Please visit our home site at www.TRILOBOATS.com.

Anke and I are off to build our next boat (the lead up at ABargeInTheMaking.blogspot.com). Connectivity will be limited to none, so you may not hear from us until we reemerge, some time in 2016. Until then, please feel free to browse the archives and leave comments where you will.

Fair winds!

Dave and Anke




Wednesday, April 18, 2012

YULOH: The Chinese Sculling Oar

No wind, slop and bobble. Yech.
 
Well I don't mind comin' and I don't mind goin',
But I'm some damn tired of rowin'!
From Old Fat Boat by Gordon Bok


Hootin', hollering days in our waters are more than matched by flat calms. These might be forecast winds that are noshow, or the limp end of a morning's suckapuff. Or the world might just go near breathless for a week at a time.

Drifting is an option. Drift with the tides and anchor up between. If things are right, we can cover a good deal of ground. But we still need to get in and out of the current. And in many times and places, the current never runs fair... surface flow might vary from a half knot to three knots against, depending on whether or not the tide is nominally fair.

If we're in very shallow, poling or, in moderately deep water, warping (rowing out and hauling a pair of anchors, one after the other, using them like long arms to pull us along). Nowadays, we have a pedal unit, but it's mechanical and beyond our ability to make or repair.

The main tool in our repertoire is the yuloh (Chinese sculling oar).

Leading edge of blade down about 45deg.
Yuloh in action... lanyard stays taut.

There are any number of ways to rig a yuloh. We use system with four elements. 
  • Yuloh - Loom and blade.
  • Deck lanyard (deck to end of handle) - this prevents the inboard end from popping up as the blade dives.
  • HMD plastic oarlock (HighMolecularDensity, aka cutting board plastic).
  • Oarlock Lanyard - attaches to a point on the outboard loom and keeps it from sliding outboard.
These four work together, taking the burden of controlling it from our shoulders. All that's left us is to sway back and forth, working the loom with our arms.

Our curved loom makes the blade want to spill to the correct angle. So we let it. The diving blade wants to make the handle ride at the top of the deck lanyard. So we let it. The loom wants to slide down and outboard, fetching against the outboard lanyard. So we let it.

The blade pretty much naturally wants to follow a falling leaf pattern... shallow figure-infinities (an 8 on its side), with the leading edge angled down. Breath. Feel it. Let go. Resist the urge to turn and watch it (you'll cramp up, quick!). Won't be long before you will be at one with your yuloh.

Chinese sailors were Taoist... it's all about easing along in sync with the world.

To turn, underway, just sidle a bit to put the tiller over as usual. Keep yulohing at the same distance off your body, and it will naturally help the turn. If you want to pick up the pace, slice the blade horizontal on the return stroke (for no power) and only stroke to favor the turn. If you really want to turn sharp (or without forward thrust), turn the blade perpendicular and shovel your stern around (like you were rowing off the stern).

 
Deck Lanyard snapped to Deck Ring

Canoe paddle handle with adustable lanyard (2 rolling hitches)

Oarlock and  Lanyard
(Gotta whip that end!)


Length and amount of curve are determined by your freeboard... the idea is to have the blade enter the water at about 45 degrees when holding the inboard end at sternum height. Curve can be anywhere from none to about 15 degrees. More curvature allows a shorter yuloh. Consider how much room you'll have in the cockpit... you'll want to be able to move around the forward end. Sketching it all out on graph paper saves a lot of trial and error.

Ours is (of course) quick and dirty. We look for a snow bent conifer, with the bend about a third-plus of the way from the base. This becomes the inboard, handle end at about 3 inches diameter, tapering to about 2 inches at the tip.

We like a large blade - about 3 feet long and 8 inches wide, mounted perpendicular to the plane of the curve. We flatten both sides of the loom, and screw one side on (from loom set into blade 'feather'). Drill opposing holes in both feathers and lash the other on.

We shape the blade flat on the upper face (toward the convex side of the loom curve) and rounded on the downward face. Don't know if this helps, but makes me feel good.

We mount the yuloh, deck lanyard and oarlock to starboard (we're both right handed). We stand mid-ships, facing forward, and position the yuloh on a Line about 4 inches to starboard of our hanging arm (seems about right).

