Intro: Bamboo Windsurfing Rig
This Instructable shows how I made a windsurfing rig from bamboo and an old Laser sail, using only some basic hand tools and materials I had lying around.
Why would someone do this, you might think? It all started when I found an old windsurfer board at the local dump/recycling place, I bought it. But you can't sail without a rig. In my country there's no Freecycle or craigslist, besides, bamboo is much cooler anyway. I built this without using any power tools and so can you. You'd be surprised how much fun a hand drill is :-) No tools and supplies list most of the time because on a project like this it's important to 'wing it'. Be creative and use whatever you have lying around taking up space.
I sometimes ramble a bit so if anything is unclear check the pictures!
(Ok I'm kind of lying. An electric sewing machine was used to modify the sail. So that's a power tool).
Step 1: The Sail
For this project I used an old Laser dinghy sail. It was what happened to be available at the local dump/recycling place, but any small boat sail that has a mast sleave will do (Topper, Micron etc.) If you go for a different sail then you will have to change the dimensions to suit.
Unless you are a giant or windsurfing pro, you will want to make the sail smaller. In my case I didn't have any really long bamboo for the mast, so that decided on the dimensions for me. Besides, having a small sail means you can use it in almost any wind, and I can let smaller kids at the sailing club have a go. Having said that, I do wish it was a little bigger :-) So I'll make another one!
After deciding on the size, cut off the sail. Scary, but it has to be done. Sew the bottom edge (foot) of the sail. Now two new eyelets and a gap for the boom need to be added. The gap is easy, just cut a short section out of the mast sleeve, making sure to leave the stitching holding the mast sleave in place intact. Then sew the edges. Make the gap bigger than mine, about 30cm, this lets you adjust the boom up and down.
Before the eyelets are added the corners need to be reinforced. There will be a whole lot of sail material left over for this job. Look at the old tack and clew and copy what the pros did. Or let your mum :-) Instead of using grommets I sewed metal rings onto the sail. One was a random ring, the other a very strong key ring. They are both starting to rust though. Lay the ring onto the sail and draw around the inside. Cut a big X, then another one at 45 degrees to the first. Fold the little triangles over the ring and sew around using strong thread.
You might also need to make some battens for the sail, I just used bamboo.
Step 2: The Mast
The mast is made out of bamboo. It's strong, it's light, it's beautiful and it's free!
The mast is 3.91m long. It's important that the bamboo is cut off just above a node, and that the inside diameter at the base is 36mm. A little larger could probably be used as well, with some imagination. (This is because the universal joint uses 36mm outside diameter pvc tube). Don't worry if the bamboo tapers a lot. Mine's only about 25mm diameter at the top of the mast, but has so far proven to be strong enough.
A crack in a mast like this would be disastrous, so some anti-crack tactics are employed. First of all a little hole was drilled inbetween each node. This is to stop the expansion of hot air cracking the bamboo if left in the sun. A little piece of electricians tape was put over each hole to stop the mast filling with water, which would make it too heavy to pull up, and probably rot the bamboo too. At the base of the mast jute garden twine is wrapped around tightly and then some drops of superglue are dropped on to stop the twine moving. Before doing this you should sand the bamboo to remove the waxy coating.
Step 3: The Wishbone Boom
This is the bit you hold on to when sailing. You will need:
- 2 Pieces of bamboo, 2m long and about 35/40mm diameter. Make sure to test them for strength first. I did this by tying to a tree at both ends and then leaning like I was windsurfing in a strong wind. Cut them so that there is a node at the thickest end.
- A piece of wood about 3.5x4.5x46 cm. This acts as a spacer at the front of the boom, it holds the 2 bamboo pieces apart so they don't touch the sail (as much). Let's call it the front piece.
- 2 Small blocks of wood. About 12x3.5x2cm. These will be the boom jaws, they help locate the mast.
- 2 Large nails, I used 90x3.55, according to the packaging :-)
- A bit of rubber/innertube. I used some of a tractor innertube, it's some very thick rubber. Used as a padding for the jaws.
The first thing to do is shape the ends of the front piece so the bamboo fits in snugly. I put it in the vice and used the saw to cut a shallow v. Then I cut two more little shallow v's out of the side of that. And then I attacked it with a chisel, a knife and sandpaper until it fit the bamboo reasonably well.
Next shape the two blocks for the boom jaws, you could leave them pretty much square, or make them curvy like mine. This was done mostly with a saw, a knife and a chisel. I didn't sand them because I liked the carved look. Have a look at the picture to see where they go on the front piece. To figure out how far apart they need to be you will need to figure out how high you want the boom to be on the mast first. I have mine about 1.3m up the mast. The mast should fit with about 5mm on each side. This is to allow the boom to move a bit without crushing the mast. The blocks are nailed and glued to the front piece.
The best thing to do next is drill two big vertical holes through each end of the front piece. Start by drilling a pilot hole using your trusty hand drill, then use the brace with a big drill bit to make it larger, about 10mm. (Well if you insist on using you electric drill, I suppose I can't stop you. But it just isn't the same). These holes will be used for lashing the bamboo to the front piece. For this reason you have to round out the top and bottom in the direction the lashing will go. Have a look at my pretty drawn diagram. I did this using a few good whacks with a chisel, then a little sandpapering.
