Tohoku Isobune - Day Ten

Truly its hard to believe how fast this boat is coming together.  I mentioned that Mr. Murakami told someone that of course it was going quickly because he had Angela and I there to "help."  That is kind, but a stretch.  Today Angela pointed out his wife has said several times to people that of course its gone fast because Angela and I do all the shop cleaning!  True, but the real answer is Murakami san himself, who has refined a mostly traditional process in some very creative ways.  He can also just work darn hard.  I am trying to catch up with the boatbuilding in this blog post, which represents two day's work on the boat.

The offcuts from the stern of the side planking are laid over the aft planking to form a second layer of reinforced planking in this area.  

A shot of Murakami piloting a hole for a nail fastening the rubrail.

A shot of a clench nail from the side of the rub rail through the planking.

The rub rail dives in flush to the planking at the bow, a feature I have never seen on a Japanese boat before.

Aft the plank reinforcement is clamped in place with dogs then clench-nailed.

The director and curator of the local museum stop by and share an article with us about another local boatbuilder, long since passed away.

Note the boatbuilding working outside, holding the backbone of the boat in place with stones.  Sadly, the author of this book was killed in the tsunami.

Murakami san told us sometimes boatbuilders worked at their customers homes and therefore had to improvise and work outside.  He said some customers demanded to be able to watch the process!

Roughing out the stem, though this photo illustrates chainsawing in sandals.  Disclaimer: do not try this at home or at work.

The hatch over the live well, aft floorboards visible behind.

Murakami san roughing out the stem with an axe...

... and an adze.  He calls the axe the masakari, which is a term used in northern Japan (ono everywhere else).  The adze is the chouna. 

Murakami san told us he planted this hinoki himself thirty-five years ago.  By the way, this is a false stem, applied to an inner stem which our planks are nailed too.  Again, this is a first for me in Japan.

Down at the cove there are two four-plank boats that feature rabbeted stems and here is a look at the joinery that is visible in the stem/keel connection.

Murakami san built this boat but said a rabbeted stem was a pain to build.

Enclosure aft under the shelf at the transom.

Angela may have taken the photo of the project.  The light is perfect and she caught wood chips in midair.  Murakami san stood on the bow and adzed a recurve in the head of the stem.  His work with the axe and adze is impressive.  

Read Angela's impressions of the project at her blog: http://angelarobins.com/blog

Day EIGHT???

It's hard to believe but the last boat photo here shows what our boat looks like after just eight days of work.  Tokyo Television asked him how it could be built so quickly and he answered, "Well, there are three people working on it."  That is incredibly generous of him (or maybe he was being a bit sarcastic) because all I have done is rough cutting and planing (with power tools) and a little bit of finish work.  Murakami san also has me drive and set nails when his arm gets tired.  Angela and I keep cleaning the shop and fetching his tools, and on this day I invited her to join me in debarking some hinoki with an axe when Murakami san asked me to do it.  But really 95% of the work is his.

Today, Sunday, we had a day off and visited a house and tool museum.  I'll write a separate blog post about those adventures.

Our forward beam, called a kanugi, is tapered slightly and driven tight through the hull, then wedged in the narrower tenon to fix it in place.

Murakami san uses these two straight sticks to sight where the plank ends at the face of the stem.  I only just realized this boat is being built with a two-piece stem (sometimes called a false stem).  Murakami is the first boatbuilder I have seen do this in Japan.

We rolled the boat on its side in order to nail through the bottom and into our three bulkheads.

This shows how deep the bottom is charred by the fire bending.  We covered the bottom seams with battens to protect them from burning, but a fair amount of the bottom aft is charred.

Two hinoki planks, cut from the same log, will be our rubrails.

Angela using an axe to take the bark off the base of the same hinoki, which will be our outer stem.  Please follow her blog: angelarobins.com/blog

Murakami's bevel board for the rabbet in the rubrail.

As he advanced his cut he changed the bevel accordingly.

The rabbet ends short of the bow.

Murakami makes a cutout in the planking to receive the rubrail.  In the West we would cut a gain to allow a plank to overlap another and lie flush at the bow and stern.  This is an alternate method.

