Building a Hozugawa Ayubune Model in 1/10 Scale – Final

This is the completion of my 1/10-scale model of the 15-shaku ayubune. This began with the cutting of the beams. I made the smallest beam at the bow, called the tsunatsuke, 1.5-sun square. The other two main beams I made 3-sun wide and 2.5-sun thick. I didn’t have any sugi of the necessary thickness, so I had to use two pieces glued together. I put the seam on the side of the beam in hopes that would make it less visible.

I used the beams as a guide to help me size the cutouts in the hull, which I cut with my Japanese Hishika, Super Fine Cut Saw, that I got from Zootoyz. It worked really well for this.

I found a supplier with the exact same saw in the U.S., but the cost for the saw was more than what Zootoyz charges, even when you add the international shipping. The one thing with this saw is that it cuts so easily, you have to be careful not to cut too much. For the final trimming of the notches, I used a scalpel.

First, I notched out the hull for the bow platform, called the omoteamaose, and the stern platform, called the tomoamaose. These were the easiest to deal with, since they are at the ends of the boat. So, I dealt with these first.

It was simple enough to add the omoteamase using a 3mm wood. I pre-cut the piece to roughly the correct size by inserting the piece into place and tracing out the extents in pencil. I could then glue the piece into place and sand away any excess using a large sanding block.

Next, I wanted to add the tomoamaose, stern platform, but I needed to add a piece that fits across the tomo first. This piece is hard to see in my photos, but I made this with a slight V-shape on the bottom edge, it’s 7-sun high in the center and 6-sun high at the sides. I sanded the top of the piece flush with the notch, then I added a piece of 3mm wood to fit across the notch and over the currently nameless transom piece.

Next, I dealt with the beams, beginning with the small one at the bow, the tsunatsuke. I cut the notch for it 3-sun aft of the omoteamaose. The notch is the width of the beam, 1.5-sun, and half the depth, or .75-sun.

I fit the beam into the notch and then marked the edges of the hull onto the beam. I cut just under half-way through using the Hishika saw, then used a scalpel to carefully shave away wood until the beam fit properly into place.

Photo actually taken after the stern funabari was in place and the hull was marked for nail mortises.

For the main beams, the funabari, I cut the notches to a depth of half the beam thickness, as it turned out, the seam from the 2-layer thick beams I made served as a perfect marker. With the notch cut, I could then trim the beam so that it fit tightly and cleanly. Again, the 2-layer beams worked out very nicely. Cutting half-way through, I could then pry the excess piece loose, which popped off nicely, requiring just a little cleanup.

On the real boat, the ends of the beam form dovetail fasteners that fit into the hull planking. I didn’t do this, though maybe I should have at least tried. Once it fit correctly, I glued the aft beam into place, then trimmed off the excess by cutting, again with the Japanese saw. While the saw is not a flush-cut type, it does cut very close and cuts very cleanly. It only took a few passes with a sanding block to finish up the joint.

The forward funabari was a little more complicated as it’s actually part of a 3-piece assembly, including a floor beam (I don’t know the name of these piece), and a vertical connecting piece called a tatematsu. Unfortunately, I don’t have any images of the construction process, but I basically made the tatematsu from a 1-sun thick piece of wood about 5-sun wide at the base and 3-sun wide at the top. I notched the floor beam and the underside of the funabari to fit the tatematsu properly using my smallest Japanese chisels.

The finished forward beam assembly.

Finally, I finished up the model by trimming out the mortises and adding wire nails where needed. For the nails, I cut steel straight pins into short pieces, filed one end flat, and treated them with some stuff from Caswell Plating that works great for blackening stainless steel. I drilled all the holes for the pins, which have a blunt end, and pushed them into place. Only friction is holding them into place.

Finally, I cut out the mortises using 1.5mm and 3mm straight carving chisels, completing the model.

The basic model is now complete. I may add a few accessories to the model, but probably nothing more than a bamboo pole, which was used to propel the boat, and a small, round bailer that looks something like a tiny wooden bucket with a handle sticking out one side.

For displaying models of this type, because it’s an open boat, I can’t fasten the hull down to anything, plus I want people to be able to see the mortise details on the bottom, so I will just find a nice contrasting display board to set it on.

