designing a fast rowboat

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

  1. NoEyeDeer
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    NoEyeDeer Senior Member

    He doesn't use sleeves on his oars. ;)
     
  2. Clinton B Chase
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    Clinton B Chase Senior Member

    I'll probably go with the Sarana's.

    I look forward to sharing the current project. Working on a midship section to the new boat.

    This weekend I see Drake off to a new home.

    I may do little rowing this year.
     
  3. NoEyeDeer
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    NoEyeDeer Senior Member

    Will be interested to see what you come up with. I've done SFA on mine. Too busy with other stuff, but should have another crack at it soon.

    I was thinking about the Sarana's. They're nifty, but having the pin pivoting athwartships like it does is going to mean a large change in blade pitch between the beginning and end of the stroke. Obviously this doesn't seem to bother them too much in practice, but it's not ideal by any means.

    In terms of pitch control, it would actually make more sense to have a simple fixed pin, with the bushed hole in the loom elongated to allow the right vertical range of movement. This would also be simpler, cheaper and lighter than the current arrangement.
     
  4. Clinton B Chase
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    Clinton B Chase Senior Member

    One day I want pinned locks, the next I want traditional horned locks with leathers, the next I want feathering....8 foot oars, or 9 or 8 1/2...another I want a double ender, the next I want a full transom, the next I want a high tucked up transom.

    This is going to be a long process.

    Here are some stretchers I made recently. Follow the link for more.

    [​IMG]
    Rowing Stretcher by Clint Chase Boatbuilder, on Flickr

    Late night query.

    As I mock up my rowing station, I am thinking about tranosm vs no transom vs skinny transom. We're been talking about resistance a lot, and it has come up that it changes with trim. Well, in a rowing stroke, trim is changing stern down as we move into the catch and bow down as we pull into the finish. So, it would be worth looking at resistance through the stroke and I would set the resistance to be lowest for the catch part of the stroke. I am really thinking a double ended waterline would be best. I have a hell of a reach...my locks are 15" aft of seat...I can really push the stern down in the catch.

    I am also thinking about seaworthiness and think a high, skinny transom would provide the double ended waterline and lots of reserve buoyancy for any waves that want to try to "board" the boat.
     
    Last edited: May 25, 2013
  5. NoEyeDeer
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    NoEyeDeer Senior Member

    If you want to get into that level of detail, talk to Leo. He's done it for racing shells and it gets very complex if you want the results to mean anything.
     
  6. acp1934
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    acp1934 Junior Member

    I have been having similar thoughts. I'm finishing up a slightly hot-rodded stretched Bolger light dory for my son and I, to replace a boat I sold, but thinking about a single for myself. I'm somewhat set on a Culler Otter style Bateau, but plumb-sterned, with a transom above the W/L, maybe like the Duck Punt is done, but then I think maybe with a V-bottom, for a finer entry while still being pretty full in the bow, since all boats involve compromises, it's tough to decide which way to go.

    If a stern was double ended fine at the W/L, but flared out just above, I think it would help out in sprint mode, when the stern drops, but I guess it would only be practical on flat water, which is in short supply here, except early in the AM, in rougher water I guess it would add drag, probably better to start the flare higher.
     
  7. nordvindcrew
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    nordvindcrew Senior Member

    Blackburn

    Just to try to clarify, the start is just north of the railroad bridge. When I scaled it out, I came up with almost 21 statute miles. I was scaling off of a road map book so not too sure if the map was accurate. 12 years ago, I did the blackburn in a 19' Jersy skiff rowing double. She was big, wide and heavy. We finished in 3:48 and change if my memory is correct. That was good enough for third in fixed seat doubles. A fishing boat that cut in front of us cost second place, but oh well. Just a couple of random thoughts. Clint, yuo're a huge guy, so you have a strong mechanical advantage. Way back in this thread, someone wrote that their three things to worry about in a rowing boat: the motor, the motor, and the motor. The best boat is only as good as the condition and level of training as the man at the oars. When I was winning races, it wasn't because I had the fastest boat, it was because We were in good shape and willing to hurt ourselves more than others. That is true today. One thing you may not be considering is rowing style. I've watched Paul Neil row, and couldn't row that way if my life depended on it. He sits bolt upright and does all the work with his arms. My brother and I reffered to him as "the hummingbird" because his cadence was so fast. One guy we race against went from a Gloucester Gull to a guide boat. It took him over two years to adapt his style to the boat. Jon Aborn and his Monument River Wherry are always the single to beat around here, and he is willing to give away his plans for the boat. I couldn't row it either. Jon sits almost on the floorboards which would cripple me. Clint, Drake is a real nice boat, and you've learned to make her go fast. If you go to along narrow design, your rowing style will not transfer to it. Every new boat my brother and I have built has taken ages to sort out and learn how to row it at the fastest possible speed.
     
  8. acp1934
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    acp1934 Junior Member

    That is another very good, yet complicating thing to think about, Nordvindcrew, matching the boat to your particular style.
    It's good to see you posting here again, this thread you started has been a favorite of mine for years, thanks for that!
     
  9. Clinton B Chase
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    Clinton B Chase Senior Member

    Absolutely to the last two comments RE: rowing style and matching oarsman to boat appropriately. I is so much easier doing this for others, now I need to do the same for me again.

    To Jeff's comment, Drake fits me great, but I want a boat designed for more turn of speed and efficiency for open water racing but, you are right, I have to make sure it fits my style. SO, I am spending some time mocking up a midship station in CAD and in the shop. I will post some updates.

