designing a fast rowboat

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

  1. Leo Lazauskas
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    Leo Lazauskas Senior Member

    It's not relevant to coastal racing is it?
    I suspect that there is no testing for performance enhancing drugs either.
    So, by all means, fit sliding riggers and find a good dealer :)
     
  2. keith66
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    keith66 Senior Member

    The ban would apply to the Coastal rowing boats governing Associations otherwise they might well have used them by now, i can also see British rowing getting hot under the collar if an affilated club started racing sliding rigger boats. In the end though they can not actually stop us using them. Perhaps its about time we did!
     
  3. DCockey
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    DCockey Senior Member

    In the US at least FISA does not have any authority outside its members and those under them. Anyone else may organize a race for boats with sliding riggers. Or a race for boats without sliding seats.

    Now the FISA rule banning sliding riggers. FISA Rule 1, second paragraph:
    In a rowing boat, all load bearing parts including the axes of moving parts, must be firmly fixed to the body of the boat, but the rower's seat may move along the axis of the boat. ​

    So it appears that this rule allows sliding seats with no provisions for race rules requiring boats with fixed seats.
     
  4. keith66
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    keith66 Senior Member

    Righto, so you want a sliding rigger unit, its prohibitively expensive to import a piantedosi unit to the uk. There is a very similar unit made by Schroeder rowing services in Germany. The poseidon twin rail sliding seat unit made by Puuvenepistte would seem a good basis for one as well.
    As far as a sweep sliding rigger unit goes i have searched & found nothing.
    The asymetric stress of a sweep oar would seem to cause problems but then i thought what if the rowers seats were staggered? One rigger unit rail could be mounted low down near the bottom of the boat near the centre line or bilge stringer the outer rail just below the sheer either at seat riser or just below gunwale height.
    foot rest mounted between the two. Hard bit would be keeping it light enough!
     
  5. DCockey
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    DCockey Senior Member

  6. nordvindcrew
    Joined: Sep 2006
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    Location: Marshfield massachusetts usa

    nordvindcrew Senior Member

    old guys

    Keith, great report on your race. I love your description of holding off a challenging boat. Over here, often times, how you start is how you finish. we worked our rear ends off over at least a mile to pass one boat as we got near the finish line. Put the pass on and pulled away by a couple of hundred yards in the last mile. It's always tough going in a situation like that. I know about old injuries; they reoccur it the worst times. Keep at it, and keep us posted on races from your side of the pond





    I
     
  7. Clinton B Chase
    Joined: Mar 2005
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    Clinton B Chase Senior Member

    How you start is also how you don't finish. I learned while bike racing that starting in a sprint is certainly going to kill the energy by the end. I like to start easy and watch the others work really hard while I casually pull and stay with them. Kinda mean, but fun too.
     
  8. SailorDon
    Joined: Apr 2013
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    Location: Livingston, TX

    SailorDon Senior Member

    Fore-Aft Weight Distribution in Thames Rowing Skiff

    I'm new to the sport of performance recreational rowing, so I ask a lot of rowing type questions.

    The builder of my Mandarin 17 suggests that I need more ballast in the stern for better performance.

    I'm thinking that when the bow comes out of the water, which effectively reduces the waterline length, the wave making resistance and the turbulence of pounding slow the boat down.

    Here are two examples from screen captures showing a lot of bow out of the water from yesterday's rowing exercise.

    [​IMG]

    [​IMG]

     
    Last edited: Aug 19, 2013
  9. Jon A
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    Jon A Junior Member

    Nice looking boat.
    What does it look like with you sitting in the boat in calm water? Is it down by the stern or bow? In my simple mind you want the bottom to run parallel to the top of the water to be efficient. Pounding into a sea is a function of shape and I am not sure how much ballast will help.
    Also, I would judge weight distribution on the boat's ability in a following sea. You don't want the bow diving into the wave in front of you and causing a broach.
    Finally, it would be better to shift the rowing position fore or aft to achieve proper balance. Why go to the extra effort of hauling around a bag of rocks.
    Thought I saw a little porposing in one of your passes where the bow dives as you lay your weight forward on your stroke. But you would also see that in calm water if that was a problem.
    Hope this helps,
    Jon
     
  10. SailorDon
    Joined: Apr 2013
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    SailorDon Senior Member

    Jon,

    Thank you for your reply, complements, and comments. They all help. :)

    As far as the "nice looking boat", the complements should go to the designer, Selway-Fisher, and the boat builder, PicnikYachts (Paul Kirwin), Sugarland, TX.

    The best information I have for calm water rowing is from this morning's rowing exercise.

    Performance Summary:
    [​IMG]

    Photo:
    [​IMG]

    Video:

     
  11. El_Guero

    El_Guero Previous Member

    Move your seat 1.72 feet towards the stern.

    Why cary extra ballast, when your body weight should be more than enough ballast?
     
  12. SailorDon
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    Location: Livingston, TX

    SailorDon Senior Member

    I agree with moving the seat aft instead of carrying extra ballast. It is not an easy adjustment since this is a fixed seat design.

    How do you come up with the 1.72 feet adjustment factor?
    .
     
  13. El_Guero

    El_Guero Previous Member

    Well, I started with the length of the boat compared to the length of the lake and ....

    Just pulling your leg. You will need to experiment to get the right position. But, rather than move the seat, put in a folding seat.

    Even a camp stool would work, wouldn't it? Use bungie cords to secure it so you don't fall of it to easily.

    In fact, just butting a second seat up to the current seat might give you enough weight to the rear for what you want. You do not want too much, or you will always be "rowing uphill" .....
     
  14. Jon A
    Joined: Jun 2013
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    Jon A Junior Member

    Assuming you have removed the ballast in the new video, maybe you could move just a little further aft, a few inches. It looks like the oarlocks are far enough back so maybe they can stay. On my boat the center of the oarlock is about 11 1/2" behind the edge of the seat.
    Once on a calm day I bailed a couple of gallons of water into one of my boats and sat in it very still and observed the location of the puddle under me. The puddle seemed to mirror what I wanted for a waterline on the outside and seemed to confirm that I had the rowing position about right. It did confirm to my wife that I was hopelessly over the edge.
    Those oar leathers look to be wearing badly. Many recommend tallow, I use Vaseline to lubricate.
    Do you need the rudder? From the looks of the boat it may not be necessary.
    Hope this helps,
    Jon
     

  15. EirikNorway
    Joined: May 2012
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    Location: Norway, Oslo

    EirikNorway Junior Member

    rowboat

    Hi im working on a rowbot WiTh a sliding seat rigger. Length 5000 beam 900(600at waterlevel) weight 500.
    Fine entry and exit. My next iteration Will have a finer exit, hence making It faste, but not a good surfing boat and not able to carry that much weight aft. Any comments on the design. Inspired by whitehall etc

    http://m.flickr.com/#/photos/7682263@N02/sets/72157635216754530/

    Eirik
     
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