front rowing system for canoe

Discussion in 'Boat Design' started by jyoder111, May 3, 2011.

  1. Jeremy Harris
    Joined: Jun 2009
    Posts: 978
    Likes: 60, Points: 28, Legacy Rep: 711
    Location: Salisbury, UK

    Jeremy Harris Senior Member

    I'm using oilite top hat bushes, two off on each pivot, 10mm ID, 13mm OD and 20mm long, so a total bearing length on each pivot of 40mm, running on a 10mm diameter stainless pin. These bushes also take the axial load on the thrust face of the lower bearing at each pivot.

    The linkage bearings that I'm using are 10mm stainless steel male rod ends, with Teflon inserts. I chose these because I didn't want to have to worry about alignment problems to make the whole thing run freely. I just need to machine up a few more parts and my unit will be ready to test.

    Jeremy
     
  2. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Squidly: I've gone back to your curved channel concept in this sketch, but I have replaced the curved channel with 2 straight ones. In addition to simplifying construction by eliminatng the need to bend the channel, it has straightened the handle path considerably. Compared with the linkage concept, the geometry is much easier to solve.
     

    Attached Files:

  3. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,957
    Likes: 176, Points: 63, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    AK, another "stroke" of genius!

    Those would also allow for easy and instant adjustment. Each track would have an Inside and Outside mounting point to grab the gunnels(or the hull just under the gunnels) and the angle of the tracks would be determined by sliding the mounts on the tracks.

    I think one set(2x2) of such tracks could be adjusted to accommodate either long or short oars and fixed or sliding seat.

    That is 2x the mounting points of a curved track but more than worth it(C-clamps are dirt cheap). Straight track system would be 10X cheaper/easier to fabricate than curved, and probably 10X as jam resistant.

    I like the gunnel mounted tracks because it allows the oars to be dipped as normal(with up/down only pivot on the "T"), and seems cleaner without sets of arms flopping about either in or out side the boat.

    Outside trapezoid arms would required some sort of support, which would be doable but not ideal.

    I'm still very confident that with the loads we are talking about(one puny human's arm strength, and not even a "max effort") that the bearing loads wont be a problem and even semi-soft wheels(from skates) would work fine.


    I was having some safety concerns with outrigger trapz-arm rigs, as I could imagine getting tangled up in all those moving arms during capsize. I could imagine getting entangled with the oar and outriggers in a Maas Aero but I guess it doesn't happen too often....but a lot of thin metal tubes which I think would want to swing against the hull during a capsize, but still have lots of openings to ensnare body parts while doing so, on an un-vetted contraption, worries me.
     
    Last edited: May 28, 2011
  4. NoEyeDeer
    Joined: Jun 2010
    Posts: 983
    Likes: 32, Points: 28, Legacy Rep: 300
    Location: Australia

    NoEyeDeer Senior Member

    Question: if you're going to go to all this trouble how about hooking up your feet too? Lotsa extra power there.
     
  5. upchurchmr
    Joined: Feb 2011
    Posts: 3,287
    Likes: 259, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Gents,

    Perhaps I missed a discussion, but how much force is it going to take to lift the blade out of the water on the recovery? It seems like everyone wants the "pivot" or track close to the side of the boat and short handles. That should increase the hand force to recover. Hope you all have carbon fiber oars.

    The two straight tracks is clever. Straight or curved I'm waiting to see how you prevent rotation of the carriage (wheeled mechanism) around a fore and aft axis.

    Marc
     
  6. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Personally, I’m not interested in performance, I hope rowing will prove less stressful than paddling and facing forward will help avoid all the obstructions where I go boating.

    A present, the answer is, far too much, but this is early days.

    I think the carriage can have a simple a cam follower at each end, with a slightly rounded roller profile, which I think is a standard option. This will permit the carriage to rotate about the X axis to allow the oar to be raised for the recovery stroke.

    The biggest worry I have at present is the length of the various elements.
     
  7. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Incidentally, if the channels flipped and attached to the oars, running over 2 rollers on the gunnels, it becomes a kind of virtual outrigger, although it's not a front rower this time. That could put the cat among the pigeons in rowing classes where outriggers are banned . . . I think I will go to hell for this one!
     

    Attached Files:

  8. NoEyeDeer
    Joined: Jun 2010
    Posts: 983
    Likes: 32, Points: 28, Legacy Rep: 300
    Location: Australia

    NoEyeDeer Senior Member

    Now that's rather cunning. :D
     
  9. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    You people are leading me astray . . .
     
  10. Jeremy Harris
    Joined: Jun 2009
    Posts: 978
    Likes: 60, Points: 28, Legacy Rep: 711
    Location: Salisbury, UK

    Jeremy Harris Senior Member

  11. upchurchmr
    Joined: Feb 2011
    Posts: 3,287
    Likes: 259, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Look like Kawai Kazuaki has done all the development for us. Wish I retained what little Japanese I had once.

    My question about preventing rotation of the mechanical carriage seems pretty silly now. Using a bent tube allowed the oar to be dipped without a separate special pivot. The tube gets my vote.

    I'm still pretty sure the skateboard or roller blade wheels will work poorly.

    To me the only unanswered question is what is the proper radius for the track, especially if I put one of these on my wifes boats - or maybe mine. Looks like 8 wheels on a 1" dia bent tube. Now if I want to use a sliding seat (or feet) would I use a simple arc for the bent tube, just longer?

    Thanks for the Japanese website. I had seen this before but could not make out what was happening in the first video.

    Marc
     
  12. magnus
    Joined: Mar 2010
    Posts: 72
    Likes: 2, Points: 8, Legacy Rep: 37
    Location: minnetonka minnesota usa

    magnus Junior Member

    608/inline skate bearings are great as long as they do not get wet. To keep rolling resistance to a minimum lip seal drag is not acceptable so they are only shielded for racing and rec. Proper seal are nessecary for marine use. There have been many bearing upgrades which include ceramics which run without seals and reportedly servive rainey marathons to race another day. We are talking 5-10 dollars US versus 1 dollar for the standard shielded bearing.

    It will be fun to see what you guys come up with. Keep it simple and you will have a winner.
     
  13. magnus
    Joined: Mar 2010
    Posts: 72
    Likes: 2, Points: 8, Legacy Rep: 37
    Location: minnetonka minnesota usa

    magnus Junior Member

    As far as wheel material goes the urethanes (inline and skateboard) are heavy and will absorb shock and energy, so on a smooth track I would lean toward an acetal (delrin), it machines easy and does not absorb moisture like Nylon and they are both lighter than urethane:) You will want the black because it is fairly UV resistant and cost no more than virgin material:)
     
  14. upchurchmr
    Joined: Feb 2011
    Posts: 3,287
    Likes: 259, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    The reason I don't like the skateboard "wheels" had to do with the deflection of the urethane. Delrin works great for things you want to act as a wheel, not a tire.

    Marc
     

  15. magnus
    Joined: Mar 2010
    Posts: 72
    Likes: 2, Points: 8, Legacy Rep: 37
    Location: minnetonka minnesota usa

    magnus Junior Member

    So you should like acetal because it does not deflect much compared to urethane. We can compare acetal to steel or aluminum and acetal does deflect more there.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.