Sculling, page 3 |
The Bahama·style oar (Fig.3) is much bigger, 12-feet long and more, as it's designed to move boats ranging from heavily built 12- or l4-foot dinghies to sloops in the 25-foot range. The blade is extremely long in comparison to its width. In section, the oar is usually a shallow diamond or triangle used flat side down. Bahamian boats offset the notch to port, making it easy to stand in the boat's center and keeping the right hand free for fishing.
The sculler stands, facing forward, and takes a long stroke, effectively using body weight. With the oar on the port side, it must be angled a bit more on the pull stroke to keep the boat running straight. The right hand can be used to give an extra push when starting on the push stroke and leaning into the push and it can assist the left on the pull stroke. The diamond-shaped section keeps tiring wrist twist down. Good scullers are said to need only a very shallow notch, but the oar tends to jump out when mishandled. A conventionally deep socket or oarlock makes sculling much easier for the less experienced.
The Chinese yuloh is a blade-heavy oar, often made of two or three straight pieces set at an angle so the blade curves down into the water. Unlike western oars which use a notch, lock, or socket on the boat, the yuloh has a socket cut or let into its bottom, and it rests on a pivot. Traditionally, this pivot was smith-made iron or carved hardwood. For our experiments, Sam Manning rigged up a trailer ball on the stern of his skiff (Fig. 4) The oar has a rope or string leading from the underside of the handle to a point on the sole in line with the pivot and the blade when the yuloh is in "neutral." The rope keeps this blade-heavy oar from tipping off the pivot and, more important, does the work of reversing the pitch or angle at the end of the stroke.
A yuloh needs no wrist rotation at all. Two hands are used, one on the handle, one on the string. The string hand always leads the oar hand, imparting the required pitch to the blade. Reversing the angle rakes a quick tug on the suing. We novice yuloh users found that if the stroke was too long or the pitch too great, the oar wanted to roll off the ball at the end of the stroke.
In section, a yuloh can be found with flat side up or down. With flat side down, the advantage is the same as is with gunning or Bahamian oars: The oar reverses pitch easily at the stroke's end. Theoretically, however, flat side up is more efficient. When an oar has its curved side down, lift works in the direction of the boat's travel. Only yulohs, however, can take advantage of this, as the string does the twisting. Free oars are almost uncontrollable with the curved side down.
Yulohs can be very large. Worked with gangs, with one or two pulling on the rope and three or four pushing and pulling the oar back and forth, they can run 25 or 35 feet long in sampans of 50 or 60 feet. Smaller sampans in the 18- to 20-foot range would use a yuloh of 13 to 15 feet. With these oars, 3-1/2 to 7 feet of blade might be underwater --- more on the longer oars. The Chinese don't seem to use yulohs on small boats, and a Western-style oar is probably better suited to boats under 16 feet unless they are heavy powerboats or sailboats.
As far as a yuloh's performance is concerned, an 18-foot Shanghai harbor sampan using a 13-foot yuloh could run at about 3 mph when propelled by one man. Roger Taylor, president of International Marine Publishing Co., has used a 10-foot yuloh on his 32-foot sloop Aria. He claims 2 knots in a calm, not bad for a 5-ton boat.
Vertical Stroke Oars
Oars for the vertical or slalom stroke are much less specialized. The one most often seen is the steering sweep of surfboats and whaleboats. These sweeps have the length and long blade of the horizontal oars. A 30-foot whaleboat has a 20-foot steering sweep with a 6-1/2-foot blade, which makes the sweeps quite blade heavy and flexible. Because the blade has a symmetrical section, either convex on both sides or diamond shaped, the sweep also can be used with the horizontal stroke. Steering sweeps often have a peg in the handle in line with the plane of the blade, so two hands can be used.
The oar designed by Douglas Martin (Martin Marine, Box 251J, Kittery Point, ME 03905) is the only recent innovation I've seen in sculling oar shape ( Fig. 5). Meant for a vertical stroke, the blade is asymmetrical in plan, with a long curving leading edge ending in a small half fishtail. In section, it is a symmetrical airfoil, with the thickest part at the leading edge.
The blade flexes and twists through the strokes like a propeller or a fishtail. Only a few degrees of wrist rotation is needed -- pushing it straight back and forth seems almost enough. A most efficient oar for small boats, this oar is large and powerful enough to use all the power you can put into it, and it's made in two pieces for easy storage.
Sculling Sources
For detailed information on yulohs, see
G.C.R. Worcester, Junks and Sampans of the Yangtze (Naval Institute Press, 1971).
Roger C. Taylor's The Elements of Seamanship (International Marine, 1982) describes his yuloh, with a drawing by W.H. deFontaine.
A little booklet by W.R. Johnson, Jr., Bahamian Sailing Craft Exploration Ltd., 1973), provides some nice drawings and descriptions of these boats and their use.
Chinese Yuloh
