Women's Light Weight Scull Design Help

Discussion in 'Boat Design' started by arumz, Aug 18, 2015.

  1. arumz
    Joined: Aug 2015
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    Location: Texas

    arumz New Member

    I am finally taking the leap and starting to design and build my own scull...Ive seen the usual suggestions King Fisher, Uffa Fox, CLC etc.

    My biggest problem is I need a lightweight boat (<130lbs, 5ft 9inches).

    Ive had several years of experience competing while rowing sweep so transitioning to sculling does pose stability concerns but by training on other elite boats Im not too concerned with being able to pick it up with practice.

    I want to be able to compete to come degree with the boat I build at least at the club level.

    Right now Im having trouble deciding the overall dimensions of the boat that will best suit my frame. The arguments of short versus long hull and beam width have left me turning to you for suggestions. Thoughts anyone?
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    Designing a reasonably competitive scull, without the theory understanding will be very difficult. This isn't to say you couldn't develop a shape that floats, preferably with the slides facing up, goes pretty good, etc., but is to say, even at the club level, you'll need a pretty fine point on the physics and engineering.

    There are a number of relatively recent startups, focusing on small, human powered craft, many SOF, but some in more solid materials. I mention these because they'll have a pretty good idea of efficiency and light weight, for this size boat and picking their brain for an hour on the phone, could save you lots of headaches down the road.

    Contact Kudzu at messing-about.com. Tell him PAR sent you and lay out what you're looking to do, your experience, skill sets, etc. If he baulks, drop me an email (click on my icon) and I'll see what I can find for you.
  3. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    You are right that the Stability Thing shouldn't worry you.

    I took a grand total of 1/2 of my scheduled 2 one hour sessions of instruction and never looked back with a well used Maas Vancover(Areo with tall rim). And I was a top heavy 270lbs just over the rated limit for the boat.

    Its like a bike, but different. It ALL comes from the oars, so don't think you need a wider hull for stability as a beginning sculler.

    Any advertised "more stable wider hull" on a rowing shell is for when you aren't actively rowing IMO.

    Maybe a slightly wide hull could be helpful for the first 1/2 hour when you are still getting a feel for using both oars to balance, just so you aren't wasting time re-boarding after spills. The couple times I took my shell out BEFORE my one lesson I couldn't get it going AT ALL, and only managed to amuse some onlookers.

    Expect to keep banging a bruise on your right knee on the recovery stroke until you learn not to (all shells are set up with right oar under left when overlapping).

    Once you get going, you don't steer with conscious adjustment of arms on oars, you steer by adjusting foot PRESSURE on the power stroke while rowing normally.

    Not sure if its same for sweep rowing, but when sculling I paid lots of attention to the wake and oar swirls I was leaving behind to hone my technique. Looking at where I'd been became more interesting that where I was going.

    I never got too deep into the sport, just rowing for fun on lakes and sloughs, but if building a custom boat for a smaller framed person be aware there is lots of Proper Fitting to be done to be competitive, and IIRC most serious competitive rowers tend to be tall and lanky.

    One place I called about beginner lessons wouldn't touch me unless I'd sign up for months of lessons for thousands of dollars and tried to tell me I'd have no chance with anything less.

    I couldn't imagine WANTING to crew on a multi-oar boat with some little dweeb nasally squawking "stroke, stroke, stroke" at me. Maybe a drum beat such as for galley slaves in an old Sword & Sandal movie, or something with some funk.
  4. philSweet
    Joined: May 2008
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    philSweet Senior Member

    Unless you are sponsored, the way most manage this is through an apprenticeship program at a small builder. Basically, they let you build one for yourself as you work there. Can you take six months off and do that?

    With luck, Leo will show up. He has some pretty exclusive knowledge of elite rowing ergonomics. He wrote a program to analyze Olympic rowing technique and predict performance. The program is available from his website Cyberiad.

    linky - http://www.cyberiad.net/firm/firm.htm
  5. messabout
    Joined: Jan 2006
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    messabout Senior Member

    Arumz you have fallen into a pot of jam. There are some exceptionally knowledgeable people here, most of whom are generous. Among them is previously mentioned, Leo, who is a world class authority on such stuff as sculling boats. There are others too who are well informed about human powered boats.

    Hang around for a while before you begin to do design work. There are some delicate nuances for such a boat. Might as well get it as close to right as you can before you start to build.

    If you anticipate competing at the club level or beyond, then tell us what the limitations are that will accord with whatever the rules might be.
  6. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    When I used to build sculls, we had different size boats to suit the rowers weight. However the length of the shell only varied by a couple of centimeters at most between say a 55-65Kg scull and a 100-110Kg one. These were and are pretty quick boats even today, so go with a decent length, it's part of the speed for a number of reasons.

    I'd suggest trying as many shapes that are already around as you can. It should inform your direction of thought and the shape you would prefer. Like any other boat, you need to get a feel for the 'run' of the hull through the water. Lots of other stuff like riggers, blades etc can be changed but the hull behaviour is a lot more fixed.
  7. arumz
    Joined: Aug 2015
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    arumz New Member

    Thank you all for your replies....

    PAR I reached out to Kudzu and hope to hear back from him soon to get his perspective.

    I am in the process of trying out several different styles of single sculls. This weekend I have plans to spend Saturday testing the waters with an experienced sculler from the boat house I belong to.

    I wish I could take 6 months off to learn the trade but as most of us probably find that is hard to do!

    Ive been looking into using DELFTship to help in my endeavors.

    Is my best option to find a boat that suits me and backwards engineer it?
  8. Leo Lazauskas
    Joined: Jan 2002
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    Leo Lazauskas Senior Member

    If you will be trialling a number of different shells I strongly advise
    you to try one of Sykes Racing's lightweight shells.

    The North American site is at:
    http://www.sykesna.com/singles.html (That page should be
    updated soon. The shell is now available for sale.)

    DISCLAIMER: I did not design the shell, but I did assess the drag and
    stability. The Mould 35 has been very successful after some excellent,
    very recent performances here in Australia.

    It is a splendid idea to try to design your own boat but, unless you are
    prepared to spend several years learning the art, craft and science of
    hull design, you don't have an icecream's hope in hell of doing better
    than the many very experienced rowing shell builders around the world.
    PAR's friend would be a very valuable contact for you.

    Another disclaimer. While I know a lot about the hydrodynamics of rowing
    shells, I would never try to design and build a hull myself because
    there is so much more to the process than simply coming up with a
    satisfactory shape that ticks all the boxes. I know next to nothing about
    materials engineering, nor do I have the practical skills to judge
    whether a shape I come up with is actually realizable. Do you? :)

    Good luck!

  9. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I agree with Leo, there's a fair bit to a number of disciplines, which go into even a reasonable design, let alone one that will prove moderately competitive. FWIW, reverse engineering is much more difficult than just designing from a solid SOR and a blank screen.

    Basically you need to ask yourself about your capabilities. How well do you think you can engineer a structure, that's light, stiff and strong enough for the SOR goals, while refining this to be as efficient as practical, in the range and performance envelop you're targeting. I'm sure you could develop something that'll float, look and feel like a shell, but will this be sufficient, or do you really want a reasonably competitive shell, at the level you plan on playing and do you have the understanding (or are willing to learn) to model this set of variables?
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