Sarum Skin-boat How-to

Not the only way, but the way we've done it that works. An important word: what you find here is an IMCOMPLETE record of the process, created for a student who was unable to complete his boat at school. As time goes on, I may fill in steps, but this is by no means a full set of directions. When it comes out soon, I recommend the book Building Skin-on-Frame, Double-Paddle Canoes by Hilary Russell,of Sheffield, MA.

Order of Operations

  • Creating the Stem-Knee assembly
  • Attaching Knee to Keelson
  • Fill four spaces in gunwale for thwart attachment
  • Sand gunwales and breasthooks
  • Attach thwarts
  • Fit, drill gunwale rub rails
  • Assemble floorboards
  • Shape nose and tail for brass rub rails
  • Coat all wooden parts with oil or varnish: frame, rubs and floorboards
  • Skin the boat
  • Shrink the skin
  • Skin coating
  • Attach all rubrails, wooden and metal
  • Last odds and ends

Notes on related subjects


Knee - Keelson Assemby and Shaping

Keelson glued to Knee
Keelson faired into knee to create curve of the boat end


Putting the Stems and Knees Together.

Stem and knee glued and clamped together on a flat surface.

The curve at the bow and stern of the boat are glued together from two pieces to avoid weaker, short-grain sections when making this sharp turn.  It could also be done with a naturally crooked piece of wood, and we have done this once, but it requires seasoning the found piece for a season or so, plus the actual harvesting of the wood, so for us its easier to piece them together.  This could also be laminated to create the curve.


Odds and Endings

In no particular order:

Grab loops.  A couple short lengths of  7 or 8 mm perlon (climbers cord) make nice grab or hanging loops at each end.  Make a loop, tie the two free ends together with an overhand knot, and shove the loop through the hole in the breast hook from inside, so the knot catches under the breast hook.

Seat cushion:  in the past I've used some of the leftover canvas to cover the chunk of seat foam.  This year I tried using some of the fabric dye to color the cushions - not a good idea, as it turned out;  the dye ran when Matt and Peter tested their boat, so I had to remove the covers and wash them in hot water to resolve that problem.  Hence the pinkish faded color in this photo.

Maker's mark:  The little bronze tag that says Sarum Boats.  Easy.  Drop into the shallow hole and pin with two tiny brass brads.

Paddle note:  While a skilled paddler, can pilot this boat with a single bladed canoe paddle, using the 'J-stroke', the boat is a joy to paddle with an extra long double bladed kayak paddle.  There are some links to manufacturers on the Sarumboat blog.  A little research on the Internet will also yield sources of plans for building your own, if you wanted to try that.  This paddle will seem unusually long, compared to what you might find at the average EMS.  Mine is 260 cm (102 inches).  We made some here at school which are about 8' 4"  (by the way, rubber drip rings are a good idea for your paddle shaft - they prevent some of the water picked up by the blades from running into the boat.)


Reattaching the wooden rub rails aver the staples is easy - just screw them back in.  I recommend doing it by hand (tedious, but a good wrist workout) or using a drill with adjustable torque settings, set so that the clutch slips before you can crank the screw too hard.

The bronze stem bands are a bit trickier.  Start with the boat upright, and place the bronze 1/2 round on the breast hook and in contact with the stem.  Drill pilot holes for the first two screws.  The screw pack has enough longer screws for two at each end of the boat. Use the short ones everywhere else. Once the band is attached with the first two screws, turn the boat bottom side up and proceed.

Screw pack.

Start by anchoring the rubstrip on the breasthook.

Last screw on the underside of the boat.

The bronze 'rub' or stem band tends to bend more easily and sharply where the holes are drilled, so place the screws one at a time: drilling, screwing, aligning and bending as you go.  Run a narrow (1/4") bead of silicone down the keel stringer where the stem band will lay, to seal the screw holes and the staple seam (though this may be redundant, given the properties of the polyurethane).  When the band is screwed down, wipe and excess squeeze-out of silicone off with a rag.  Vinegar works well to clean up smears on the skin.


Coating the Skin

The material we have been using for the past two years to coat the skin of the boats is a two-part polyurethane that we purchase from the Skinboat Store, in Anacortes, Wa. This is mixed one part A to two parts B and stirred THOROUGHLY. It needs to be well mixed to set properly, and believe me, to be left with a sticky, uncured mess on your boat skin would be a disaster of the first magnitude. On kayaks, the best way to apply this is with a scraper/squeegee, but with the additional stringers and multiple lashings making small bumps on our skins, the best way is with a disposable foam brush. Three coats can be put on a few hours apart, though in our school setting we have done coats on successive days, and it has worked just fine.

In the photo below, an acid dye (also from the Skinboat Store) called Russet (they carry 8-9 colors) has been used to color the canvas at the same time we shrink it. If you use just the polyurethane with no dye, the color will be a pale, yellowish transparent film, almost like skin of some sort.  To shrink the skin with no dye, just put the boat out in the hot sun, and hose it down with cold water.  Then let it dry.  If using the dye, but the dye in a spray bottle, and with a rag in one hand and the sprayer in the other spray evenly and then wipe to prevent runs. Once the entire boat is done, let it dry in the sun.

A perfectly good alternative is water based polyurethane from the hardware store. It dries fast; you can put on a coat every few hours, and build up to 5 coats quickly. For an opaque, color coat, mix ¼- ⅓ artists’ acrylic gesso and some acrylic paint of your choosing with the polyurethane for the first couple coats. Brush it as evenly as possible to avoid brush marks. Finish with 3 more coats of poly.