Skin-On-Frame Outrigger Sailing Canoe. Chapter 3: Lash the Frame.




Introduction: Skin-On-Frame Outrigger Sailing Canoe. Chapter 3: Lash the Frame.

About: Tim Anderson is the author of the "Heirloom Technology" column in Make Magazine. He is co-founder of, manufacturers of "3D Printer" output devices. His detailed drawings of traditional Pacific I…

Take some bent sticks and some string and make a boat-shaped object.
We're going to take all those sticks and tie them together in the shape of a boat.
The keel and stems are tied to stiff T-shaped jigs to hold them in the proper shape.

The stringers are 3/8" x 3/4", the ribs are green branches from Kiawe (mesquite) trees as thick as I could make them without breaking during the bending process, which is about 1/2" thick.
There are 20 ribs. Each is lashed to the keel in the middle. They are also lashed to 5 stringers and 1 gunwale on each side. That's 13 X 20 = 260 lashings you're going to do. Think of it like knitting. It's going to take some time, even if you could do a lashing each minute. Get a good comfortable work environment and some good books on tape to listen to. Or some friends to talk and help. It goes a lot quicker with more hands. It doesn't make much mess or noise, so you can take your frame with you to any shady/secluded/sociable spot that suits you.

In this photo you can see some of the "bowstrings" that pull some of the ribs into the proper shape.

Continues from
Chapter 1: Make the Deck, Keel, and Cockpits. and
Chapter 2: Make Ribs

This episode is followed by:
Chapter 4: Carve Outrigger and Break Tools and
Chapter 5: Hull Frame Finishing
Chapter 6: Morton's Oar
Chapter 7: Sew a Skin over the Hull Skeleton and Seal it
Chapter 8: Keel and Rub Strips
Chapter 9: Dipaakak
Chapter 10: Independent Suspension
Chapter X: Maiden Voyage

Please support the WAM canoe project as they preserve and foster canoe knowledge in the Marshall Islands.

Step 1: Set Up the Wickets

We mark the gunwales with a line every 7.5" to place a rib. Set up all your ribs and eyeball them.
Star trims a rib to proper length with the pullsaw and knife. Each rib has a thick end and a thin end due to the taper of the stick they are made from. That's not a problem. Flip ribs around so thick and thin ends alternate on each side of the boat.

Don't get too carried away with perfection yet. Just eyeball the ribs and make sure they're long enough and not too deformed for your type of reality. We're setting them up just to make sure there are enough of them. You might need to go back to episode 2 to cut and bend some more ribs.

Step 2: Stringers

The 5 lengthwise sticks tied to the side are called "stringers".
Clamp a few of these on each side or tie them on with innertube as seen here. They force nearby ribs into an average shape, and make it easier to see how a rib needs to be trimmed. If a rib has a wrong bend, you can force it by tying it with a string across the wide part. Kind of like a bowstring.

The middle 8 ribs are identical on my canoe. That makes it easy to get them right.
Each of these ribs measures 52.25" with a dressmaker's tape pulled around the outside from end to end.

Why are the middle ribs identical? Because I want a flat spot at the middle of the keel. I'm inspired by some Marshallese racing canoes I saw at the National race in 2000 at Majuro Atoll.

The other ribs are trimmed to press lightly against the keel. If a rib is too fat I trim it a little shorter or tie across it with a bowstring at the fat part. If It's not fat enough I leave it longer. I tie it to the stringers to pull it out.
The stringers force adjacent ribs into an average shape.

Step 3: Cut Many Pieces of String

We'll tie all the ribs to the gunwales with string. I had some 1/16" braided polyester leech line. Fishing line, kite line, or anything else would work.

I tied a few to figure out how long the string should be. A 22" chunk is perfect for 3 times around the rib. It makes it easy to pull tight and retie. Cut two such strings for each rib.

Star pounded two nails 22" apart and wrapped the string around them. Then she cut the loops at each end and melted the ends with a lighter.

If you don't have spectra or polyester use whatever you have. If you use nylon soak it with water before pulling it tight, or it'll get loose later when it does get wet.

Step 4: Drill Holes for Gunwale Lashings

Drill two holes to tie each rib to the gunwales.
Use a backing block as shown so the exit wound won't splinter.

Step 5: Lash Ribs to Gunwales

I started on the inside, wrapped the string around the rib twice.
So when it's tied, the string circles the rib 3 times.

