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December 14, 2005

Building an Outrigger Canoe

My main pretext for coming down to visit Rick in Bocas was to build an outrigger canoe out of balsa wood. When he was in Canada in April we had checked out some of the boats belonging to a Vancouver paddling club. Looking at the boats, he mentioned that it would probably be possible to build a similar model out of balsa wood at his farm in Panama. I was intrigued by the idea, and mentioned that for a while I had been thinking about doing a paddling trip on the Amazon river and would prefer to travel in a paddle boat made of local materials. If only we could use his farm as a home base while building a prototype wooden outrigger canoe that would be able to hold two people and some luggage....

We met again on Oct 10th in Turrialba, Costa Rica to run a little whitewater and then travelled together down to Bocas. Once on the farm, I met the workers and was able to get to know them fairly quickly due to an impromptu session of water trampoline wrestling when they came by to visit with Rick. This was actually quite valuable as I would be working closely with them to build the boat. In fact, the extent to which I would rely on them was considerable.

The main people that I worked with are Man Hing, Emiliano, and Abelardo. Man Hing is the caretaker of the property and lives here with his family. He has a lot of experience building pangas (motorboats built of wooden slats) and cayucos (dug out canoes that may or may not use an engine, up to 42 ft long). Emiliano is his younger brother, who is also good at working with boats and is very skilled with woodworking tools. Abelardo is the chainsaw master, and can turn fallen tree into decent 2X4's using just that one tool.

We decided to use balsa wood because of it's buoyancy and because it would be easier to work with than one of the hardwood trees. Also, this being a prototype boat project, we didn't want to waste good wood. The balsa we chose had a base diameter of about 2 feet and was under 15 years old. It was growing at the very back of Rick's property, in an area overgrown by heliconia (a tall banana-like plant). This area had to be cleared anyway, because the small nispero trees that had been planted there were being overcrowded and there wasn't enough sunlight. 

The first obstacle that we ran into was that Man Hing didn't think that the tree should be cut down for another two weeks because we were at a bad stage in the moon cycle. There is some validity to this - apparently there are certain bugs whose life cycles are dependant on the moon and the amount of light that there is at night. We were just coming into the full moon, and his concern was that the bugs would be more active and would eat the fallen tree more quickly. We spent some time talking to him, and eventually the three of us decided that if we worked quickly on the tree after cutting it down, we would be able to carry it down to the water a few days after it was fallen, so minimal damage would be done by the insects. The tree was cut down the next day.

When the tree had been falled and we were able to measure it, we realized that the main trunk was 2 feet shorter than we had estimated, so the canoe would have to be a bit shorter than planned. Man Hing and Abe immediately went to work taking off the "top" of the canoe. They usually do this by simply making a long flat cut with the chainsaw, but because I wanted to boat to be raised at the tips they used an axe instead. The general idea at this stage was to take as much unnecessary weight off as quickly as possible so that we could drag it down to the waterfront where it would be easier to work on and there was access to electricity for the power tools.

Measurements were made using a string that had been soaked in used oil and the inside of D-cell batteries - it was run down the length of the trunk and then flicked so that it would mark the wood. 

The outer edges were outlined with a piece of heliconia branch with the leaves cut off. This gave it a nice symmetrical curve and was incredibly simple and practical.

Dragging the boat to the waterfront took a lot of effort. Fortunately, most of the distance was downhill and if the trail was clear enough things went well. The uphill parts were pretty tough.

A branch from the same tree was cut off for the ama (the "outrigger" part of the outrigger canoe).

Once the boat had been transported it was time to refine it. Man Hing and Emiliano did most of the work here, using a chainsaw to trim off the rough excess and then working with an adze to smooth it out. It would have been neat to have done this myself, but they're just so good and efficient at it that it didn't make sense for me to do it. Bit of a shame, really - next time I'll insist that I get a turn  =P  As it was, I did a bit of sanding and worked with a hammer and wood chisel.

The original plan had been to leave solid blocks in the hull for the seats and foot supports and the rest would be hollowed out to make the boat lighter. In the end, though, it made more sense to take out the foot supports and replace them with wooden slats that were nailed in. It would also have been better to have done the same with the seat. Not only would that make the boat even lighter, it allows the water to flow and pool in one area where it's easier to bail.

The iakus (wooden bars that support the ama) are lashed to the boat using rope. They sit along a flat wooden surface with a pegs to keep them seated in the right position. The ropes run through holes that were burnt into the hull using a hot piece of rebar. The burning process seals the edges of the hole to make it strong, but most of them are reinforced with a short length of PVC tubing just in case. The danger is that the string, which is pulled very tightly, could tear up through the top of the hole and damage the wooden support (balsa is quite soft, and the string is relatively thin and runs with the grain of the wood).

Lashed together, the boat runs incredibly well. It "feels good" - ie. it tracks well, steers easily (paddle steering, no rudder), and the weight is balanced. The iaku sits nicely in the water and gives plenty of support to the hull.

Man Hing made a beautiful strong replica of my wooden bent-shaft outrigger paddle out of a slice of hardwood. The wood already had the perfect curve in it, as it was cut from the joint where the branch met the trunk.

Before being fully functional, the boat still needs a canvas covering over the ends because even small surf can break over the tips and flood it with water. In this picture where I'm approaching the beach, you can see how the back end is completely full of water and I'm being pushed by the wave rather than surfing it. It's disappointing that I didn't manage to get this completed in time, because the boat feels like it will surf really well.

Another problem is that the sides of the boat are too low, and with the weight of two people it tends to, ah... become a submarine. Which is how at one point, Rick and I ended up paddling out into some big surfing waves, got the boat full of water, and ended up being pushed over shallow coral with the edges of the boat sitting two or three inches below the surface of the water! So next time, higher gunwales, lighter seats, and more bouyancy.

Sooo... Rick has this great idea of doing a 200km hike from Colon to Bocas (or Bocas to Colon), along the Carribbean coastline. MY idea is to do the trip in an outrigger instead. The boat would have to have considerably higher sides and a good canvas covering, but the basic design would be the same. There's plenty of gear space, and it's a very versatile craft. If you want a new, differently shaped ama or iakus, it's just a matter of how good you are with a machete! Boat leaking? Fill it with wood chips and glue! Anyhow, that would be a super-cool thing to do, so if anybody's interested let me know. It would be great training for the Amazon trip....


Posted by rick at December 14, 2005 08:22 PM