Yuloh pivot

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  • 15 Jun 2012 17:48
    Reply # 973402 on 966615
    Deleted user
    Karlis K wrote:2:05 - 2:09, a whole 4 seconds of Easy Go action if anyone is in a hurry.  I spent a whole evening a few months ago watching all the "tellie-port" videos, great stuff.  Nice yuloh Bob, do you increase thickness as you taper the width? My shaft is a 2x4 after the 4.5' blade, and it seems a little floppy at the moment. 

    We used some black spruce barnboard and tapered the width uniformly from one end to the other. I think it is a little skinny and does bend some but the power is incredible. The yuloh produces vortexes in the water on each stroke. It is not difficult to go too fast with this yuloh. The challenge is attaining the right speed and maintaining its rhythmic nature.
  • 15 Jun 2012 16:15
    Reply # 973343 on 963296
    Arne Kverneland wrote:I haven’t tried it but I suspect that the fish-tail sculling technique, (where the same edge of the blade is always the leading edge) is a more high-gear version, better suited for prams and dinghies. This requires a different oar design. 

    This design has been described as "a complicated oar, but a simple outboard": http://www.youtube.com/watch?v=3PdOIXvfB3g

    Regards

    Robert Biegler
  • 14 Jun 2012 00:27
    Reply # 966615 on 958948
    2:05 - 2:09, a whole 4 seconds of Easy Go action if anyone is in a hurry.  I spent a whole evening a few months ago watching all the "tellie-port" videos, great stuff.  Nice yuloh Bob, do you increase thickness as you taper the width? My shaft is a 2x4 after the 4.5' blade, and it seems a little floppy at the moment. 
  • 13 Jun 2012 18:16
    Reply # 965870 on 958948
    Deleted user
    We met Chris and Jess of Teleport in St. Peter's last spring. Chris took a very short clip of the Easy Go Yuloh in action near the beginning of this short movie. The entire movie is certainly worth watching.


    Last modified: 13 Jun 2012 18:16 | Deleted user
  • 12 Jun 2012 21:31
    Reply # 963525 on 963296
    Arne Kverneland wrote:

    I haven’t tried it but I suspect that the fish-tail sculling technique, (where the same edge of the blade is always the leading edge) is a more high-gear version, better suited for prams and dinghies. This requires a different oar design. Again a slightly raised pivot position would probably help. That would be fun to try!

    Cheers, Arne

    Where I am now, at Whangarei, there's a little company that rents out boats by the hour. They have some one-man catamarans with a cycle-pedal drive connected to a plate underneath that works like a dolphin's tail, 90 degrees different from a fish tail. Now wouldn't that be fun to experiment with?
  • 12 Jun 2012 21:26
    Reply # 963520 on 963253
    Karlis K wrote:Awesome Ro video, David.  What's the story here?  Was this from an expedition of yours in Japan?

    Any idea what the call-response chant is?  Sounds something like: "ey-ya; oh-re".  Don't think I'll be able to use the yuloh now without hearing that in my head.
    Karlis,
    This was at the Hobart Wooden Boat Show in February last year. It's a major event for those whose boats aren't made from frozen snot or old tin cans. The Japanese city that sponsored the building of the replica brought it down to Hobart, and were inviting visitors to go out for a spin. Naturally, I was at the head of the queue.
    I don't know what the chant means, but it's just to keep in time (when you have 4 Ros a side and one at the stern, you need something), just like "yo ho heave ho". Kinda sticks in the mind, doesn't it?
    "ey-ya; oh-re  
    ey-ya; oh-re   
    ey-ya; oh-re"
  • 12 Jun 2012 18:49
    Reply # 963296 on 958948
    Anonymous member (Administrator)

    Stavanger, Tuesday

    I found that the position of the upper end of Johanna’s yuloh, at shoulder height, felt very right. In fact everything felt right except that I got too little resistance when sculling unless I used excessive pitch. I bet a bigger blade would have helped.

    I never felt any need for adding weight to the blade-end of my yuloh. My idiot-proof pivot kept the oar secure at all times and when I was to start sculling with the blade floating, I just needed a couple of fast high-pitch strokes to get the blade down in position and the lanyard taut.

