Steps in building the SOF kayak

The steps below are a general framework for building a skin on frame kayak using a few hand tools and using many methods similar to those employed for several hundred years. Building a SOF kayak is often not an exercise of building to plan. The measurements are taken from the body of the person for whom the kayak is being built, and there is little use of a ruler in this method.

First, let's define several measurement units:

• fathom: distance from one outspread fingertip to the same finger tip of the other hand when the arms are held as far apart as possible on either side of the body. This distance is normally very close to the individual's height. (note: a fathom for these purposes is different for each individual.)
• fist: width of the clenched fist
• fistmele: width of the clenched fist, but including to the end of an extended thumb
• foot: length of one's foot
• cubit: distance from elbow to end of finger on that arm's hand

(note: a cubit is normally about 3 times the fistmele)

Next, define the measurements of the kayak.

Since the kayak is built from the gunwales (the long strips of wood just above the waterline), one well proven set of measurements is to make the gunwales 3 fathoms long. The width between them at the middle of the boat to be sitting width of the hips plus two fists. The height of the kayak to be one fistmele from the bottom of the keel to the bottom of the gunwale.

The kayak is also defined by several cross deck beams between gunwales: the back brace is placed so that the center of gravity of the paddler will be just aft of the fore/aft center of the boat. The back brace is often placed one foot plus one fist aft of the centerline. The masik (curved upward cross beam forward of the cockpit) is placed so that the individual can sit on the back brace and with straight legs fit their legs under the masik when the gunwales are propped up one fistmele (or a little more) above a flat surface. There are advantages in bringing the masik as far aft as possible to allow a small cockpit opening.

The gunwales are held together at the bow and stern by temporary frames and apart at the middle (and perhaps other stations) by temporary frames. The frames for a West Greenland Kayak are normally held at an angle by the frames. Morris recommends an angle of 17 degrees from the vertical. This angle causes the gunwales to bend into an arc which is expressed as an upturned curve or rocker in the shear line.

The permanent deck braces are fastened to the gunwales with a mortise and tenon joint, or more simply with a couple 1/4 inch wooden dowels. The dowels are trapped in the finished boat by the skin, and can not work their way out. The deck beams are held snug against the gunwale by running a lashing through a vertical hole in the deck beam and through a hole near the bottom edge of the gunwale. The lashing is tightened by multiple half hitchs around the loop formed in this lashing.

Ribs are held in place with 1/8 inch dowels inserted from the outside, but not through the inside surface of the gunwale. The dowel traps the end of the rib in a slot created in the gunwale by either a chisel (hard), drill bit and chisel (medium) or by a router (easier). Ribs can be bent using steam or a heat gun.

Ribs can also be bent by submerging them in boiling water for the appropriate amount of time (or just by pouring boiling water onto them if the piece is in place - or too large to fit in the container of boiling water). Steel pipe, or aluminum house gutters/downspouts can be used to create "pots" tall enough to fit longer pieces of wood. Just fill with water, prop the pot (securely), apply heat to bring the water to a rolling boil, and submerge your wood.

The general plan from that point to the finished kayak is:

- fabricate the remainer of the deck braces and longitudinal beams - build and attach stem pieces fore and aft bracing them from rotation by use of a breast hook. - attach a keel (keelson)) - bend ribs which span the arc from one gunwale to the other without moving the keelson. (it is important to create a shape with these ribs which will have the desired shape in the water. Too flat and boxy and the primary stability will be so severe that it is difficult to roll. Too round, and it will take constant effort to keep the kayak upright as it tries to roll like a log. - Lash everything together - cover with cloth - apply a waterproof treatment to the cloth.

A number of books and articles are written that detail this process and this overview is not sufficient to get you into a usable kayak!

See also:

1. Building Skin-On-Frame Boats, Robert Morris
2. Baidarka The Kayak, George Dyson
3. Building Your Own Sea Kayak (video), Bob Boucher,
4. SK Building A Greenland Kayak, Christopher Cunningham, Sea Kayaker (reprint) Winter 92
5. Building A Greenland Kayak, Mark Starr