The Siskiwit Bay SOF is a multi-chined version of the original Siskiwit Bay cedar strip boat.
Note: The sheerline and design features sweeping curves that might challenge first-time Yost-style builders.
The basic process of a wooden framed Yost-style SOF is to cut out the six wooden frames, shape them to accept stringers.
Bryan Hansel is a freelance writer, award-winning photographer and an American Canoe Association L4 Open Water Coastal Kayaking Instructor. Could I use the stations(forms) of the SOF version in order to better controll the construction of the S&G version for the Siskiwit bay MC ? The LV has a rounded hull shape that’s designed for cedar strips, and it has a slightly different shape with more rocker.
You don’t need offsets, because you can just take the drawings to an office supply store and have them print full-sized. Nestings are the individual station drawings laid out on a ARCH-D-sized electronic paper, so you can print the individual stations off without wasting much paper. Hi Bryan, I’ve been researching different SOF designs for some time now and I have to say that your Siskiwit is so perfect for me. I epoxied the scarfs and actually dowelled the stringers at the stems with epoxy, but lashed the rest. Description: The Siskiwit Bay MC  is all-around fast mid-sized British-style touring kayak designed for plywood building.
You have to make sure your panels are set to be developable in the layer menu, and you should also make sure that your error rate is low. I wish to build a kayak that’s easy to turn, must roll (low profile aft deck) and have some speed .
I can’t get my version of AutoCAD LT to work on this computer (windows 7) so I downloaded a DXF viewer.
James, I couldn’t get the pdf to print correctly, because the paper size is too long.
Even in the age of plastics it is still a great material for sailing dinghies, rowing skiffs and flat-water racing kayaks. Wood absorbs impacts, crushing forces and vibration which would shatter a plastic composite.
If you don't mind some extra time and expense, you can make a plywood kayak as tough (and heavy) as the toughest plastic one. On the other hand, an unsheathed plywood boat made of 4 mm marine ply can be half the weight of a fiberglass boat, very rigid and easily strong enough for estuary and fine-weather use, or more. Fortunately, some of the best Greenland kayak designs have a boxy cross-section which is perfect for simple plywood construction. If you were to cut a Greenland kayak in half at the middle you would see that the bottom is a very flat V-shape and the sides are nearly vertical. If you are building from plans, you will probably start by acquiring two large sheets of top-quality plywood 4 millimeters thick, and a third either 4 mm or 6 mm thick. 4 mm plywood usually consists of three layers of wood veneer, glued together in a sandwich so that the grain of each layer runs in a different direction to the layer alongside it.
At one time, you could be confident that plywood stamped with BS 1088 was of reasonable quality but lately there seems to be a lot of trash with that BS 1088 stamp. Exterior or marine plywood is often made from veneers of certain tropical hardwoods which have a natural resistance to rot.
According to WoodenBoat magazine, if you buy an Arctic Hawk sea kayak kit from Chesapeake Light Craft it comes with an instruction manual 457 pages long.
Use a boatbuilding adhesive such as urea formaldehyde resin supplied as a powder which you mix with water.
Then screw and glue a pair of long strips of wood, say 15 mm by 10 mm, to the top edges of the pair of panels that make up the top half of the hull. Before you stitch each panel to its neighbor, take a hand plane and put an angle (a bevel or chamfer) on the edges of the panels. Drill small holes every 3-12 inches around the edges of the panels that make up the bottom of the hull.
Put on gloves and use abrasive paper to roughen the parts of the panels you intend to tape. When you have done this to each panel, place the two bottom panels of the hull together, face to face, and simply tie them together using individual twists of wire. After taping one side of the hull seam you will remove the wire using wire cutters and taper-nosed pliers. Some people prefer to use just a few twists of wire and do most of the stitching with continuous nylon monofilament fishing line. Using a roll of glassfiber tape, half a liter of resin (mixing up a little at a time) and a paint-brush, tape the inside of the hull joints.
Some say that only epoxy resin will stick well enough to wood, but we find that polyester resin is fine for taping.
If you want a really tough kayak, cut out an extra set of plywood panels slightly smaller than the bottom hull panels and use epoxy resin to glue them inside the hull so that the bottom is 8 mm thick. Use stainless steel (not brass) screws and waterproof adhesive to attach a pair wood strips, say 15 mm by 5 mm, along the outside of the top of the hull.
