PVC Pipe Oar Design

Discussion in 'Boat Design' started by pcfithian, Jan 21, 2013.

  1. pcfithian
    Joined: Sep 2010
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    pcfithian Junior Member

    I plan to build a set of these for a dinghy I've designed, feedback welcome.

    The intent is to make a strong, light, functional set of oars for little $
     

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  2. michael pierzga
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    michael pierzga Senior Member

    Never thought about coring a pvc pipe

    Why not schedule 20 pcv pipe, a layer or two of Eglass unidirection covered by an eglass sleeve, impregnate with epoxy, then wrap with peel ply. Eglass sleeves aren't expensive.
    This is how you home build a carbon dingy mast. The only challenge is keeping the tube straight while curing

    http://[​IMG]
     
  3. pcfithian
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    pcfithian Junior Member

    Good idea on the Schedule 20 pipe, but I haven't been able to find it in 1 1/2" size. I'd use that if I could find it.

    The Schedule 40 pipe is readily available for less than $4 for a 10 foot piece. It weighs ~0.5 lb/ft, so these oars should weigh less than 6 lbs each and be very stiff with the internal X core.
     
  4. michael pierzga
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    michael pierzga Senior Member

    Ive also seen nice tubes made from foam insulation . The foam becomes permanent.

    Might be worth a thought

    http://[​IMG]
     
  5. alan white
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    alan white Senior Member

    Why not real wood? What you describe would be complicated and weak. Spruce is the best choice for light weight. A couple of carefully chosen 2 x 6s would make a superior set of oars. Light, strong, and under ten dollars. I've made lots of oars from 2 x 6s. Good fun and pretty easy to do.
     
  6. upchurchmr
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    upchurchmr Senior Member

    PVC pipe is very poor for an oar.
    An oar needs the best material on the outside.
    Basically the dowel on the inside will take very little of the loading, unless the PVC bends so much that it is only the wood providing stiffness.

    That is what you are going to have here.

    There were discussions on making a paddle shaft using a birds mouth technique. Should be much lighter because it will be stiffer.

    Michael's suggestion about coating the PVC with fiberglass will also be good, especially if you can figgure out how to remove the PVC.

    Good luck
     
  7. peterAustralia
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    peterAustralia Senior Member

    dont do it

    I used pvc for my first pair of oars to get the gap between the rowlock and oar smaller. Did not work, it scratched and deformed and was awful. Use wood.

    My oars were made out of cheap radiata pine covered with epoxy, and laminated plywood blades, work very well. Of couse I used leathers which work well too. Weight is not an issue, it is BALANCE. The weight outboard has to be balanced by weight inboard

    I was able to taper my wooden looms so that with leathers on they fit in the rowlocks and cant fall outboard. I was able to do this because I had a set of oars to copy from and new what width they should be at that spot

    Of all the things that are so-so in my boat, my oars work very well. For high tech go carbon fiber
     
  8. peterAustralia
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    peterAustralia Senior Member

    just a second part, my oar blades were laminated as you have described, but I gave them more curve (I thought they would spring back when the weights were removed) that I had planned, but these quite curved blades worked well.

    The amount of loom you need to support the back of the laminated plywood blades is much less than you have shown, as they are pretty strong.

    The handgrip, THIS IS IMPORTANT - you have shown 1 inch diameter. This is too small. My handgrips are 28.5mm diameter because that was what I could find at the hardware store. I would prefer 32mm diameter. I had to use cloth on my handgrips to avoid blisters ( worked very well)

    I will see what I can do about getting some photos of my oars. I have built 3 pairs now.

    rough weahter oars tend to have longer and narrower blades, smooth water will have shorter and wider blades
     
  9. messabout
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    messabout Senior Member

    An good oar is a living, breathing ,entity that exchanges spirit with the oarsman. Spruce or carefully selected fir will make a friendly and competant oar. Oak or ash is good if the aim is to fight dragons. Plastic is a doable, almost inhuman, alternative and almost a travesty. Wood has soul, plastic is a zombie.
     
  10. peterAustralia
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    peterAustralia Senior Member

    last but not least,,,, my first pair or oars were inspired by the plans that you are using,,, by Michael Storer. They were yuck. Maybe if I had a wherry with 5ft beam they might work, but doubt it. I am the only one I know of who has built michael storer oars ... was not impressed. Also,, the compression loads at the rowlock are massive. It will crush PVC straight away (no doubt)

    give me a day and I will write my an article on building my 3rd set of oars.

    What is the beam of your boat, how long is it. There is a formula somewhere where u put all the dimensions in.

    a very old article i wrote on oars, needs a lot of updating. there are some oar building links on my links page

    http://www.tacking-outrigger.com/oars.html
    note that on these I put the weights in the handgrip, whereas I should have added them externally. Just outboard of the handgrip (did this with my 3rd pair). As to blade width your showing 7.5 inches wide which is 19cm. My oars started off at 19cm ended up now at 11cm wide.
     
  11. alan white
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    alan white Senior Member

    I made a set of 8 1/2 ft oars for my 15 ft sailboat. Although I made them out of 1 1/2" selected 2x stock, they are strong enough and light enough but they balance heavy at the blade end. Oars usually have a thicker (e.g. 2") diameter at the handle end. This is way stronger than needed but why not since the weight has to be added anyway.
    I am going to add lead sleeves just inboard of the grips I think, to balance the oars.
    This puts weight way out on that end so the weight can be less than the larger diameter wood weight compensayion design. The reason is that the wood isn't so concentrated at the end but tapers down the oar evenly.
    I think the best performing oars would have a birdsmouth design of about 2" outside diameter (about a 1/2" wall thickness) all the way and lead inserted inside just short of the grips. Also solid wood at each end and under the leathers.
     
  12. Petros
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    Petros Senior Member

    PVC pipe is a mistake, it has no strength and no stiffness. wood is the lowest cost material with adequate strength, tough and durable.

    If you make composite paddles they will not be durable, and wood has twice the stiffness to weight ratio of fiberglass. the only advantage with fiberglass is it will not rot, but it will break down if left in the sun. Graphite would be lighter, but cost more and much more fragile, likely to get damaged when stored or getting moved around.

    You will not regret a nice wood oar or paddle, I have made many of them and I would now never mess with plastics or fiber glass to make a paddle.
     
  13. pcfithian
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    pcfithian Junior Member

    Agreed, which is why the design uses the X wood stiffener on the inside for the entire 85" length. One plane of the X will be orthogonal to the blade.

    This is an exercise in how to make a set of stiff, light oars with little time or money. It is not a complicated assembly. The PVC will cost ~$4, I can rip the internal X braces in a few minutes on the table saw from leftovers, slot them for half the length on the table saw, fit these together, and slip into the PVC.

    The handles will be larger than 1" diameter, maybe 1.25", after the grip is added as described on the drawing.

    I will also add some lead at the handle end for balance.
     
  14. peterAustralia
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    peterAustralia Senior Member

    when you put pvc in the rowlock it scratches and does not work well, been there done that

    If you want to experiment and see how it goes, then fair enough, just maybe have a backup option, my wood oars did not cost much, just cheap radiata pine, some plywood, a bit of dowel, and a little epoxy
     

  15. michael pierzga
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    michael pierzga Senior Member

    Ive always made oars from wood. It takes many , many hours to produce a nice pair ...then many ,many hours to varnish them. If I sold you a pair ,your wallet would hurt

    Fiberglass tubes might be worth a try.

    Perhaps have a look at a pair of competition oars to see if there are any detail tricks to learn

    http://[​IMG]
     
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