Yuloh What I'm Talking About

[TomY]

I think you have a good idea, Will. You can pack a small electric, but most of the time, in sheltered water, oar power of some kind would be pleasant to use (for some of us) and saves your power.

Plus the Yuloh is easy to store on a 19' boat.

The oar on Venetian gondolas performs more as a sculling oar in close quarters. It's amazingly efficient propulsion for these heavily loaded boats in very tight quarters. The Gondolas haul tourists through very narrow channels, all over the city. Turning, docking, accelerating, even reversing. Outside of a jet drive, I don't think any conventional power would work as well.

The main difference from a Yuloh (I suppose) is the addition of the Focola, the twisted stout wood riser that the gondolier braces his oar against for these various maneuvers.

Then there is the 'flat out' position of the oar, perpendicular to the hull, where the gondolier can use his whole body for propulsion. I didn't see any flabby gondoliers.

 

[Will Gilmore]

The main difference from a Yuloh (I suppose) is the addition of the Focola,

Thanks for the post, Tom. I hadn't thought of that comparison before. Seems very similar. The focola actually looks very similar to the pivot of the yuloh, without the restriction of being attached. Many yulohs are actually mounted to the side like that too.
I wouldn't have the advantage of the gondola's deep rocker for maneuvering, but I think it will work quite well. I need to look at the use of reverse with the yuloh. That question was brought up by Ted. It's a good question.

- Will (Dragonfly)

 

[Snorri Eriksen]

Going to keep this thread going with some thoughts as my Yuloh design emerges. Here is the design work based on the Junk rig assoc. article I linked earlier in this thread:


I simply downloaded and printed profile drawing of my boat off of the sailboatdata site. I figured out the scale from the LOA and jumped off from there. Yielded about a 14 foot Yuloh.

Here are the materials I'm using: A good quality spruce 2X8X10 for the loom (shaft) and a 5/4 X 8 piece of pine for the blade. Could use better woods for durability but I thik these will be strong enough and they are cheap and light.


After the first step in the milling. I have the rough profile of the blade and two strips of spruce for the loom. Im going to laminate the loom out of two strips to attempt to add some stiffness to the rather flexible spruce.

One thing I haven't completely decided is how to make the pivot. Many of the traditional chinese models appear to be simply lashed on. The other option is a ball and socket like the charming wooden one shown earlier in this thread. Auklet appears to use a bicycle trailer hitch (designed to tow a trailer with a bicycle,) about a half inch ball. Then there is this custom bronze ball and socket plus cleat arrangement on a beautifully appointed folkboat:

The yuloh part is late in the video but the rest of the boat is also awesome. Worth noting that this shows an "american" yuloh with the bend in the loom located right at the fulcrum. Reading the musings of other sculling experimenters, those with this set up complained about the oar jumping off the pin. If you give this a hard think you will see that the only way a yuloh jumps off is if it is creating drag, and the geometry of this bend location means that drag is being created every time you change the direction of the stroke.

Last link for this over-detailed post:

This is a Stevenson Micro Cruiser. Very cute though slightly porcine boat. This guy appears to be quite effortlessly moving right along. A few things to notice: Most importantly it looks like he is using an ordinary trailer hitch ball for a pivot pin. The yuloh does not appear to be restrained to the pivot at all and it is not popping off the pin. He has no bend in the loom at all, which may account for his unusual lanyard arrangement. Very much looks like he intended to tie the lanyard down in chinese fashion but something didn't work. I suspect this is because without the bend in the loom the exact angle of the roll proved difficult to control. Seems to work for them.

I love the simplicity of this pivot rig. I found something on line called a "replacement ball for curt anti sway friction system" which appears to be a small trailer hitch ball 1" in diameter and proportionally slightly taller. I think I'll go with this as it is super simple, strong, and unlikely to catch on docklines etc. It might even prove handy to have a tiny bollard back there on the starboard side.

I'll keep updating this as the project progresses. Launch day is still at least two months distant up here in Maine so the field tests will have to wait.

 

[Will Gilmore]

Snorri Eriksen,
This is an awesome post.
My own research suggests the bend should be about halfway between the pivot and the end of the loom. I think you are dead right about why the ball and socket jump with the bend right there. The second video is the first I've seen with the bend at the blade. If you look at Sven Yrvind's video, he has added a short downward grip to which he attached his lanyard. The purpose of the lanyard is to prevent the forward force of the blade from lifting the loom and allowing that force to focus at the ball. I assume, the higher bend allows for more control when Sculling from side to side while changing the angle.
Since the blade acts as one propeller blade just switching its rotation at the end of each stroke, a wing like cross-section is desired. I also think there is another element to the propulsion. With the blade entering the water at an angle, like any incline plane, I think there is also propulsion provided from the lifting of the water and it falling down the plane. Therefore, my plan is to hollow the upper side of the blade to catch more water as it slides down the trough like plane.