If you like getting up close to rocks, it may be worth sheathing the lower part of the hull with fiberglass to give it some protection against gouging and impact.
If you want a really tough, durable kayak and don't mind it weighing 55 lbs or thereabouts you can sheathe it entirely in fiberglass, including inside the bottom of the hull.
You can buy a complete kit from the Internet including pre-cut plywood panels, copper wire, glass tape and resin, and a plastic seat.
You will probably still have to bevel the edges of the panels, obtain materials for sheathing, deck rigging and hatches, and decide where to fit them. Sean Hartman found plans for a skin on frame canoe (SOF canoe) taken from an old book some time ago. This seems like a good opportunity to mention that the scans from Practical Boat Building for Amateurs by as written by D Neison and updated by Dixon Kemp I put up some time ago include another set of drawings and instructions for making a canvas canoe. I used plywood for the center forms as well as the stem and stern pieces and red pine for the gunwals and ribbands. Have you got news for us?If what you're doing is like the things you read about here - please write and tell us what you're up to.
Classic Sailor is a new magazine about traditional and classic boats from ex-Classic Boat editor Dan Houston and colleagues that promises rather more coverage of the traditional craft around our coast. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Follow me on TwitterLooking for something?This is a busy weblog, and what you're looking for is probably still here - just a little way down the list now.
Our Faversham-based friend Alan Thorne can help with boatbuilding projects - constructing to plans in very tidy stitch-and-glue or more traditional techniques. It’s a great modern British-style sea kayak that a builder can scale down to suit his size.

It is really nimble, has a great secondary stability, was really fun to play in a rough water flow at 1400 cfs, where I use to train for white water (catch the eddy, peel out, etc) Sorry for the low definition of the movie. This kayak suits a medium to heavy paddler looking for good initial stability and with increased flare above the waterline lots of secondary stability. The SB was originally designed as a multi-chined boat for plywood building using the excellent HULLS software. I converted in centimetres and as it looks like the first column contains x axis coordinates and the second one, y axis coordinates. I’m a professional boat builder (fiberglass, ranging between 64-151ft) and have been dying to get into plywood boat construction. If I print the DXF at 100:1 will that allow me to spray-glue them down to MDF and have full scale patterns? It seems like the first reports are coming in on the builder forum and this sea kayak sounds like it paddles as well as the cedar strip version. It is tough, very resistant to fatigue and comes in a range of densities which makes it possible to select a material with exactly the right strength-to-weight ratio and rigidity or flexibility for most tasks.
Some of the world's best flat-water racing kayaks are still made in wood veneer by Struer Kajak in Denmark, because it can be used to make a more rigid, durable hull than plastic composite. Die-hard lovers of plastic and glass such as race yacht builders often use wood for prototypes, as a core material and in production boats for gunwales, transoms, backing pads, shroud plates and mast steps. A plywood kayak can be considerably lighter but a fiberglass one will have better resistance to abrasion, need no painting and be almost unaffected by water and sun.
He has used them extensively, mainly around the northern half of the South Island of New Zealand though he has paddled parts of NZ from Stewart Island to the mid upper North Island.
Avoiding surf launches as far as possible, he does not find it necessary to sheathe his kayaks with fiberglass. Where the bottom and sides meet there is a sharp angle called a chine, running nearly the whole length of the hull. It is nobody's idea of a good shape for a serious racing kayak, but many people feel it has have advantages for sea kayaks which do not aim at ultimate flat-water speed. Although intended for strip-plank construction, Bryan says it could easily be adapted for plywood. If you intend to use your kayak in exposed waters, it is worth getting really good materials.
In the USA in 2010 a single sheet of 4 mm marine ply mostly cost between $28 and $70 plus shipping. If you cut out a panel with a pointed end, the tip disintegrates before you get a chance to use it.
The only real way to be sure is to buy plywood made by a reputable manufacturer and sold by a specialist lumber dealer. If you buy them you make a direct contribution to destruction of the rainforest, especially if you buy plywood made of the true mahogany, Khaya.
