Sailing Canoe Chapter 6: Morton's Oar

Steering oar for a Marshallese racing canoe. This is a copy of an oar made by Morton Jikit of Namorik Atoll. He won the Marshall Islands national sailing race in the year 2000 with it.
It's 104" long and 7.25" wide at the tip.

Continues from
Chapter 1: Make the Deck, Keel, and Cockpits.
Chapter 2: Make Ribs
Chapter 3: Lash the Frame
Chapter 4: Carve outrigger and Break tools
Chapter 5: Hull Frame Finishing

Followed by:
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

Important things to get right:
You must put a big flat spot on this oar where it rests on the side of the canoe. There has to be a corresponding flat spot on the canoe there. I didn't do that on my first oar. I kept straining to keep the oar straight while sailing. As a result I got severe tendonitis in that elbow and mostly lost the use of my right arm for about a year.

The blade needs to be heavy. If it's too buoyant it will try to float up out of the water and you'll have to keep pushing it down, which is extra work.

Here's Morton working on a new racing canoe on Majuro Atoll in the year 2000.
He's using a piece of pvc tubing as a batten to make sure he's drawing a fair curve.
That's me in the hat, he's kindly invited me to do some adze work on the side. I was pretty nervous not to mess it up. The log is from a senile breadfruit tree that stopped bearing fruit. Breadfruit wood is a lot like cedar, lightweight and rot resistant, but less prone to splitting.

That adze might be very old. Blackbirders and pirates raided the islands in the 1800s. After that the islanders would attack any ships that came near. One of the ships they captured carried a cargo of tools. They've been passed down in families ever since.

Morton's native Namorik Atoll is small and has no reef pass. The men get up in the dark and troll for tuna in one-man sailing canoes. Flocks of birds chase the fish. The canoes chase the birds to find the fish. The birds and tuna move very fast, 30mph or more and move in unpredictable ways. This gives the sailors daily practice in highly competitive sailing.

Morton kindly let me measure his oar and answered my questions through a translator.
He only speaks Marshallese. He's an olympic level athlete of traditional sailing.
The more involved someone is with canoes, the less likely they are to speak English.

Marshallese canoes are designed according to rules of idealized proportions.
I don't know the rules for this oar because I didn't know enough to ask.

Here's what I deduce from these measurements:
This style of oar starts with a hardwood blank that tapers straight from the tip to the handle.
The length of this oar is half the distance between "Repakak" (yard sockets at bows) on his canoe.

Here are the measurements. Connect those points with straight lines. Curve them a little bit where the handle meets the blade. The edge of the blade is rounded down to a 1/8" thick flat edge.

Height Width Thickness
2.5" 7 1/4" -
12" 6 3/4" 5/8"
24" 6 1/8" 5/8"
36" 5 1/2" 7/8"
42" 4 3/4" -
48" 3" -
104" 1 3/4" 1.5"

There's a hole for a lanyard rope 38" up from the tip, 1.3" from the edge of the blade.

Morton carved his oar from a single plank of mangrove wood.
I didn't have any planks of hardwood big enough, so I built one up from smaller pieces.
I made the handle lighter, out of some clear Fir. I'll find out in practice if that was a mistake or not.

I scarfed fir handle section to the eucalyptus blade portion, to make a full length piece about 9 feet long. I cut a 6:1 taper scarf on my homemade tablesaw and improved it with a disc sander.
I mixed some epoxy, thickened it with white flour, and coated the mating surfaces.
I drilled and set a nail through the joint so the pieces wouldn't slide.

I was in a hurry for it to cure so I put it on top of an incandescent lamp to heat up and kick off the epoxy. I threw some towels over the top to make an oven. I kept poking at the glue squeezeout to see when it got hard. It took about 15 minutes to kick off fully. If you overdo this sort of thing it will bubble and you'll get an ugly weak joint.

WARNING
Do not do this with a halogen lamp or you will cause a fire.
Do not leave any kind of lamp unattended like this.
It will burst into flames as soon as you walk away.

I got some heavy tropical hardwood floorboards for cheap from the Habitat for Humanity "Re Store". I sawed them into proper shaped slats to assemble into an oar.
The tongue-and-groove and other odd floorboard grooves made it a tricky task.
I laid them together in the proper order.

