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Thread: Rowing Shell stability

  1. #1
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    Default Rowing Shell stability

    What would be the narrowest beam at waterline of a 22' to 26' soft chine strip built single to obtain stationary stability?

  2. #2
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    Default Re: Rowing Shell stability

    Not sure I understand the question as the shells I've known are not stabile if you sit still with oars not touching the water.

  3. #3
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    Default Re: Rowing Shell stability

    Thinking maybe 18 to 22" if seat height is no more than 2" above loaded waterline.

  4. #4
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    Default Re: Rowing Shell stability

    Asking for stability in a rowing shell is like asking for a stable unicycle.

    How much direct experience with long thin boats have you?
    Creationists aren't mad - they're possessed of demons.

  5. #5
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    Default Re: Rowing Shell stability

    Please. If you don't have an answer don't respond.

  6. #6
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    Default Re: Rowing Shell stability

    Hull form is also a significant factor in hull stability. Most shells are pretty close to round-sectioned (most efficient form) which makes them terribly unstable; broader, flatter bottomed with sharper turn of the bilges and shallower draft, like a canoe, is more stable (form stability), but slower. Therefore, the question needs to be asked: are you considering a recreational shell, to be used for exercise and touring about, or do you wish the boat to be competitive? Finally, stability also is a function of the vertical centre of gravity, so the weight and height of the rower is a significant factor. To go to the extreme, women are more stable in a rowing shell than men because of their physiology - women have a lower body CG than men. So, fill me in with a bit more information, and I'll try to help you.
    Hope for the best, but plan for the worst.

  7. #7
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    Default Re: Rowing Shell stability

    Thanks, looked at most of the designs on WB. The Kingfisher looks like a fun build, but basically a racing shell. Would like to find a design for a fast exercise shell that is fun to paddle. CLC has some great stuff, but don't care for stitch and glue. Round bottom would be best for strip plank, but would it track well? Plan on using a sliding rigging set up instead of sliding seat. Would like to be around 55 pounds rigged. 5'9" 170# old guy

  8. #8
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    Default Re: Rowing Shell stability

    Round form will track better than a broad, shallow form. Paddling would be tricky in a narrow hull designed to be rowed. For your purposes, check out the Bangor Packet design (strip cold-mold) or Liz (lapstrake). Both look good, are fast, and are reasonably forgiving. Your weight target is do-able, but challenging.
    Hope for the best, but plan for the worst.

  9. #9
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    Default Re: Rowing Shell stability

    You may find this interesting, Dave Gentry's Ruth. It's even lighter than your specs. Dave's a forum member, and could advise if you wanted something a bit longer and narrower, but I doubt it would be necessary if exercise is the object.

    -Dave

  10. #10
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    Default Re: Rowing Shell stability

    Since I now see that the question is practical rather than academic, I'll weigh in with a few comments from experience. The Bangor Packet is what I would consider a recreational single. It's about the same dimensions as a Maas Aero. It won't dump you if you sneeze like a racing single would, but it's not going to feel stable with the oars out of the water either. Liz is a wherry. To my amateur eye I think her design looks like it would have better initial stability than the Packet but, and perhaps more importantly to a beginner, vastly better secondary stability. You could stop, drop the oars, take off your sweatshirt and have a snack and she will be just fine sitting there as long as you don't do something silly.

    On the question of weight, I think Michael is being optimistic. I'd guess that 60lbs fully rigged would be doable-but-challenging for an amateur builder. 50lbs for cedar strip is going to be very difficult, especially if you want to be able to remove the sliding seat and outriggers so you can paddle (another topic entirely). The problem is that the removable seat and outrigger assembly - for example the Piantedosi row wing - is going to be 20lb-25lb by itself.

    But and however, I don't know that you need to be too concerned about fully-rigged weight if you use a removable seat assembly. To lift the boat, for example to put it on a roof rack, you can remove the drop in seat. Or, as Woxbox suggests, you could build a skin-on-frame boat. I like Ruth a lot. She's on the short list of "boats I would build if I ever get around to building a boat myself".

  11. #11
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    Default Re: Rowing Shell stability

    https://www.duckworks.com/product-p/jm-batto.htm

    I built one. Fast and tippy, but not as tippy as a shell
    Elect a clown expect a circus

  12. #12
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    Default Re: Rowing Shell stability

    For a sliding rigger, strip-built, recreational shell under 55 lbs consider talking to Nick Schade about using his tandem Bootlegger hull form. Tracking can be aided with a thin skeg, such as some have installed on Bangor Packets. He may also suggest his Noank Pulling Boat design/kit.

    https://www.guillemot-kayaks.com/guillemot/node/398/details

    http://www.fyneboatkits.co.uk/kits/r...-pulling-boat/


    Last edited by rbgarr; 06-28-2019 at 02:59 PM.

