Building a Tenma-Zukuri Chabune (伝間造茶船) – Part 5 – Final

First off, my apologies for taking so long to post an update on this project. The Tenma-zukuri Chabune is actually done. It sat for a long time with all the construction work done, needing only the coppering detail. I finally got the nerve to get back to it and it is now finished. But, when I last posted, there was still work to do, so let me take a step back to go over what was done.

Last we left off, the nail mortises had been cut and I was ready to add the decks at the bow and stern, or the omote and the tomo.

I don’t know if the boards that make up these decks were removable. Underneath, I left the ends open, so things could be tucked in there for storage, but only for smaller things, as the support posts of the beams cut the openings in half. If the deck beams were removable, there should be finger holes in at least some of the deck boards, so they could be easily lifted up. Sometimes, there was also a V-shaped pattern inscribed across the boards to make it easier to identify which boards go where. This is less important at the bow, where the boards lengths vary greatly, making them more easily identifiable as to which one goes where.

At 1/20 scale, I decided to keep things simple and didn’t add either finger holes or the alignment inscription. This would be more important on a larger scale model, like 1/10 or 1/15. So, adding the deck boards was just a matter of laying them down.

There are a couple ways to make these decks on a model. I think in reality, for removable boards, it would be necessary to add a strip of wood along the inside of the hull to create a ledge for the boards to rest on. For the model, I cut a card stock pattern to fit in place of the deck. Then, glued up the boards of the deck, and used the pattern to cut the one-piece deck to shape.

To help in this process, it’s useful to glue a supporting strip of wood onto the back side of the aft beam, as well as a supporting strip onto the inside face of the transom, or todate. This gives something for the template to easily rest on, and later the deck itself. The same is done for the bow deck.

I have been told by Douglas Brooks that these angled decks allow water to collect at the low ends, where small drain holes have been cut into the hull. This might suggest that this boat could have been used on Edo Bay, where the waters were rougher than on the canals of the city.

If this were the case, then the boat might have also had wooden platforms or deck boards installed on the floor of the boat to help keep cargo or passengers “high and dry.” On my model, I’m leaving the deck open.

That completes the structural details of the Tenma-zukuri chabune. The next thing is to add the coppering details. Copper was used extensively by Japanese boatbuilders to protect the ends of beams, to cover exposed nails, some wood joints, the tip of the miyoshi (cutwater), and sometimes the ends of planks. Copper has natural anti-bacterial and anti-fungal properties, which helps to prevent rot in those critical areas.

I spent a long time contemplating the adding of these copper features. I have a fair amount of experience coppering the hulls of ship models, and I’ve built several wasen model kits that incorporated copper coverings. I’ve also been simulating copper details using brown vinyl on my Kitamaebune model (yes, I’m still planning on finishing that Woody Joe kit soon!). But, it turns out that this is my first scratch build which features the copper coverings.

One of many different rolls of very thin copper foil I purchased on Ebay.

One of the considerations is that real copper coverings are secured by large numbers of small copper nails. This is done by first drawing a criss-cross pattern of lines across the copper in ink, then hammering in the nails where the lines cross, and the inked pattern remains as a decorative feature. I don’t know if it was always done this way, but it makes sense that it would be.

Now, one thing that has really intrigued me is that in just about every Japanese woodblock  print that depicts wasen, the coppering is black. This is not always the case. In prints of bezaisen, the big coastal transports, they are often depicted as a naturally tarnished green.

I’m guessing that in old Edo, when boats filled the many canals and rivers, the black painted copper was the style of the times. Possibly, this simply went out of style after the opening of the country, which is why we don’t see this in wasen built in the 20th century, except for the Marukobune.

Now, I’ve gone back and forth regarding copper coverings and the proper finish. It would be simplest to show plain bright copper, which will mellow in time to possibly tarnish on its own. But, the Tenma-zukuri chabune is based on an image from the Funakagami, which was published in 1802. That image shows blacked copper, not green or bright copper, so I started working out ways to fit it with blackened copper.

Since I need some uniformly shaped rectangles of copper, I experimented with ways of producing very regular pieces. I’ve used my Silhouette Cameo machine to cut vinyl, and I thought I’d try it out on thin copper foil, but it didn’t work out very well. I still think that if I keep at it, I might find a way to make it work, but so far, nothing. So, I had to opt for just carefully cutting narrow strips, choosing the ones that were most similar, and then cutting short length to fit the mortises.

The process really wasn’t so bad, but thin copper foil doesn’t lay flat very easily, and conforms to the irregularity of the surface of the tiny mortises. I would have preferred thick pieces that are much harder to cut.

In the meantime, I experimented with the use of Liver of Sulphur Gel to darken the copper. I bought a small bottle off of Amazon to experiment with and found that I could make it work. I considered pre-darkening the copper, but because the copper I finally ended up using was adhesive backed, I decided to try applying the patina after the copper was on the model.

Liver of Sulphur gel. It doesn’t smell very good. But, it seems to get the job done.

Basically, with the copper added to the model, I simply put a few drops of liver of sulfur into a large tub that I bought for the purpose. It has a locking cover, so the bad smell mostly stays in. I poured hot water to mix with the liver of sulfur. Then, I took a small plastic tray that I recycled from a frozen entree, and placed it inverted into the tub, so that it served as a stand for the model.

I placed the model on the stand and closed it up inside the tub, which was filling with liver of sulfur vapor. After several hours, it did darken the copper a bit, but I ended up having to leave it overnight to get the copper to darken sufficiently.

In the morning, all the copper had turned a very dark, charcoal gray. Very close to black, but not quite. There were some specks where I think there was some contaminant on the surface of the copper right at the edge. Perhaps some glue or something. It didn’t seem to be enough to worry about, but I might just take a tiny dab of black acrylic paint to it.

With the copper treatment completed, I then prepared a bottle of dilute black wood dye, and treated the bottom portion of the boat. When that was dry, I sprayed the whole thing with a coat of flat lacquer to protect it all. I finished up by adding some mooring ropes to the beams at the bow and stern, and by adding a plank across the beams that the sendō, or boatmen, might have used to walk over the cargo more easily. Finally, I added a couple sao, which were poles for maneuvering the boat.

One thing it seems is that perhaps the liver of sulfur vapor bath gave the wood a slightly aged appearance. The copper isn’t really as black as I’d planned, so it has a somewhat of a weathered appearance too. With the addition of the black dye on the bottom part of the boat, the whole thing looks more like it should be part of a diorama. It wasn’t what I was aiming for, but it looks interesting, and now I’m thinking to actually build a diorama around it.

The model is officially done, but I am planning out a diorama now. I have a case cover ordered already, and I’ve been experiment with making a small figure for the scene, which I may or may not use. I’m kind of leaning toward a simple scene of the boat tied up to some pilings along the stone wall of a canal, but who knows?

I’m very happy with the final appearance of the model, though it is on the small size for the public displays I’ve been doing. Perhaps, I need to build a bigger one, like Mr. Kouichi Ohata’s 1/10 scale version?  Ω

1 thought on “Building a Tenma-Zukuri Chabune (伝間造茶船) – Part 5 – Final

  1. Reblogged this on Ship Modeler and commented:

    Yes, I am capable of finishing a project. I’ve just been a bit burned out on traditional western ship models and have been spending more time on my Japanese boats lately.

    Also, in general, the Covid-19 social separation seems to be getting to me, and I’ve been finding it harder to keep motivated on my project these days. But, I’m doing what I can and today, finally got around to updating my blogs a little.

    Hope everyone out there is coping well!


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