I pulled it tight before tying a knot. After my fingers got sore I used pliers to pull them tight.
I tied them with a modified square knot. when you tie the second half-hitch go through twice instead of just once. That's what worked best for me anyway. Use whatever works for you.

I got carried away and tied all of them. That was a mistake. I had to untie most of them later to trim and adjust the ribs.

Step 6: Rib Lacing

I cut a wide wooden wedge to compare stringer spacing. I'd see how far it fit into the gap between stringers. I'd shove it that far between the next pair to keep the lashing from pulling the stringer too far to one side. This photo also shows the basic path of the string to lace a rib to a stringer.

Step 7: Rib Lacing Steps

Wrap a handy quantity of string onto a stick.
Pass it over the stringer, behind the rib, and back over the stringer again. Pull it tight.
Now we're going to lock those turns in place by wrapping the string over the incoming tail, and around the other turns of string as shown.

Now continue to the next intersection between rib and stringer and repeat repeat repeat.

If you're feeling creative or erratic, you can use different numbers of turns.
I used more turns when it took more force to pull a rib out to the stringer.

To start or end a series of lashings, use whatever knot you like.

Step 8: Lash Ribs to Keel

Keel lashing is the same, but with more turns.
Actually, you'll probably want to lash the keel first and then do the stringers afterward.

Step 9: Stringers to Stems

I drilled some big holes in the stem boards to tie the stringers there.
I used a quarter-round router bit like a countersink to round the edges of the holes.

Step 10: And There It Is.

The skeleton is much stronger and better looking than expected.
Bystanders make approving comments. I could wrap plastic around it and put it in the water right now, but those 260 lashings have gotten me into a really methodical state of mind.

The bend at the end of the stringers is pretty tight. I thought I might break the stringers, so I didn't cinch them down all the way. On the north coast of Papua I saw boards being bent for canoes just above the beach. The ends are the most work. They pile stones on the ends and lash them to take the sharpest bend they can. In the old days the end was a separate piece carved from a forked tree trunk. That was more work but didn't involve bending anything. The canoe builder said now that boards are easy to get he saves work by making the ends of his canoes thinner, but the old shape was better.

I'm trying to make these ends nice and fat. A naval architect would say "a high prismatic coefficient".
I had to go back to the mainland so I just trimmed the stringers to length and left them like this.
When I get back I'll see if they've taken the bend enough to lash down against the stem.

If they don't I'll do one of two things: I might bend new ribs for the ends that aren't so fat.
Or I might cut the stringers short so they don't reach the stem. Some kayaks and Umiaks are done that way.

I tied cord loops to the rafters and hoisted the canoe out of the way til I got back.

Continue the adventure with Sailing Canoe Chapter 4: Carve Outrigger and Break Tools

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    12 years ago on Introduction

     What are the dimensions of the stringers? Thin enough to bend well and thick enough to be structurally sound?


    Reply 12 years ago on Introduction

    I used to teach a class on skin on frame boat building, easiest material I found was cheap mahogany door skin. It's about 10 bucks at Home Depot and is good for 20-30 strips (depending on width) after some easy ripping on the table saw


    Reply 12 years ago on Introduction

    Thanks for asking! thats the sort of info that's important to have in the right spot. says:
    The stringers are 3/8" x 3/4" x 16' which is longer than we really need, but we got lucky with boards. We'll cut them down later when we fit the skin on.
    I've updated this step to include the info. I haven't updated my culture to use the Metric System, it will take a long time to undo the damage done by Ronald Reagan, who switched us back into the Imperial System.

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    Reply 12 years ago on Introduction

     Thanks for the update. So one could use a 1x12 clear cedar or pine board (however long) and rip it down to 3/8"strips to use as stringers and ribs? I really would love to build a canoe like this, I recently moved to Oregon and it just seems heretical to live here and not have a canoe. I have access to a very good woodworking shop, I'm thinking I could cut out my strips of cedar or pine, soak or steam them, and manhandle them into a canoe, obviously with a little more finesse than that. My concern is: Is it necessary to use saplings or willow rods (as i have seen many others do) for the ribs? Wouldn't a thin and supple strip of softwood work just as well and have the advantage of perfect consistency?


    Reply 14 years ago on Introduction

    Nice! how do you like it? is there more information? I'd love to hear about what did and didn't work for him!


    14 years ago on Introduction

    This is a cool instructable but it looks like Star is doing all the work.