Bruynzeel produces 4 mm and 6 mm gaboon marine ply as part of its Hechthout range, made from timber grown sustainably in Gabon. This is a little under half the length of most sea kayaks so the bottom panels of the kayak have to be made from two shorter pieces and joined together end-to-end. It is often worth covering the floor with a couple of sheets of cheap hardboard before you start. These are more craftsmanlike, but in a long slim sea kayak they are seldom better than butt joints. When you have assembled your four long thin hull panels, clamp corresponding panels together in pairs, back to back, and use a long hand-plane to reduce them to the precise size.
Generally the bevel is about 45 degrees but it is a more acute angle towards the ends of the panels.
The distance between holes depends on the force required to bring the panels together at that point.
From now until you have taped the panels, wear gloves when handling them so that oil from your skin does not get onto the surface where it might reduce the strength of the bond between glassfiber and wood. Copper wire is best, because probably some twists will remain permanently embedded in the hull. This has the advantage that when you have taped the inside of the seams, you can simply plane the outside of the seam flat before taping the outside. When the resin has set, you can remove the ties and surplus resin from the outside of the seams and tape them too.
They will help the hull keep its shape until the deck is fitted, support the deck, and create buoyancy compartments to make your kayak safe. These will protect the side panels against abrasion when the kayak is on the water alongside a dock. You could put an extra layer of fiberglass under the hull, three feet fore and aft of the seat, because that is where most rock damage happens. They seem to have been taken from an old book entitled Canoes, Dinghies, and Punts: How to build a canvas canoe by E T Littlewood.
I have plans to build two Greenland skin on frame kayaks as the first priority when we move into the new place.
Try scrolling down, clicking on the 'older posts' button at the bottom of this page - or try the search gadget! These free kayak plans are for builders desiring a skin-on-frame version of the boat built in Yost-style. The flare makes the secondary stability feel solid, so it’s easy to hold on edge for quicker turns. Was also looking at the Secret, but decided that she needed drag to stay below 5 at a little higher speed.. Also, if you mess up, you can start error over without chopping at the stringers or frames. I’ve taken the original file and used Delftship Pro to clean it up and fair the lines.
The only problem is that now I have yet another boat to add to my list of boats to consider building! I’ll be interested in seeing if the multi-chine hull retains the same charm as the rounded version.
SOF kayaks are much tougher than you might think, can be very light, but won't long withstand being dragged over rough surfaces.
It is very easy if you buy a pre-cut kit, in fact well within the ability of a practical 12-year-old.
Your editor's first kayak was a plywood one he built in his parents' living room and had a lot of fun with for several years before switching to fiberglass. He once used 6 mm marine ply for the bottom of the hull of a double kayak which did a 40 day circumnavigation of Vanua Levi, Fiji, but generally prefers 3-4 mm. My previous 3 mm kayak (no glass sheathing) has done ten years with lots of multi-day trips. You can bend it into a semi-circle; you can twist it into what is, geometrically, a section of a cone.

A baidarka may have a triple chine hull, with performance almost indistinguishable from a round bilge hull. To make the seams rigid and waterproof, lay fiberglass tape along each seam and brush plastic resin onto it. The design is not free but it's nice, and the plans come on paper from WoodenBoat magazine. It is too stiff to twist through nearly 90 degrees as required for the bottom panels in most kayak hulls, but it makes a very good rear deck. Beware bad plywood with outer layers of attractive veneer which are paper-thin so they add nothing to the strength of the core and you may go right through them when smoothing down your finished project; and core veneer(s) which are not smooth sheets of veneer but made up of lots of little pieces, of varying thickness and density with big core voids, cheap filler and even factory waste such as sawdust, paper and steel staples. Brands with a reputation for quality include the following: Bruynzeel, Anchor, Joubert, Shelmarine and Boulter.
It is very likely to be the result of destructive and illegal logging whether it is Khaya ivorensis or Khaya antotheca. To take advantage of that, make sure that the straight ends of the pieces lie precisely on the edge of the sheet. Cut gently and hold the saw as near horizontal as possible to avoid splintering the surface layer of veneer on the other side of the sheet. We get our copper wire by stripping a short length of industrial copper cable and unwinding the strands. Leave each twist slightly loose and use a screwdriver inside the hull to press the wire inside the hull down into the seam. This sort of sheathing is likely to add 11 or 12 lbs to the weight of the kayak, or 20 lbs if you also use epoxy resin to encapsulate all surfaces.
