Yuloh's and single oar sculling

My father long ago told me stories about the amazing Yuloh's of Asia, a form of man-powered enginless propulsion, like a huge oar over the stern of a vessel, used to propel sometimes very heavy boats around harbors or canals. Dad served in the Royal Australian Navy and witnessed  junk-rig and sanpan boatmen manovering vesell's around with yuloh's on Hong Kong harbor in the 1950's. 

He described the mechanics and techniques of how it was done. But that was long ago, and it still remains a mysterious lost art to me.

However thanks to the internet, the veil is slowly being lifted. There are a few good videos out and a good video can be like 10,000 words, such as Yuloh's in China, posted by David Thompson on u-tube). 

There is also a discussion thread on the Investigator 563 forum with some good yuloh info. Rowing or sculling an Investigator

Here is a good link from the thread about Duckworks Yuloh device for small craft. Duckworks - Scullmatix (dinghy yuloh) 

Scullmatix - blade setup

Scullmatix - Swivel clamp device

The scullmatix device is a swivel clamp that joins an oar to a handle. It's clever design allows the power blade to swivel with minimal effort using the "falling leaf" method.

I gave single oar sculling a try on a Fatty knees8 dinghy row/sail trip to Magnetic Island (to visit the wreck of SS Adelaide)

Experimented with both the "falling leaf" and the "vertical blade" methods. The falling leaf method as seen in Davis Thompson's video seems far more powerful though more difficult to maintain with my simple straight rowing oar in a transom notch. The vertical blade method was easier with this oar but produced far less forward power for my dinghy. Of course my oar was a straight one, which made rotating the blade very tiresome work so i soon gave up. For a sculling beginner like myself conventional rowing is easier with conventional oars. 

However experts can make sculling look easy, here a good tutorial how to do single oar sculling of a dinghy by Charlie Briggs . 

A properly designed Yuloh has a downward bend located about the transom swivel pin which allows it to swivel the blade with minimal effort required. A  yuloh also has a large-area asymetrical power blade, which generates far more foward thrust than a simple oar.  It also has a foward restraining line, attached between the operators handle and the boats deck, which also makes it easier and less effort to use.

Here is a good masterclass yuloh lesson  (at 10-13minutes in video) Carol Hass - Yuloh on a Folkboat. Notice how her bent yuloh can stow on deck up forward. Carol has an interesting swivel join too.

Another yuloh is in use on Zeebedee, a 34ft junk rigged world-cruiser owned by Alan Martienssen.  Zeebeedee and Alan's story

This looks like a good way to make a cheap yulloh, the angle in the shaft should be 8-11 degrees. Yulohs - single handed sailing  there is allot of info here, and allot of reference links.

As for rowing an Investigator 563 with 2 conventional oars? The first question was "what length oar is required?" Cheasapeak Light craft - oar length calculator  calculated that i would need two (2) monster oars each 11 feet 6 inches long.!! Stowage would be very difficult, only possible if both oars were 2-part, so could be split in two 6 ft lengths each, and even then they would take up too much stowage space. A 2-part single yuloh starts making sense if is has to be stowed (under the cockpit for "Teria").