PVC Pipe Oar Design

Thanks for posting this!

That trapezoidal shape is used by Piantedosi on their wood oars. I may use this type of shape. See
http://www.boatdesign.net/forums/boat-design/oar-design-8-douglas-fir-46029.html for more on my new approach.

I do plan on laminating the shaft from rippings off of a 4x4 Douglas Fir post. We have these available here in 8' lengths for less than $10

 

The gacooarlocks site certainly makes sense.
Of course it duplicates the ideas used in the oarlocks and oars sold on the Concept 2 website.
One of the bothersome things about web quotations is that it is almost impossible to see when the idea came about, so you really can't give credit to whoever was first.

Personally I really like the use of flattened sides to help control blade pitch in the water. It makes up for my lack of skill.
The Concept 2 equipment allows for quite fine control of the pitch in practice (internal to the oarlock).

 

I never liked captive oarlocks on a utility skiff. Thole pins or offset open oarlocks work best for me. I like to use oars as boats poles and general tools.

Doug fir is OK if you can get it. Ive always used wood called Lumberyard Spruce. I dont know what type of spruce it is but,, its used for house construction work. Good grain structure and small tight knots.

To rapidly build a pair of good oars I still prefer to laminate two planks of 1 x 6 then band saw the shape out and finish tapered square sided . Fast build time.,

The shape of the blade should be how you use the oars. For A long stroke in flat water and I prefer narrow blades that slip. for upwind in a chop i prefer short power stokes and large blades .

Pet culler oar pattern...http://riverswest.org/Pete_Culler_Oars.pdf

Varnish is a waste of time. I prefer bright colours like yellow to improve my visibility and keep from getting run down by motorboats.

 

Another option would be bamboo. I made these in about 2 hours. They are ridiculously strong and very lightweight. You cut the blades from 6mm marine ply, cut a slot in the bamboo and wire the blades in place with stainless siezing. Done. Later, I put a pvc collar and turks-head at the oar locks for chafe.

 

Yeah, bamboo is good - for about 3 months. It breaks up and splits when used in water and sun.

 

RW:
Depends on species of bamboo and if preservation is used.

http://www.boatdesign.net/forums/boat-design/bamboo-boats-34249-2.html

Porta

 

The oars in the above photo are now 8 months old and after daily use in salt water with constant exposure to sun and rain they are in great shape and as strong as ever. As Porta notes, proper species choice and cure will ensure long useful life, although my oars are made of uncured poles bought for pennies at a roadside stand in Thailand.

 

Mikereed,

Good to see they are working for you.
Got any hints on making bamboo work well?

BTW, I like my CF ones. Probably not as cheap though.

 

Some bamboo species have a higher strength to weight ratio than CF.

Porta

 

Porta,

"Some" doesn't mean jack.

Got some tests, or "some" names of those fabled species?

I don't believe it. Perhaps I would with some data.
What kind of CF?
What kind of strength measure? Compression, bending, shear, ultimate, 2% deformation, cyclic stress?
Wet or dry bamboo? What % dry?

Or the kind Watson was talking about that cracks after 3 months.

If you want to make such a statement - how about providing something besides un-supported statements. There have been a lot of threads about guys who believed, built something, then reported less than happy results.
Probably due to no information.

I would be happy to review some information (edited out a further challange).

 

Up:

This is but one source that has some info:

http://www.stalkbicycles.com/faq/

I didn't think to question any sources in the detail which you have requested.

Hope this helps.

Porta

 

Porta,

Thanks for the reference.
Nice advertizing copy, but essentially the same unsupported claims.
I certainly understand why you might not have looked for the detail in the claims.

Not going to nitpick, much, but the guys claim that you can drive a truck over a cut section is obviously setting up a special circumstance not applicable to how you use it. Afterall I could lay down a spiral notebook, drive over it carefully and not tear the pages. Presto!, better than whatever you want to compare to. Useless claim also.

I just realized we have had this conversation before - sorry I made you do it again.

 

The best advice I can give on making bamboo work well is to chose the application carefully. They work great as oars and dinghy masts, outstanding as boat poles, flag poles and man-overboard poles, beautifull as interior trim, floors etc.

Also, if you have just spent all winter meticulously building a high-tech rowing shell you don't want to make the oars in an afternoon out of bamboo. However, if like me you just spent 10 days building the dinghy and just want to get on the water then bamboo is ideal. Also, if the oars are going to be used on a tender that will be left unattended on the beach or at a pier all day, then you don't want to spend a week and a lot of money on nice oars that may be gone when you get back after a day ashore.

If you think bamboo is appropriate, then the thicker the wall and shorter the nodes, the stronger and less likely to split it will be. Unfortunately we are usually limited by what is available which may be the thin-walled stuff that splits easily. I was lucky enough to find poles that were meant for construction scaffolding and the smaller ones, around 1" diameter, were essentially solid. I used those for boat poles. My oars are about 1 1/2" dia. with wall thickness about 8mm

If you want to do it right there are several things you can do to increase your chances of having a good, long lasting pole;
1. Chose a culm that is around 3 years old and free of splits and wildlife.
2. Knock out the nodes with thin rebar and soak for 5 days in boric acid soln. This works as a preservative and makes it less attractive to insects. As an alternative, some folks soak the poles for several months in salt water. I soaked mine in salt water for a few days and managed to dislodge some ants and a baby monitor lizard.
3. Allow it to dry slowly in the shade. This can take up to 3 months depending on wall thickness, temp and humidity.
4. I like to use an angle grinder or metal-cutting blade on a chop saw to cut the stuff as these do not tear the fibers and cause splinters.

 

Here's some links to some physical properties of bamboo:

http://www.bambootech.org/files/mechanicaltesting report.pdf
http://www.emissionizero.net/W._Liese_-_The_Structure_of_Bamboo.pdf

Not sure how it stacks up against cf, but I would not use bamboo in place of cf in structural applications on my boat. For a 2 minute dingy mast it rocks.

 

Mike:

Thanks for posting. The first link is quite detailed in the numbers it gives, but I wonder what the verdict is as far as comparing with CF? The tensile figures seem very good, maybe why bamboo was used in Chinese bridges with very long service lives...

But I am not a materials engineer.

I won't repeat advertising claims comparing to CF, if there is no basis...

Porta