I plan 2 different underwater profiles to make SWMBO's somewhat more stable than the traditional shape. The plans suggest later on to go back and lighten the boat by cutting excess material away, which I figured was easier to do before assembly.
The stern stem is harder than the cedar strip version which helps with tracking, because you can’t add a skeg to this boat. The nestings give you each frame separated from the rest, so you just cut it out, glue it to the plywood and then cut.
Each frame is printed separately, so you can just cut out the frame and glue it to the plywood. The easy way to do this is just scale the deck, but with the frames, that makes it difficult to get in an out. The one personal requirement that I really wanted in my upcoming sof kayak build is to make a single chine boat. I’m going to begin construction within the next week or two and take detailed pictures and notes for you.
You can build a kit kayak in three four weekends, but accessories and painting take as long again. Plywood can be more eco-friendly than composite or plastic but that's not necessarily so. Even if your kayak is painted with epoxy resin and sheathed in glass, the wood will get damp and the glue of bad plywood may dissolve, causing the panel to delaminate after which it will have the strength of wet cardboard. A good name for quality does not always mean clean hands when it comes to the natural environment. You can get high-quality lightweight marine plywood made from sustainable softwood, mainly Douglas fir. You need a bevel only on the inside half of the panel, just enough to make the panels sit together easily when you stitch them together with twists of wire.
Some people report good results using very thin steel wire with a plastic coating, available from garden centers. You will use two to support the back and front of the cockpit and the other two about 16 inches closer to the ends. If you are making the decks from 3 mm or 4 mm plywood, consider cutting an extra panel to double their thickness around the cockpit. One problem though- the two center forms have very different shapes and the plans tell you to make rests for the ribbands in the forms. You still need to mark out your stringers and the curves between the stringers and the interior.
I wanted a bit less weight, build complexity, and really like the carving abilities of a more Greenland style boat. Consider using a Japanese handsaw as these cut when you pull the handle, not when you push, so the blade can be thinner.
The main butt plates will be under the seat, just where the hull needs extra strength anyway. If the panel edges are sharpened into a real knife edge, it may get broken during the construction process and will easily be damaged when you bump a rock at sea.
If you are building a design with a small cockpit, the deck beam at the front of the cockpit will also be your knee brace, as in this photo of the masik in a skin-on-frame kayak. In particular, just behind the cockpit, where the rear deck will have to support your weight when you get in and out, and for 3 feet in front of the cockpit if the front deck may ever have to support the crushing weight of a flooded kayak during a TX-Rescue.
I did all that prepwork before assembly which resulted with the square ribbands not wanting to rest properly in the shapes without some twisting. You need to add the cut-outs for the stringer size you’re using and you need to add the curves and center cut-outs.
You could easily construct a box with plywood, but if you wanted to construct a rounded bowl you would need a lot of glue and patience. A few people even find they can cut plywood panels precisely to shape, with none turned into sawdust, with a craft knife. Still, there is a certain satisfaction in making perfect scarf joints, and the only tools required are a ruler, T-square, pencil, a very sharp hand-plane, glue and a few clamps.
It may be a mistake to economize by using polyvinyl acetate (PVA) wood glue even if it claims to be strong and waterproof.
Notch the top edge of the deck beams so that they do not prevent you draining all water out of the cockpit when the kayak is upside down. The notches in the shapes do need to be cut out as you put the ribbands on or else use stock that is round and won't give you twisting problems- bamboo or pvc pipe were a couple ideas I had.
Unless you're very confident about your ability to cut precisely to shape, cut the panels out about 3 mm oversize all round except for the side which is going to join onto the neighboring panel. Notch the inwales slightly so that you can slot the ends of the deck beams into the notches, and attach the beams with screws and glue. On the disc I sent you will find a few skin on frame boats from Hobart, and a beautiful West Greenland stripper.
Because of all of this, I settled on the transom hitch lashings to keep those pesky ribbands in place and it has worked wonderfully.

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