designing a fast rowboat

Discussion in 'Boat Design' started by nordvindcrew, Oct 13, 2006.

  1. terhohalme
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    Can't beat the olympic shells :D

    The big question is, should the boat be stable or unstable at rest. If the boat need to be stable without activity by the rower, the Finnish rowboats are near the limit. My boat's GM with two rower is about 8 cm.

    More stability means wider waterline, more wetted surface, more drag...
     
  2. terhohalme
    Joined: Jun 2003
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    Sorry, just the rule.

    Here is some older information: http://koti.kapsi.fi/hvartial/scull/scull.htm

    My newest double version:
     

    Attached Files:

  3. NoEyeDeer
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    NoEyeDeer Senior Member

    Must admit I was thinking more of singles when I commented, and with the lower immersed volume a single could stand quite a reduction in BWL without GM going negative.
     
  4. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    That's a lot of interesting info from Kotka,
    but what's the cox drinking?

    [​IMG]
     
  5. terhohalme
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    terhohalme BEng Boat Technology

    No idea, where Hannu is living...

    Also the rules are updated, now normal rolling bench is allowed. Couldn't find the new rules in English.
     
  6. ancient kayaker
    Joined: Aug 2006
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    ancient kayaker aka Terry Haines

    Nice looking boats. The designs of modern canoes and fast rowboats seem to be converging, with fine entry, vertical stems, maximum beam well aft and only a nominal transom, very light construction with just a few slimmed-down frames. Not sure how the waterlines would compare underwater, but I suspect the main difference would show up above the water.
     
  7. nordvindcrew
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    nordvindcrew Senior Member

    beverage

    We consume Aquavit (homemade) after a race, perhaps the Finns also have this tradition.
     
  8. nordvindcrew
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    nordvindcrew Senior Member

    progress

    The Nordfiord is back together. All old structure is gone and final work to re-inforce the connections of old to new will be done this weekend. Right now, with no internal structure, everything is pretty flexible. With thwarts and decks, the rigidity will come back and the hull will be stable. She's going to be very tippy untill we get seated, but should firm up well at that point. I won't be able to get her in the water before the race but, I think, it will be ready for the 23thd. The law of unintended consequences came into play. With no intention at all, the hull came out looking very much like a Swampscott Dory. In fact, when asked to identify it for a race, That's what I'm going to say. Might get me in the work boat class instead of livery class.
     
  9. JotM
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    JotM Junior Member

    Yes you can. And, as Nordvindcrew pointed out, it is done in Jersey skiffs used in Jersey Shore Rowing.
    Although judging from images I don't think they all have foot wells.
    (there are some great pictures in the album "2008 ASBURY PARK LIFEGUARD CHALLENGE" by Andrew Mills)
     
  10. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Olympic class single shells have a GMT that is about 28cm above the undisturbed waterplane. Wider, more stable shells, are used for beginners.

    Leo.
     
  11. nordvindcrew
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    nordvindcrew Senior Member

    open stern

    Those Jersey skiffs with no foot wells look like the rowing position is pretty terrible to me. A few years ago, one showed up at the Snow Row. It looked like a good boat, but the seating was awful. The guy could hardly row it. His oars were too high and his feet were almost elevated. Maybe some have better ergonomics than that one . Nordfiord won't be ready for this weekend: still have to build the decks then glass them in. Just not enough time when I get home from work. I spent all last wekend working on her but glassing the inside seams took a ton of time: hours of grinding to fair things up then very tedious work to get the mat and cloth in place.
     
  12. keith66
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    keith66 Senior Member

    It looks to me like those Jersey Skiffs use a similar sliding type seat to the Aussie surf boats, otherwise they are going to be uncomfortable to row, great action shots though!
     
  13. terhohalme
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    terhohalme BEng Boat Technology

    With the rower?
     
  14. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Yes, my figure included the big ox who rows the boat :)
     

  15. terhohalme
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    terhohalme BEng Boat Technology

    Ok, I figure the gravity of Savonian 1 ft (254 mm) above the seat.

    ps. Savonian is a man from Savo province, usually light and durable, but when he talks the responsibility is on the listener's side...
     
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