Before you attach the bamboo to the front piece it's easiest to first join the other ends together. This makes it easier to keep everything in place and ensures that everything will align. Simply lay the ends on top of eachother and drill through both (make sure it's the skinnier ends, to keep weight away from the far end of the boom). Then tie them together. I added a ring cut from inner tube to stop the knots coming undone.
Now align the front ends of bamboo with the front piece. Use an innertube to hold in place temporarily. You will need to find a drill bit that is the same diameter as the big nails you have. Drill through the bamboo into the front piece, making sure you miss your two lashing holes. Repeat on the other side. Now wack in the big nails. Suddenly you have a wishbone!
For added strength lash the bamboo to the front piece through the holes. Use your garden twine. (This is experimental, I'm not really sure how long it's going to last but it's easily replaced anyway.) Start with a couple of wraps, you can add a drop of superglue to stop the twine slipping. Make sure to do it tightly. Keep wrapping until it looks strong enough. Then finish off with a drop of superglue to hold in place, and then some more drops of superglue to stop the lashing moving. Now do the other side. Next I brushed on linseed oil, to try and stop water damage, somehow. To protect the lashings from sharp stuff staple on a strip of innertube to cover them.
Finally a rope is added as outhaul (this holds the corner of the sail). Just loop it around one of the ends of bamboo.
Step 4: The Universal Joint
It took a few tries to get this one right :-) The universal joint joins the bottom of the mast to the board. The mast has to rotate freely and also be able to lie flat on the water without flipping the board. Many string variations were tried but eventually it's just not worth the hassle, not to mention bruised shins! I gave in and bought a pack of two galvanised eye bolts and nuts, 38mm, 10mm eye diameter. This is the only item bought for this project. Other than this you will need;
- A bit of broom stick. This is the bit that connects to the board, you'll only need about 4cm so just cut it off an infrequently used garden tool and nobody will notice. More modern boards use a different connection I think so you might have to improvise.
- A piece of pvc tube, it's 36mm outside diameter. It will go into the bottom of the mast (which is why the mast needs to be 36mm inside diameter).
- A little block of wood, about 2x3x3cm.
- Some large washers. I had two that fitted exactly into the pvc tube, which is a bonus.
- 2 small screws or bolts.
- An icecream container lid (or equivalent) and a candle.
Shape the broomstick bit to fit in the windsurfer connection. For me this just needed a groove all around it. A sort of metal prong on the board holds it in place. Drill a hole through the centre just smaller than the eye bolt diameter. Add some glue and a washer and screw in the eye bolt.
Shape the little 2x3x3 block of wood to fit into the pvc tube. Drill a hole through the centre and check to make sure an eye bolt will fit through with enough room on the other side to add two interlocking nuts. If not your block is too big.
Bend open the second eyebolt using a vice and pliers and close it around the first, so they interlock. Add a washer to the eye bolt. Cut a washer from the icecream container lid, make it about the same diameter as the pvc tube. Rub candle wax onto it to help it turn smoothly. Add it also to the eye bolt, then add a large washer, then the block of wood, then another washer and finally two interlocking nuts to seal the deal. Make sure the eyebolt is free to rotate, or else your joint won't work.
Insert the block of wood into the pvc tube end. Drill into it from two sides and use 2 small screws or bolts to keep it in place. The problem with this arrangement so far is that if the eye bolts end up in the position shown in the 4th picture, the joint isn't free to move anymore. A flexible spacer is needed. Meet my friend innertube. Wrap a strip of innertube reasonably tightly around the joint. Then use two small rings cut from an innertube to hold it in place. Do this by putting it around, twisting it once, then putting it around again. Ask a girl with long hair :-) These rings are to avoid a knot which would get in the way of the mast laying flat.
Insert the joint into the end of the mast, and drill through from side to side. Make it a fairly big hole, to make threading a rope through easy. This rope will be the downhaul. Use a rope that holds knots well, not a cheap plastic one. The downhaul also keeps the joint in place. It's not glued or screwed. This makes it easy to remove if something breaks. All done! Amuse yourself by wiggling it side to side.
Step 5: Putting It All Together
Before use coat all wooden items in linseed oil, also the lashings.
Insert the universal joint into the mast, and thread the downhaul rope through both. Now insert the mast into the mast sleave. Tie the downhaul through the tack of the sail, the more wind there is the more tension you want.
Put on the boom, at 90 degrees to the mast. Lash it in place using a thick strip of inner tube. Get it really tight, but don't put in a proper knot. Just tuck one end under the other, friction does the rest. Really, you don't want to be untying this with wet cold hands.
Tie the outhaul through the clew of the sail, tension until the sail looks about right, the more wind there is the more tension you want, again. Insert battens in the sail.
You will need an uphaul rope, which is used to pull the sail up out of the water. It needs to be thick, floating rope, with plenty of knots in it, or braid it. Tie it from the boom to the tack, with enough slack to allow you to use it to pull the sail up.
That's it, you're all set to go! The sail performs well, and I tought myself to windsurf with it. (Well, still learning). Last weekend had it out in 15-20 knots and could keep up with a laser. I'll try to get some sailing pictures soon.
Step 6: Video!
Here's a slightly grainy video showing the rig in action. Proof for the non-believer. This is probably my 4th time windsurfing or so and there's not that much wind. As soon as I get some action footage I'll be sure to post it here!
Now go forth and create...