Unfortunately, I'm busy trying to start a new business and farm so my own yuloh project is going to have to wait. The most important part for me is making it collapsible. I think your idea for the small trailer ball is a good one. I'm really looking forward to watching it unfold.
Thanks for this post.

- Will (Dragonfly)

 

[Will Gilmore]

Here is a quote taken from this site: http://triloboats.blogspot.com/2012/04/windless-running-on-grits.html?m=1
"
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."
It does a pretty good job of describing the parts and action of a yuloh.

- Will (Dragonfly)

 

[jssailem]

Great description @Will Gilmore.
On my 15 footer when I did not want to start the outboard, I sat on the bow with a paddle. I could skull/paddle the boat just about anywhere I wanted as long as it was calm and I had enough room. The stern felt like it was sticking way out behind. A little turn of the bow could have the caboose waving about smacking into all sorts of things.

 

[pateco]

Or you could try this method.

 

[Will Gilmore]

Or you could try this method.

Rowing blind

- Will (Dragonfly)

 

[pateco]

Rowing blind

- Will (Dragonfly)

He has two other people at the helm.

 

[Michael Davis]

I have seen set-ups like that on the race to Alaska boats ( no engines allowed ). Not sure I'd like to row a boat that heavy very far. ( shades of a galley slave!)

 

[Will Gilmore]

Here is an initial sketchup draft of my yuloh concept for Dragonfly. The pivot ball is attached to my transom solar panel arch (yet to build), maybe 18" inboard. The socket is located about 3' from the bend in the loom. The whole yuloh oar comes apart into about 4' sections, maybe pinned brass pipe in 5-1/2". The blade is around 4'long and I'm thinking 6" - 7" wide. I would make it concave on the top with plenty of camber on the bottom. The loom, I think, will be about 1-1/2" in diameter. All this is just a quick concept drawing laid out on an photo of Dragonfly. She's under snow right now so no measurements are exact.

-Will (Dragonfly)

 

[Will Gilmore]

Saw this video and thought it was worth checking out.

Very complicated and impractical for a sailboat but there are some ideas here.

- Will (Dragonfly)

 

[Will Gilmore]

I was just thinking about curving the loom, instead of having it break-down, to fit the curve along the sheer of the boat. It would stow along the toe rail that way and not take-up space in storage lockers or stand-out against the lines of the boat.
Typically, the loom is straight with a bend near the top to give a good angle and make Sculling easier. I have been wondering if a long smooth curve could accomplish the same effect.

- Will (Dragonfly)

 

[JRacer]

I think this is why God invented Mud Motors!

 

[Will Gilmore]

Mud Motors!

?
That is not a term I'm familiar with.

- Will (Dragonfly)

 

[JRacer]

?
That is not a term I'm familiar with.

- Will (Dragonfly)

http://www.mudbuddy.com/

 

[Michael Davis]

Actually saw a Yuloh at work a week or so ago. Twenty-five to thirty footer coming into harbour as we were going out. Just doing about 3kts. but that's all you want in a marina. It would double as a great emergency rudder as well, I think.

 

[Will Gilmore]

I have a big craft show that I need to make up a bunch of woodburning signs for RV and campsite, to try and sell, so I'm extremely busy trying to get at least ten of them done by march, but I can't stop thinking about my yuloh project.
I want my yuloh to break down into approximately (4) 4' section. I was thinking about using wood primarily, laminating it up with a hollow center for a heavy bungee to hold it together. I'd use brass tubing for ferrules at the joints. The other thought was a button lock like the extension poles on my portable canopy that I use at outdoor farmers markets and craft fairs.
What I'm interested in finding is a good cheap source for the tubing and hardware. Anyone have a supplier they could recommend?

-Will (Dragonfly)

 

[Will Gilmore]

This is the fulcrum designed by Sven Yrvind http://www.yrvind.com/yrvinds-yuloh/

-Will (Dragonfly)

 

[Tom J]

http://www.mudbuddy.com/

Reminds me of the Thai "long tails", a V8 motor with a long straight shaft and a little prop on the end that the operator lifted out of the water or pointed left or right to turn the boat. Would make one of a kind dinghy. Deadly in an anchorage.