homemade oar

for my raft race i have to make a homemade oar, kayak type with a blade at each end of a shaft, i have the blades made from pieces of a plastic barrell , shaped etc, however does any1 know a material that would be good for the shaft part, something that is strong ,light and rounded,
i think i will need it to be about 7.5 meters long, im hoping there will be something better than wood.

any help would be great , the help i received in relation to the raft was excellent.

 

hi

I have built 4 oars, and these are fairly good. Nothing wrong with wood!

7.5m or 7.5ft , 7.5m is long, I guess you would have a wide beam like 8ft or so to justify an 22ft oar.

Some things, blades work a bit better if curved, narrower and longer is better in a seaway, I kept on narrowing mine. The ideal for a 7.5ft oar is 12cm wide x 70cm length. I made mine curved with laminated plywood using a jig, worked well and was easy to do

Some other things, balance is important, in that you need weight in terms of heavy wood or iron weights added inboard of the rowlock in order to balance the weight. I put weights in the handle, but it would have been easier to add the weights externally on the loom, just a few inches down.

The handle should be hardwood about 30mm diameter (some use smaller) you can buy dowel this size. Add grease for your where rowlock socket pivots (assueming you are using rowlocks)

Leahters are really good, you can buy at a tannery or leather place. Soak in water before hand to stretch and then apply. Use stitching to secure the leathers. Buy a cheap $3 hole punch (the ones that work with a hammer and have a hole in them to let the leahter flow through)

Add lard to your leathers to reduce friction.

Rowing is fun and enjoyable. good oars are worth it.

If you are using a wide beam, then second hand sculling oars may work, as the rowers upgrade to newer flasher oars, there is little demand for the old ones, so possibly contact rowing clubs and ask if they have second hand oars for sale

 

you want a 7.5m kayak paddle?

Will not work, use oars they are much better. If you are talking a 7.5ft paddle then buy at kayak store

 

Pete he´s talking about a raft!

 

There is no way your idea can work. The problem is one of leverage, and there is also a problem with girth.
Addressing the leverage problem, you will find that two measurments matter; the distance between your hands and the distance from either hand to the blade. The difference between the two measurements make a ratio (in your case), of about 3.25 :1 (3.25m/1m). Conrast this with a kayak paddle at 2m overall length where the ratio is maybe .5m/1m. the longer raft paddle has 1/6 the leverage of the kayak paddle. Pick up a shovel and attempt to pick up a shovel-full of dirt with your hands in the normal position, and then at 1/6 of that distance between your hands.
The second problem of girth has to do with how large a diameter would be required at the hand-holds if the length of the paddle is as extreme as you mentioned. If in wood, the required girth (perhaps, guessing, 3 1/2") would be impossible to grasp without giant Sasquatch hands. In aluminum or carbon, it's hardly better. They would also be huge. No Earthly material I know of could be as small as 2" and not be too whippy and hence useless.
Use two oars, and you will do better.

 

Better than wood...

rickjames,

"Better" than wood? What's wrong with wood?

You could try aluminum pipe or thick wall plastic pipe.

7.5 meters, good luck with that one!

Tom

 

mistake

typo sorry 7.5 feet is what i was meant to say not meters.i think thats about the normal length for oars,
i won't be using row locks, my raft is only about 3 feet wide so normal type oar will do fine,
thanks for info, any more input very welcome

 

Rick,
I use a Windrush 14 foot cat as a yacht tender. Has a plywood platform. The oars I made from the upper sections of two piece windsurfer masts. These have timber extensions for the grips and rowlock leathers. The blades are plywood covered with carbon fibre and epoxy. Overall they are about 10 foot long. They get a slight spring in them where the fibreglass masts bend. Not perfect yet, I will shift the leathers down a bit to get a better ratio and have a slight cross over.

 

rickjames,

You didn't answer my question.

What's wrong with wood?

What do you think of my other two options?

Tom

 

pipe/alu great

i think the pipe /aluminium great ideas, just thought to get rounded wood wit the length and strength would be heavy. Am hoping to get pipe/alum tomorow

 

If you use the right wood then it won't be all that heavy. Not really sure what you can get easily in Ireland, ask at a fine wood workshop, they would know. In my neck of the woods the first thing I would reach for to build such a tool would be White Ash or similar wood.

Well made paddles from them aren't much heavier than mass produced metal and plastic versions, and I've seen them take far more abuse than light weight aluminum poles. If the aluminum takes any damage then it will bend and break at that point, the wood keeps it strength even after minor dings.

 

Really, a spruce paddle (of only 7 1/2 FEET) is completely adaquate, with a good strength to weight ratio. A lighter paddle could be made from carbon fiber but for the money, spruce is a true bargain material. Some other woods like ash are more durable, but ash is heavy.
Shaw and Tenny, the oldest oar and paddle maker in the USA (located twenty minutes from here in Orono, Maine) recommends ash where rough usage is expected. Otherwise, they specify red spruce for all normal use.
Few if any other woods come close to spruce (Sitka, Red, and a few other varieties of spruce top the list).
I've made spruce paddles and I've used both spruce and ash. In use, they seem to work the same (the spruce does have less inertia, for what it's worth), but when tossing them around, carrying, or using them to fend off, the spruce just can't be beat for lightness.

 

Wood

There you have it Mr. James, wood is the way to go. I'd go with yellow cedar but you're not going to find that in your neck of the woods.

I wasn't able to bring up the pictures of your raft but I hope you've got some good directional stability in the way of a keel or centre board as kayak style paddling is really going to want to swing you from side to side.

It's called yaw and it wont be your friend when you start paddling I suspect.

Nothing a vertical fin protruding down into the water wont help out with.

Long and skinny with a foot controlled rudder would be best. No rudder's okay too as your paddling can steer you.

Good luck, let us know how you make out.

Tom

 

thanks so much, you have all been very helpful

 

Old fibreglass SSB antena works well. You sometimes find them around dumpsters. Give them a coat of black paint to keep the fibres out of your hands, and keep future UV out.
Brent