join them (see Keel, Stems & Backbone).
Step 2: Planking. Plank clinker (shell first) or carvel (frame first); see Planking Methods.
Step 3: Ribs. In clinker, steam-bend and fit them after the shell; in carvel, they are erected first (see Ribs & Frames).
Step 4: Gunwale, thwarts and knees. Add the top rail and cross-seats, which also brace the hull.
Step 5: Seal and finish. Caulk or check laps, soak the hull, and apply protection (see Surface Treatment).
Step 6: Float test. Launch the empty boat at a mooring and wait a day before loading; the planks swell and leaks reduce.
Worked Example: How Many Planks?
Assume the hull’s side from keel to gunwale measures 0.9 m (an assumed shape; measure your own) and each clinker plank exposes 12 cm after a 3 cm lap (the carrier gives a 2-3 cm overlap), so planks of 15 cm width. Planks per side: 0.9 ÷ 0.12 = 7.5, so 8. For both sides 16 planks, each as long as the boat unless you join shorter boards with scarfs. If the boat is carvel, the same girth with 12 cm planks gives the same count. This arithmetic matters because the lumber budget, the seam length to seal (63 m of seam for 14 laps of 4.5 m) and the fastener count all follow from it.
Common Mistakes
- Starting to plank before the backbone is checked — measure both diagonals and hang a plumb line.
- Using unseasoned planks — they shrink, open seams and crack (see Moisture Content).
- Treating strip planking as glue-only — the glues in this wiki are not waterproof (see Hide Glue and Casein Glue), so nail the strips and caulk the seams.
Safety
A hull on trestles can fall
A 4-5 m hull can weigh many tens of kilograms. Block it so that it cannot roll, wear eye protection when driving nails, and keep fingers away from the clinching side of rivets.
What’s Next
- Learn next: Keel, Stems & Backbone — the first stage in detail
- Combine with: Oars & Rowing Technique — the propulsion once the hull floats