Then came the tricky part.
I slathered the mating surfaces with epoxy thickened with white flour.
I didn't have proper clamps so I tied the bundle of slimy sticks together with bicycle innertube. I lashed a stick across the blade so the whole thing wouldn't just fly apart.
I shoved some wedges under the innertube bindings here and there to shove the laminations into place and keep them from sliding to one side.
I kept checking to see that the assembly hadn't gone wrong. I moved and unbent it to make sure the handle would cure straight.

I got up in the dark to check it and take the bandages off.
It had turned out pretty well.
The epoxy was still curing a little bit, so the innertubes pulled off okay and I can reuse them.

Watch out for epoxy cuts. When it cures against a piece of plastic or innertube and you pull that away, you can be left with a protruding razor sharp blade of epoxy.

The right way to shape something is to keep the corners square as long as you can.
Otherwise it's really easy to make things lopsided.
First shape the thickness and width outlines before you do any other shaping.
I marked the outlines in pencil. Then I used my Japanese pullsaw to trim the outlines.

The saw was a bargain. I bought a replacement blade for cheap and made a handle for it.
The fine teeth are for crosscutting and the big teeth on the other side are for ripping (sawing with the grain). It really matters if you use the right teeth for the job.

I started thinning the blade with my revived plastic Black+Decker planer. It made a funny smell, so I babied it and tried not to overheat it. It hiccupped a few times. I looked inside the cover. The brushes were flaming out. I tried to spin it with no load. No luck. I turned the blade with my finger. Bad idea. As soon as I took my finger away the blade kicked and spun. Damn. I'd left the trigger locked down. That was a close one. I don't think I'll use that tool anymore.

I went to a pawnshop and bought a beltsander and an angle grinder. They didn't have any planers. There's no such a thing as a used planer on the island because surfboard shapers use them up.

I bought some 50 grit belts and disks from Maui Laminates. I get a good feeling whenever I go there. They don't mess around.

I rolled a fleece airline blanket into a tube and tied the ends to make a dust collector for the beltsander.

The beltsander is a wood hog from the age of well made tools.
Unfortunately the pressure plate is broken off, as is the knob for adjusting belt tension.
I just about filled the dustbag when the sanding belt broke. It wouldn't survive the kind of pressure I needed to use without the pressure plate. I'll have to get some replacement parts before I use this one more.

The angle grinder from the pawnshop was the next contender.
No guard, no side handle, and a sketchy looking extension cord. Scary.

It's very easy to wreck yourself with one of these. Not to mention it's hard to sand anything smooth.
At least I had a good 50 grit disk with proper backing plate.

I moved my "workbench" out into the yard to make the dust storm.
I padded the clamp with some excelsior (http://www.thefreedictionary.com/excelsior that's really what it's called) put on my dust mask and safety goggles, and went to town. It worked pretty well.

It was pretty intense trying not to gouge the work or myself. The grinder had a good motor and did okay, but the gearbox got hot when I loaded it down. Bevel gears in a right-angle gearbox aren't very efficient for power transmission. I've hear that as much as 5% of your car's power is lost in the differential, which is also a right-angle gearbox. That lost power turns to heat.
This one probably needs re-packing with grease.

The blank wasn't thick enough for any errors. It ended up pretty straight and smooth.
I made a big dust storm and a thing that had the right sort of thickness taper to be a steering oar.

After the thickness taper is right I cut bevels on the corners with my crooked knife. That's the proper way. If you try to carve it to a circle immediately it will be malformed. The right way is to shave to an octagon, then cut those 8 corners to sixteen. I did that, then back to the disk to feather the corners smooth. No pix of that because it required total concentration.

Then I rubbed it all over with a piece of 80 grit paper, and the shaping is done!

My dad once showed me a Swedish family carpentry trick:
Wipe a piece of wood with water (or saliva-wet finger) to see what color it would be when you varnish it. A few raindrops and drops of sweat had showed me that this wood would look great.

I'd used up all my paintbrushes with epoxy, so I cut a swatch of rag and used that to wipe the oar all over with linseed oil. It looks good. And if the boat were ready I could take it sailing right now.
That's yet another great thing about linseed oil.

I left the handle unfinished. That's traditional for gringo oars. Supposed to be easier on the hands. This oar gets thrown in the water as part of the sailing routine. I don't know how wet bare wood is on hands versus varnished. I guess I'll find out and either leave it or varnish it.

TO BE CONTINUED...
Chapter 7: Sew a Skin over the Hull Skeleton and Seal it.