Traditional Boatbuilding in Japan

Boat plan from The Tub Boats of Sado Island, by Doug Brooks. Available from the author. Click to enlarge.

Doug Brooks, the American expert in traditional Japanese boat construction, gave a lively, fascinating talk a few weeks back at Carpenter's Boat Shop in Pemaquid, Maine, speaking about tub boats and other types, as well as the state of traditional boatbuilding in Japan and the apprenticeship system there. What follows are notes and observations based on his talk, not a coherent treatment of a single subject.

Techniques

• Japanese boatbuilders generally use no clamps. They rely on the Spanish windlass and a multitude of props against ceiling, floor, and walls to hold things in place for fastening.
  
• Most strakes are edge-nailed to one another. An angled mortise is cut into the outside of the upper plank, near its bottom edge. Special boat nails are used: flat galvanized steel, somewhat curved, with an offset head. These are now hard to obtain, since traditional boatbuilding is virtually dead in Japan. The mortise is then sometimes covered with a small rectangle of sheet copper.


• Although planks are edge-joined, there is no caulking. Much effort is put into making a perfect wood-to-wood fit by "clamping" (see above) the two mating boards edge-to-edge, then running progressively finer saws between them. This is an exacting and lengthy process, but very effective. Japanese boatbuilders consider any seepage whatsoever that occurs on launching to be shameful, and they view the Western practice of caulking joints with suspicion -- viewing it possibly as evidence of a carpenter's inability to make a watertight joint through a good wood-to-wood fit..


• Most building is done in Japanese cedar. Little hardwood is available or used. Planks may be pre-bent over fire (live or charcoal), but not with steam or boiling water.


• Traditional craftsmen use few drawings and patterns, and those drawings which exist tend to be purposely incomplete, in order to protect "trade secrets." Patterns are usually just small bits of wood that show the proper angle for a particular joint. Everything else is in the builder's head.

The Apprentice System

• Students served a very lengthy apprenticeship -- as much as seven years. Even so, the master builder spent almost no time on instruction. The apprentice was expected to humbly absorb knowledge through observation...and through a process known as "stolen knowledge." If the master wouldn't explain a given detail, the apprentice was almost expected to sneak into the shop some night to copy patterns or otherwise figure things out. Although the objective was to duplicate the master's work, even so there was a saying, "The true craftsman must go beyond his master," improving on his methods in some respect.


• With the exception of Doug's book The Tub Boats of Sado Island, there are no comprehensive books in English on traditional Japanese boat building. Even in Japanese there are very few published works detailing the craft, and most of those that exist are monographs published by local museums, without national distribution. Neither are there any schools of traditional boatbuilding. Plans for traditional boats are not available. There are essentially no hobbyist-builders of traditional Japanese types.


• This is all partly due to the traditional secrecy of the master builders. They hoarded their knowledge, giving it up even to their own apprentices reluctantly. They would never commit designs to paper, fearing theft. Even today, with the last, aged builders passing from the scene, few will reveal their secrets. And given Japan's drive toward modernity following the Second World War, there were few young men interested in pursuing a traditional craft, and even fewer willing to serve the very lengthy apprenticeship required.

Doug brought a selection of tools to his talk. Photos follow.

Left: a pattern for the inside and outside curves of tub-boat planks and the angles of plank edges. Right: Japanese plane.

Red-headed item: an ink-line. The Japanese equivalent of a chalkline. The cross-shaped item is a tool for splitting bamboo lengthwise. The two interlocking pieces are wedge-shaped. Split bamboo is braided into hoops to hold tub boats together. (See drawing at top and next photo.)

A Japanese pull-saw, and a miniature example of the braided bamboo hoop for a tub boat. Doug says that braiding the hoops is the most difficult part of building a tub boat. They have to be just the right circumference -- to within a couple eighths of an inch -- in order to fit properly and provide the pressure needed to hold the boat together.

Doug is currently working on a book encompassing all four of his apprenticeships in Japan, with funding in the form of a publishing grant from the US-Japan Foundation. This book is due to be published (in English) in 2010 and Doug invites readers to email him their contact information so that he can let them know when the book is available.