    The two main improvements over Drake will be to have a hull much lower resistance than Drake yet have enough spread to carry long oars-on-gunwale. If I try to have 9' oars then I'll have a far out hull. Much like the section posted a while back. So, I have to settle on the longest oars possible with some hand overlap but not too much...probably 4" or so max (one hand overlap). Right now I think any shorter than 8 1/2' and my rowing style will definitely be crimped! This hand overlap requires a different seat height relative to oarlocks so the pull is more towards the belly than chest and one hand can lead the other in the overlapped pull. With the moderate overlap it feels more efficient and when I have rowed this way it feels OK so long as the oars are still decent length. But it all needs to be mocked up so that I know I fit the picture biomechanically/ergonomically. The new boat will demand a different stroke, but nothing too wild and it will fit me otherwise I won't do it.

    It will be another learning experience as Drake was and continues to be. I hope to get back to work on some outriggers for Drake that allow the oars to be mounted oar-on-gunwale for races (the outriggers fold in). I'll also do some tweaks to Drake's hull to make sure she is most up to date, but the changes are fractional.

    I'll have two different boats in the end and it will be cool to see what I go to most.
     
  10. Clinton B Chase
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    Clinton B Chase Senior Member

    Working on a rowing station for me. Will make the boat around it. (Can't see in the pic: oarlocks mounted on sawhorse.)

    [​IMG]
    Rowing Station Mock-Up by Clint Chase Boatbuilder, on Flickr

    The key here is getting oarlock height, seat height, etc all to the right proportions. I have found that you can get surprisingly close doing this mock up.
     
  11. ancient kayaker
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    ancient kayaker aka Terry Haines

    A thought: should the feet and seat should be raised by the width of an oar blade so you can try the full rowing motion?
     
  12. Clinton B Chase
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    Clinton B Chase Senior Member

    Added pads under feet to represent height in boat.

    [​IMG]
    Mocking Up a Rowing Station by Clint Chase Boatbuilder, on Flickr

    Oar stick drags on floor...so height of hands is actual.

    [​IMG]
    Mocking Up a Rowing Station by Clint Chase Boatbuilder, on Flickr

    Nice centerline (pads under feet not in this shot)
    [​IMG]
    Mocking Up a Rowing Station by Clint Chase Boatbuilder, on Flickr

    Actual oarlocks used and placed. All measurements were well within 1/8" of the CAD drawing.

    [​IMG]
    Mocking Up a Rowing Station by Clint Chase Boatbuilder, on Flickr

    Here is my rowing station, with the hull and fgunwales drawn to what I think the boat will look like.

    [​IMG]
    MockingUp.1 by Clint Chase Boatbuilder, on Flickr
     
  13. Jon A
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    Jon A Junior Member

    Greetings All,
    Just registered for this forum after Jeff told me about it yesterday. I have skimmed thru some of the posts on this thread and it's certainly good to see people thinking about fast pulling boats. If you'll allow me to add a few random thoughts:

    The guideboats have such a good reputation because they have been rowed by some tremendous athletes. Paul Neil and Gerhard Munger come down from upstate NY where the training and racing is intense and their big race is 90 miles with a few portages thrown in. These guys could make a flower box go fast. Guideboats are great boats but they are fishing boats and their oars are fishing oars, pinned so you can let go and fish. Paul's boat is light, maybe 60 lbs, and I think that is a big factor in it's speed.

    But, whatever the reason, in all fairness, the guideboats have set times for the Blackburn that will be very hard to beat. You have to respect that.

    The Monument River Wherry that I built and now row is an improved version of the one Walter Baron built for me 20 years ago. It is very fast, easy to row, a little wet and pounds a little to windward in rough conditions and it weighs about 100 lbs. Construction is 4mm and 6mm plywood, simple and quick to build. Both boats were built from scale half-models that I carved after rowing and racing in many boats, an old fashion technique but it worked for me and I enjoyed the process. I am considering building a third version next winter with maybe 3 planks to a side instead of the present two to get a little better, more refined shape and a target weight of less than 80 lbs. It's fun to think about.

    Finally, any boat built to compete in the Blackburn or to be used on open water should have enough buoyancy in the right places to support the rower and provide a chance of self rescue. It's only fair to everyone else out there.

    Good luck to everyone, I look forward to seeing a bunch of new, fast boats at the races.

    Jon
     
  14. keith66
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    keith66 Senior Member

    Im liking the way Clint has mocked up his rowing station & is designing the boat round it. All the rowboats i have built have had their rowing positions mocked up in the hull, normally sitting on a wooden block, bucket or similar.
    With Clints height he would be awesome in a sliding rigger boat.
    What is said about Crews is spot on though, my old club has a beast of a mens crew & they train very very hard, The Gig they use is relatively light & its a hard combination to beat.
    Im building a Gig at the moment, she is 27ft x 4ft 6" beam & is to be built in GRP foam sandwich, Jigs finished & the foam core starts going on this week.
    Heres a shot from above taken a week ago, more info on the story on my blog, http://eastcoastrowing.blogspot.co.uk/ ,
     

    Attached Files:


  15. Clinton B Chase
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    Clinton B Chase Senior Member

    Jon I hope you continue to check out what we talk about from time to time. There is a lot of good info and a nice mix of on-the-water knowledge and theory.

    Keith, that looks like a great project. I checked out your blog (there is no "follow this blog" thing to click on it???). I would be good on a slide if it were not for a not-so-good left hip! I even feel it after a long fixed seat row.

    I hear what Jon is saying, but it seems that the GB is purpose designed and built for the inland lakes and rivers. A boat that was purpose designed for doing coastal races like the Essex and Blackburn would make a big splash. I'll leave it at that!
     
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