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Monday, March 12, 2012

Chinese Bamboo Rafts Redux

Continuing yesterday's discussion on the bamboo rafts of China...

Model of a Taiwanese bamboo raft. These were up to 35 feet LOA by 10 feet beam. Photo from Greenhill.  (Click any photo to enlarge.)

According to G.R.G. Worcester in The Junks & Sampans of the Yangtze, "Much interest attaches to bamboo rafts in China, for here we probably have the Chinese ship in its most primitive form. From it, doubtless, evolved the various types of junks as we know them to-day." This view is confirmed by others, including Basil Greenhill, who states in Archaeology of the Boat: A New Introductory Study that the model in the photo above "shows the basic palimped shape, characteristic of all Chinese craft."

The model of the Taiwan raft shows an ocean fishing vessel. But long before the Chinese went to sea, they were doubtless using bamboo rafts for everyday transport on inland waters.

The advantages of bamboo for raft building are substantial. With its sealed, hollow segments, it is far more buoyant than solid timber of equal diameter. Put another way, it is far lighter than solid timber for an equal amount of buoyancy. Not only does that make it easier to maneuver in the water, but it also makes it easier to haul out of the water at the end of a voyage, contributing to its longevity. Construction, too, is far easier: cutting down and positioning bamboo culms would be a piece of cake compared to working with logs for a comparably-sized raft.

The chu-p'ai, or bamboo raft shown above was used, according to Worcester, on the lower and middle Yangtze "wherever a strong and inexpensive craft is required for work in very shallow rapids. These craft are also used as tenders to wood rafts or for ferrying passengers and cargo from place to place." The craft shown is about 30 feet LOA and a little over 5 feet wide at the bow.

In addition to the visible frames, the bow is held together with a slat that passes through slots cut through the bamboo poles. Some longitudinal stiffness is provided by a kind of toe-rail along each side (#3 in the side-view). The raft was propelled by 15-foot oars worked against four tholes (#7), each about 2 feet tall.

A fa-tzu, from Worcester. Click to enlarge. Please forgive the gutter between the pages, which the scan could not avoid.
The fa-tzu, above, used on the Yachow River, a tributary of the Upper Yangtze, is capable of carrying cargoes of 7 tons on a platform that runs down the centerline, raising it a bit above the water that would constantly wash over the decks. Built in lengths up to 110 feet LOA, they were, according to Worcester, "the lightest draft general cargo carrier of the Yangtze, and quite possibly of the world" with a loaded draft between 3 and 6 inches.

The 110-foot LOA fa-tzu shown was made from bamboos very regular in diameter, at about 5 inches. Lengths, however, were unequal, so that joints between pieces were staggered between neighboring "strakes." The slick outer surface of the bamboo is scraped off and the culm is then dried for several weeks to reduce its moisture content and weight. All fastening is done with lashings. Live fire is used to bend the culms for the upturned bow, which is help in position by a bridle (#2 in the illustration) leading to an iron bar (#4). At the stern is a tiny shelter for the crew (#10), just forward of which is a brazier (#11) on which they cooked their meals.

Built for very shallow water, the fa-tzu was designed to flex as it slid over rocks and shoals. When moving upstream, it was man-hauled with ropes, moving at a rate of 5-10 miles per day. Downstream, just three men worked oars against tholes (#7, 8, 9), making the 100 mile trip in 20 hours.

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