Plywood sampan for yuloh power

[Seafarer24]

I am looking for any information regarding yuloh-powered sampans. I want to build one to use as a large yacht tender. Building material will be plywood and method will be stitch-and-glue.

[YK GEO]

The yuloh sounds like more fun than rowing, esp cause you can look ahead without twisting your neck.

How about a long narrow rowboat design, one with a good sized skeg or wineglass shape in the rear portion, to provide some lateral resistance for the yuloh. I realize the yuhloh works kind of like a big single blade ossillating prop, but there must still be significant side thrust at the rear??

Try googling "plywood rowing shell". Somebody has a plan I've seen advertised, but I can't remember who.

Good luck!

[Seafarer24]

I would think it should be somewhat wide in the rear to handle someone standing up and swaying side-to-side... I do like the idea of a wineglass transom, though.

[gonzo]

Wooden Boat had an article on them years ago. They even showed the technique.

[Squidly-Diddly]

the idea would be to allow the paddle to flop back and forth may 15deg total so that the surface is at a better angle to push water.

Sort of like swim fins that flex on each stroke.

[YK GEO]

Hi,

I don't know if you've found this site, but it has a bunch of yuloh info. Sorry I didn't paste this properly as a link, but if you copy and paste into your browser's address it will work.

http://www.simplicityboats.com/yulohpage.html

Looks like you can use a yuloh with just about any kind of boat. A simple flat bottom rowing skiff built to Chapelle's rules, with a good sized skeg would be quick and easy to build (took me an afternoon) and pretty easy to move through the water, with the stability to stand in.

Let me know, and I'll post a couple of pictures of mine, which is really about all you need for plans.

Have a great day.

[TerryKing]

YK, Please DO post your photos; others are interested too!

[kayaker50]

On a related note: I built a plywood dory and tried to use a sculling oar for fishing because two oars are clumsy for fishing. My dory is too tippy to stand up, so I made sculling oars that would work while sitting. I tried several designs for the sculling oar, and the one that worked best was about 15 feet long (the dory is only 16 ft) with a 4 ft blade set at about 45 degrees to the loom, and the flat was horizontal. It had a D-handle like a shovel, which was a great improvement over the straight handle. But in the end, it proved too inefficient because it thrusts the water up and back instead of just thrusting back like a regular oar. It was fun trying, though... Chip.

[boat fan]

Maybe you could scale this down...

[boat fan]

Maybe of help....not plywood unfortunately.

http://freepages.genealogy.rootsweb....us_sampan.html

[messabout]

The yuloh has a blade that is angled down from the shaft only 8 or 10 degrees. More does not seem to work. Ask me how I know that. The length of the work boat yuloh is way out there, 20 maybe 25 feet. It hangs out the back of the boat a long way. Techie types will know why. The inboard end of the shaft has a short stick attached perpendicular to the shaft. A line is fastened to the end of the stick and is made fast near the floor of the boat. That bit of simplicity (damned clever those Chinese) makes the shaft rotate such that the blade assumes some angle of attack. A bit of geometry is involved no doubt. The user or users push or pull on the sweaty end of the shaft and the boat goes. On large boats a man will be on both sides of the shaft. They alternately lean on the shaft to make it swing while the rope and stick does the smart work of rotating the shaft just so.

I outsmarted myself a while back while figuring that I was capable of improving the age old yuloh device. Ha! I made a lovely laminated shaft with a sexy curve built in. I don't need no stinkin stick and rope. My curved shaft would rotate all by itself. The blade was the subject of my superior intellect also. It was a symetrical single cambered thing of beauty. Alas I have yet to make it work at all. Meanwhile I can remember messing about in Nassau. I watched, with profound respect, a nine year old kid in a crusty old Abaco dinghy. He was sculling that thing like it had a 5HP outboard. Not using a yuloh. He was using a straight oar of questionable quality. He made it look effortless. I wish I could do that.

[Tiny Turnip]

A couple of ply sampans, which might scale up:

Hannu's one sheet sampan:

Phil Theil's 'Sweet and simple' sampan: (which looks like a curvy punt to me. And whatever you do, don't spoonerize that!)

And some discussion and pictures of use of a yuloh with the 16' Winklebrig pocket gaffer here:

The thread is quite obvious in the 'engine' forum.

[YK GEO]

Hi,

I started a new thread for pictures of my boat, at "Sharpie skiff - Chapelle's rules", since it's not a yuloh specific design.

Geo

[ningpo]

there is a link to a yuloh construction. What seems to be missing but can be seen in the picture is the rope between the end of the bar and the floor of the craft. On the transom there's a pin with a ball socket, so that the yuloh user need only move the bar back and forth. The pivot combined with the rope causes the proper movement of the blade. The steering occurs with repeatedly pulling or pushing and not passing the middle until the desired direction is reached. Success. Anyone out there know if this isn't the forerunnner of the "longtail boat" , where the motor and shaft are the replacement for the yuloh?!

[BATAAN]

Originally Posted by messabout

The yuloh has a blade that is angled down from the shaft only 8 or 10 degrees. More does not seem to work. Ask me how I know that. The length of the work boat yuloh is way out there, 20 maybe 25 feet. It hangs out the back of the boat a long way. Techie types will know why. The inboard end of the shaft has a short stick attached perpendicular to the shaft. A line is fastened to the end of the stick and is made fast near the floor of the boat. That bit of simplicity (damned clever those Chinese) makes the shaft rotate such that the blade assumes some angle of attack. A bit of geometry is involved no doubt. The user or users push or pull on the sweaty end of the shaft and the boat goes. On large boats a man will be on both sides of the shaft. They alternately lean on the shaft to make it swing while the rope and stick does the smart work of rotating the shaft just so.

I outsmarted myself a while back while figuring that I was capable of improving the age old yuloh device. Ha! I made a lovely laminated shaft with a sexy curve built in. I don't need no stinkin stick and rope. My curved shaft would rotate all by itself. The blade was the subject of my superior intellect also. It was a symetrical single cambered thing of beauty. Alas I have yet to make it work at all. Meanwhile I can remember messing about in Nassau. I watched, with profound respect, a nine year old kid in a crusty old Abaco dinghy. He was sculling that thing like it had a 5HP outboard. Not using a yuloh. He was using a straight oar of questionable quality. He made it look effortless. I wish I could do that.

The yuloh and string thing... I always saw it done as "pull the string, pull the oar, push the string, push the oar", the string setting the angle, but not automatically. Worcester (Junks and Sampans of the Yangtze) stated that sometimes you'd see 4 guys on the oar and 2 on the string.
Working on Pirates of the Caribbean 2 and 3 on Grand Bahama I had to move a large heavy antique ship's boat from one side of the harbor to the other. Having learned to scull as a young man I jumped in, stuck a 14' oar out the tiller port, and did the 5hp outboard thing, even braking and backing into the slip. Next day our van driver, an older local man, paid me a large compliment when he said "I never saw a white man scull before."