Here's the pedal (well, more like stirrups, as I recall) powered version of a yuloh I was remembering (note the "h", at the end of "yuloh", and no space - I had apparently misspelled the transliterated term, earlier; thankfully, Google can interpret my errors!):
I think I have a brief verbal description of the mechanics of this arrangement - somewhere...
A more standard yuloh in use, exiting a dock/marina:
I'll see if I can track down the "recipes" I found for sizing the sweep to the vessel, shaping the blade, the angle of the "kink" in the loom, etc. The apocryphal story of the diminutive South Asian grandmother, perhaps with a grandbaby slung on her back, moving a heavily loaded sampan through a crowded anchorage, bespeak the efficiency of these sculling oars, in well-practiced hands. Because of the geometry, most of the work can be done by leaning/hanging the operator's body weight on the oar, with the downhaul rope resisting the thrust component of the hydrodynamic lift generated as the blade slices through the water, rocking about the stern pivot to change the angle of attack to match the direction of waggle.
A painting of a (Japanese?...I think so) ship with multiple ro or yuloh sculling oars:
I have no direct experience with these sculls, but it appears to be one of the better human propulsion means for small ( a few tons or less displacement) watercraft. I don't know how early these originated, but there is, at least, several hundred years of precedent for their use.