Amazingly he used an adze to work this small detail.  We actually both wondered if he was showing off but there's no need for that; he's impressed me already.

A slight gain is visible but really this is a completely different method to achieve the same result.

Note the use of prop and wedge to hold the upright timber so he can clamp the rail.

Day Eight is a wrap!  

Quiz question for readers: What is this for?  Answer below.

Self-service rice hulling and washing station...

Japanese Joinery

Today Murakami san installed a bulkhead and two main beams in the boat.  The joinery is very interesting, but well understood within the Japanese boatbuilding tradition.  Many types of small boats (and Edo-era ships) were framed with only horizontal beams, which typically were through-tenoned in the planking and wedged.  I will leave it to captions, below, to try and describe the process.

Murakami san pounding the endgrain of the bulkhead, while Angela looks on.  An earlier post talks about kigoroshi, pounding faying surfaces to get a watertight fit.  Basically this is Murakami san's go-to technique, at the expense of other techniques I have been taught in Japan.  The compressed wood fibers will swell tight in the seam once the boat is in the water.

Murakami san using a saw to fit the bottom of the bulkhead to the plank keel.  This is called suriawase, a technique commonly used by boatbuilders, but used only rarely (perhaps only here) by Murakami san.

He used an L-shaped took to reach inside the beam mortise and pound its edges.

The beam is passed through one mortise far enough so the other tenon can drop inside the boat and be inserted in its mortise.  The tenons are shouldered on the top only.

Murakami san drives the beam back until it shoulders against the planking on the right.

He then wedges the hull open about 3/4 of an inch on the starboard side.

Note the angled cut in the beam.  The piece on top is the offcut, let's call it a key.  He has spread glue on the beam and the offset will fit tightly back in place, but note the small wedge-shaped "tenon" left at the other end of the key.  This will fill the top of the mortise and lock the key in place.

The finished joint seen from inside the boat.  The beam rests on top of the bulkhead.

The mortise flares open aft and Murakami san inserted a cedar wedge, spreading the beam end to fill the mortise.  This gets cut off almost flush later.  The beams are hinoki.

Angela and I have talked about how crucial kigoroshi is to Murakami san's building and we recognize that we need to make step-by-step, detailed documentation of how he uses this technique.  We'll have lots of photos and video but Angela is working on drawings showing the process.

Kigoroshi Boat

Again, veteran readers of this blog will have read the term kigoroshi before.  Literally, “killing the wood” it refers to Japanese boatbuilders’ practice of hammering the faying surfaces (the surfaces that meet one another) of planks before joining them.  The idea is to compress the wood fibers prior to fastening, and once the boat hits the water and those wood fibers spring back the seam will become tighter still.

Murakami san uses this technique to a degree I’ve not seen anywhere else in Japan.  He claims its enough, along with putting glue in the seams, to ensure that the boat will be watertight.

Some shots here as well of his use of the axe.  It is his go-to tool for rouging out wood, but he cuts confidently to within 1/8th of an inch of his line.  Here in the north the axe, normally called the ono in Japanese, is called the masakari.

And, I don't know if anyone is counting, but this is just Day Four and it sure looks like a boat!

Roughing out the keel plank aft with an adze.

Murakami san checking the angle of the transom.

Beveling the top of the transom.

Transom glued and nailed in place.  We use the dogs to clamp just about everything.

Stem/keel connection.  

To bevel the sides of the stem, Murakami san sighted across his square, aligning it with the side of the plank keel.

These lines, drawn on a beam in the shop, give Murakami san all the bevels he needs to cut the joint on both the stem and keel.  Of course these are not labeled so only he knows what they mean.

Murakami san's method of preparing the seams can yield extraordinary results.  Here is the seam in the transom.  You can only find it because of the difference in the grain of the two planks.

Murakami san left the transom about an eighth inch wide on either side.

He then aggressively pounded the saying surface.  He worked both sides of the transom for several minutes of intense hammering.

The entire face compressed flush with the keel.

He and I then pounded the entire length of the keel where the side planks will fasten.

Angela looking at our backbone assembly complete, and our two side planks.

We propped the two planks in place right before the end of the day.  Tomorrow we fasten them.