  13. #13
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    Default Re: Rowing Shell stability

    I paddled a K1 kayak for years, coach would make us stand in a running boat. Did my balance no end of good. Then I had the use of an old planked single, less stable than a K1. A modern single would be less so I'd say.
    I had an option on a single with a crushed stern, thought about rebuilding it with a slipper stern to allow re-entry in deep water. Thought better of it.

    I row my Outred Macgregor canoe, and re-entry into that after a spill is hairy enough!

  14. #14
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    Default Re: Rowing Shell stability

    Not cedar strip, but this boat might be interesting:

    https://angusrowboats.com/pages/oxford-wherry

    http://theoarcruising.blogspot.com/2...r-cruiser.html

    53lbs. From the lines and dimensions I'd expect it to have a decent combination of speed and stability. And it can be paddled, as shown in the post at the second link. It's a bit on the short side for a sliding seat boat but other than that it seems like it would meet the requirements.

  15. #15
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    Default Re: Rowing Shell stability

    I haven't been active on the forum much lately, but I thought I would weigh in briefly on this question, since I have sort of been through the process with boats of this kind, and there is a picture of my version of Gentry's Ruth posted.

    I began 10 years ago wanting to build a strip built hull, and so I began with Nick Schades' MicroBootlegger. I also began a learn-to-row course here at a small local rowing club. Soon I began to imagine mounting a Piantedosi sliding rigger in the MB hull. It took me something like 3 winters to complete the MB, and in the meanwhile I decided to build a Ruth. It went together quickly, and was pretty pleasant on the water, if quite slow and easily blown about compared to a true sliding seat "shell." I found the "removable" rig arrangement kind of a pain though, because getting on and off the water takes a while, mounting and dismounting the rigger.

    After I became a pretty good sliding-seat oarsman, I tried to talk my wife into joining me, and ultimately I built an Annapolis wherry tandem. We use it periodically on summer weekends, and carry it on a Trailex trailer to lakes in the region and throughout the west. Leaving the riggers in, boat on the trailer, and backing it down the boat ramp is a lot less hassle that installing a rigger then pulling it each time you row. It is a nice recreational boat if you aren't in a hurry, and it gets lots of attention from passers-by. But all of these short and relatively beamy sliding seat wherry type boats seem to have features in common that are a bit annoying if you have experience with true rowing shells. One is that the long oar span means that these short boats with quite a bit of rocker relative to true shells demand a very even application of power with each oar or you find yourself zig-zagging along. Another is that both the Ruth and the Annapolis wherry have a relatively high "windage" and both want to head up into a quartering crosswind into the bow. This can mean the need for very unequal application of power to each oar in order to maintain your heading. The virtue is that both are stable, docile, and capable of handling considerably rougher water than a true shell. But being out in those conditions is, for me, usually not much fun either.

    Most of my time on the water now is in true shells at the rowing associations I belong to. I take the Annapolis Tandem out occasionally with my wife on weekends or on vacations in the west, but the MicroBootlegger and the Ruth don't see much action.

    Sliding seat or sliding rigger rowing is a skill that takes some effort to master. Some instruction and coaching can make a big difference--proper form is not intuitive. So ten years in I have learned a few things. One: if rowing is the primary goal, just join a master's rowing club if one is available, and spend more time on the water. Two: if you want to build your own boat, an admirable and worthy goal, you will wind up with fewer boats that get used more if you learn something about what kind of rowing you like and how boats actually behave on the water. Now that I have been in lots of sliding seat boats I still think that there is room for a wherry design that is narrower, longer and consequently faster, and with less rocker for steadier tracking with a wide oarspan. I wish some creative person would design one.

  16. #16
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    Default Re: Rowing Shell stability

    Quote Originally Posted by jackmaggs View Post
    Now that I have been in lots of sliding seat boats I still think that there is room for a wherry design that is narrower, longer and consequently faster, and with less rocker for steadier tracking with a wide oarspan. I wish some creative person would design one.
    My new Racer X, competing in the Seventy48 two days after completion.

  17. #17
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    Default Re: Rowing Shell stability

    Racer X looks great Dave! Any plans or details coming soon?

  18. #18
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    Default

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    Asking for stability in a rowing shell is like asking for a stable unicycle.

    How much direct experience with long thin boats have you?
    🤣 now that you've been properly scolded on an open forum.. stay on topic! Translation = don't say anything else OP doesn't want to hear. 🤣🤣🤣

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    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  19. #19
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    Default

    Most of the rowing shells I have seen hanging in boathouse row buildings and Philadelphia canoe club are very old mahogany veneer, beautiful works of art about as wide as a toothpick.

    Funny, I'm usually pretty good at finding stuff online. For Oxford type rowing shells, I haven't found any strip built yet,

    Stitch and glue seems to be the most popular, skin on frame next,.

    Strip? Too heavy?
    Last edited by DeniseO30; 07-07-2019 at 10:22 AM.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  20. #20
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    Default Re: Rowing Shell stability

    Dave's new skin on frame shells are very interesting. I'd especially like to know more about the double. When will we get more details?

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