'Position the yuloh' means that the oarlock midline and deck ring (or equivalent) are positioned on the Line. Set the oarlock lanyard to hold the yuloh about centered on the oarlock. Affix the deck ring directly below  the end of the yuloh, it's length set so the handle is about nipple height.

You can fudge the position of the oarlock... more loom inboard means more leverage for the person working the yuloh, and visa versa. Don't sweat it... you can always adjust with the oarlock lanyard.

None of this is rocket science, unless you're a Japanese ryo master (their highly tuned version). Top speed is maybe two knots in a sprint, so brilliant design won't do much for you. We look for comfort of use (good height, handle, leverage, spring and stowage).

I hear a lot of numbers quoted as yuloh science, but suspect that has to do with different installations that don't translate well. Consider a prototype to get the proportions before putting to much work into a beautiful work of art.

The yuloh is really a magical device. To slip out of harbor to catch dawn's first breath, or into a cove at days end, with little more than a liquid swirl to disturb evening's hush... it's... it's...

Well, you just have to try it.




*****

Since this article was originally written, I've run across Some Thoughts on the Yuloh by Slieve McGalliard, R&D Director of the JRA (Junk Rig Association). Very good thoughts, indeed, including a general recipe induced from drawings and photos of Chinese Junks and Sampans.

I've written an update post here on our results with his recipe.

9 comments:

  1. good detial. next project,please more pictures of your boat,bought your plans,will start building the DRAGION LADY soon, good pic of ruder, carl

    ReplyDelete
    Replies
    1. Thanks, Carl!

      I've pretty much used up the pics I have around the blog. See the SLACKTIDE label on the right-hand side-bar, or the slide-show at

      http://www.triloboats.com/SlacktideSailSlides.html

      Time to sail off and take some more! We've just ordered a video camera, so should have some live-action coming soon.

      Dave Z

      Delete
  2. Hi Dave, thanks for the interesting description and pics, have used a sculling oar on yacht for many years but never quite got it all set up properly as a yuloh yet. How does the yuloh compare to the peddle powered propeller you used to have?

    Cheers

    Ben

    ReplyDelete
    Replies
    1. Hi Ben,

      The yuloh isn't quite as fast as the sea-cycle, by about a quarter knot, and lower thrust (can't work against as much headwind). But the yuloh's more maneuverable and has a better 'feel'. For me, that is, Anke loves the cycle.

      Over long hauls, the yuloh will eventually start stressing the elbows, while the cycle, being in the legs, goes as long as your aft end can stand it.

      We have both, now, with the yuloh to starboard and the motor to port. We tend to use the cycle in open water, and the yuloh in close quarters or to give our behinds a break.

      One perk is, that around whales, they seem to hear and note the prop better than the yuloh blade, and don't come (quite) as near... we get the feeling that just the yuloh or sail can surprise them.

      Dave Z

      Delete
  3. Ha, funny to hear you talking of trying to avoid whales. Round here we consider ourselves very lucky to even see one! Mind you I did hit a slumbering sperm whale once mid Tasman while surfing at around 15 knots. Rather a nasty fright for both the whale and us. Very lucky it didn't sink us...

    What sort of distances can you comfortably cover with the yuloh and sea cycle combination on a glassy day?

    Cheers

    Ben

    ReplyDelete
    Replies
    1. Hi Ben,

      Quite a wake up for both of you!

      How far we get depends on the current, but can generally figure on 12 to 16 nm in two six hour periods... maybe 20 if we really apply ourselves (seldom the case).

      Dave

      Delete
  4. I keep hoping that you will resurrect your blog :)
    John

    ReplyDelete
  5. Been almost a year since you've posted. I hope you and yours are doing well, looking forward to reading about your adventures over the past many months, and wishing you fair winds and following seas! Be well :)

    ReplyDelete
  6. Hey Folks,

    We recently were handed a new formula for the Yuloh... our prototype is not fully implemented (fudged it with materials on hand), but develops a bit more power, already.

    What's striking is that it is much easier to work, avoiding wrist effort I didn't even realize was required.

    I'll be writing up a post, soon with the formula and new pics. Meanwhile, this article is officially out-of-date.

    Dave Z

    ReplyDelete