    That Japanese ro with the handle on the upper side no doubt has the bend cleverly tuned so that only a light force on its handle is needed to vary the pitch. On my test yuloh, the pitch mostly depended on where my right hand gripped the handle ("the wrench"). If I grabbed it close to the loom, there was little pitch. If I grabbed it close to the lanyard or by the lanyard itself, I got more pitch.

    The Eastern yuloh with its falling-leaf kind of sculling no doubt is a low-gear propulsion device; very good when the manpower to displacement ratio is low, but not fast. In the other end of that scale one finds the 6- or 8-oared gigs (in UK) where all that man-power and long waterline with moderate weight resulted in impressive speeds.

    I haven’t tried it but I suspect that the fish-tail sculling technique, (where the same edge of the blade is always the leading edge) is a more high-gear version, better suited for prams and dinghies. This requires a different oar design. Again a slightly raised pivot position would probably help. That would be fun to try!

    Cheers, Arne

    Last modified: 12 Jun 2012 19:00 | Anonymous member (Administrator)
  • 12 Jun 2012 18:12
    Reply # 963253 on 958948
    Awesome Ro video, David.  What's the story here?  Was this from an expedition of yours in Japan?

    Any idea what the call-response chant is?  Sounds something like: "ey-ya; oh-re".  Don't think I'll be able to use the yuloh now without hearing that in my head.
  • 12 Jun 2012 16:20
    Reply # 963158 on 961781
    David Tyler wrote: Arne,
    Your pivot point on the pushpit makes sense to me. The illustrations of passenger carrying sampans show a built up structure on the stern for the yuloh pivot.
     My attempt at a yuloh on my 9ft dinghy didn't work very well either, because it immediately became clear that the pivot needed to be much higher above the waterline than the top of the transom. I, too, lost interest.
    And my oars never fail, and are more powerful than a yuloh - just like your Yamaha.


    Hi David

    Your point about the need for the pivot to be quite hige above the water line is well made. I tried to cover this point by suggesting that the yuloh was designed seperately and clear of the stern of the boat and them the drawing moved forward onto the boat rather than designed to fit the existing transom. I think few experimenters realise the need for the higher point to get the necessary mechanical advantage. This may help explain the high stern to be found on many Chinese boats and sampans.

    Your oars never fail, but if you were trying to row the parent craft then the oars might not be more powerful, nor less tiring.

    Cheers,  Slieve

  • 12 Jun 2012 15:48
    Reply # 963122 on 962988
    Deleted user
    Jonathan Snodgrass wrote:

    I know nothing about Yuloh's but ... as usual ... one should never let total lack of knowledge debar one from contributing to a web discussion ...

     

    The enginless Contessa 26 which was at Plymouth during the recent rally got his Yuloh out and made very impressive progress around the outer reaches of Plymouth Sound.  From what I saw he appeared to have it working very satisfactorily.  (The fact that when the wind came up again his 26 foot sloop outsailed Lexia, our 32 foot schooner, is a separate matter which I, of course, put down to him not lugging round a ton of engine, diesel for engine, diesel for heater, diesel heater, liferaft, Tinker Tramp lifeboat, Jordan Series Drogue, a fortnights supply of fresh water, beaching legs, twice the numbers on board, etc, etc, Or am I making excuses? )  The owner is not an Association member but others  will know who he is and  how he may be contacted.  I think that the Hon Sec knows him. 

    The said Contessa "Mariposa" did indeed perform most elegantly at Plymouth.
    I noticed that Richard Burke, the owner, used two of Slieve's tips:-  
    1. A bungee cord to hold the yuloh down on to the pivot, and 
    2. A piece of heavy metal wrapped around the end of the blade to weigh it down.
    The pivot itself was a temporary affair that had become more or less permanent, because it worked.  
    The other lesson learnt was do not use your yuloh as a make-shift spinnaker pole, especially not when hanging on to the spinnaker once the wind has got up too much.
    It cracked under the strain, and Richard must make a new one.
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