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Birchbark & Laminar Flow

Discussion in 'Birchbarks, Dugouts and Primitive Craft' started by slidegear, Apr 1, 2013.

  1. slidegear

    slidegear Alan Sidlo by default

    Anybody else out there notice just how well the natural hulls move through the water? I could be wrong but my take on the matter is the slight imperfections and the fact that the surface tends to hold liquid close to them provides a layered effect as the vessel moves through the water. I've only done a preliminary search but nowhere have I found this mentioned so far. I may be way off base here but my gut feeling is it's because of laminar flow.
     
  2. Dan Miller

    Dan Miller cranky canoeist Staff Member

    Protuberances, like the rivets on a Grumman, or the pitched seams on a bark canoe, disrupt laminar flow and increase drag. The least drag is found on the smoothest hulls. That is why canoe racers insist on having their hulls not only as fair as possible, but also as scratch-free as possible.

    Your perception of going faster is probably enhanced by paddling something that is otherwise highly pleasurable.

    For a full treatise on this and more about canoe design, I refer folks to John Winters's "The Shape of the Canoe" which is available here: http://www.greenval.com/TheShapeOfTheCanoe.html
     
  3. beaver

    beaver Birchbark CanoeingBuilder

    Excerpt from "The Travel Journals of Tappan Adney 1887-1890" ~~Canoe Races at Woodstock ~~ ""We did not fear any of the other barks, but we were dubious about the Green Diamond, as she was called, the smooth painted canvas canoe, for the smoothest birchbark is not so smooth as painted canvas though we had given Pocohontas a good coat of shellac, and she glistened in the sun.""
     

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