I plan to add the model to my next Japanese boat models display, which I have been showing in the window of Union Bank’s community room in Japantown, San Francisco. I’ve only had one such display this year, as I wanted a new model or two, and this should do the job nicely. Ω

 

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Building a Hozugawa Ayubune Model in 1/10 Scale – Part 5

Progress continues with my 1/10-scale model of the 15-shaku boat used on the Hozu river, northwest of Kyoto. I’m 6 months into the build, but I have certainly not spent a great deal of time in actual construction. Mostly, I’ve been contemplating how I was going to accomplish each task of the build. Things are progressing quickly now.

Ayubune model with former clamped to the baseboard fixture

With the new fixture holding things in place, I taped a piece of cardstock into place to trace the shape of the hull planking. I rough marked the outlines of the bottom, bow plank, and transom on it. The planking will be cut oversized, so getting the exact shape isn’t really necessary, except to make sure that the wood I cut is large enough, but not too wasteful of my limited wood supply.

Next, I cut four straight strips of 3mm sugi on my table saw about 1 shaku wide and 16.5 shaku long. There are two hull planks on each side of the boat, but unlike many other wasen designs, the planks fit flush together, so the sides of the boat are perfectly flat. So I glued up the planks into two side-by-side pairs.

When the glue was dry, I traced the pattern outlines onto the planking in pencil and then cut them out a little oversized to allow for errors in measurement. The main issue here was that I wanted the row of mortises, which I will later cut into the hull planks, to be fairly level with the hull bottom and also low enough so that the plugs stay well below the top edge of the shaped plank.

In this photo of an Ayubune, you can see the row of mortises in the upper plank on the right side of the boat. Photo courtesy of Douglas Brooks.

With the hull planks rough-cut, I marked out locations for the nail mortises. I set these 7 sun apart, 1 sun from the plank seam. The mortises are trapezoidal, like the ones I cut for the shiki, or bottom, and 3 sun long.

Locations and extents of the mortises were marked first.

The full outlines of each mortise was then drawn.

Both sides are shown here. The one in front has had the mortises cut. I will cut these a little deeper so that the plugs will seat better.

Plugs shaped and inserted using the method explained in a previous post.

Showing some of the plugs glued into place. The tools used in cutting the mortises are above.

The plugs, trimmed and cleaned up.

When all the mortises were cut, plugged, and everything was dry and cleaned up, it was time to glue the hull planks into place. The first thing to do was to test fit them into place to make sure I didn’t screw anything up and that everything will fit correctly. This required that I remove the former from the base, though there were probably ways I could have come up with to hold the planks against the former while it was on the base. As it was, I ended up using spring clamps and rubber bands.

I had to pre-bend the planks to minimize the number of bands and clamps needed. This was a little iffy, since I used Titebond to glue the mortise plugs and to glue the planks together. Original Titebond is not waterproof and it’s not particularly water resistant, but I like to use it as it’s easy to clean up.

Also, before gluing the planks into place, I realized that the bow of my model was too wide and needed to be narrowed, so I sanded it down before proceeding. During the process, it popped loose from the model, but this only made it easier to shape. Afterwards, I glued it back into place.

It took a little while before I was confident that the alignment of the planks would be okay, but then I went ahead and glued up the planks.

Once the glue was dry, I could remove the former. I had a few issues where I didn’t have a good glue joint, so I had to re-glue some seams. At this stage, it’s a little delicate, so a little care has to taken with the model.

Next, I’ll be trimming away excess and adding details.

Building a Hozugawa Ayubune Model in 1/10 Scale – Part 4

Something I didn’t mention last time was that I had cut a paper pattern for the shiki and rubber-cemented it to the assembled . I then cut the wood to the pattern. Since the plans I have show the lines to the inside of the planking, I left the pice a little long at the aft end, as the bottom extends slightly beyond the transom.

Shiki with pattern, and cut to shape, with extension at the aft end

The final pieces are ready for assembly. As on the real boat, the hull planks will be shaped in place. Note that I also cut mortises for the bow plank, which I’m told is called the omote no tate ita. I’m going to have to find the kanji to make sure I know what this really means. The same goes for the transom, or tomo no tate ita, but in other regions is called the todate.

Pieces these parts together in their proper angles presented a challenge. Especially since the hull planks need to be shaped in place on the boat. The real boatbuilders built the boats upright, and used wedges, iron dogs (like big staples), clamps and posts to push and hold things into place.

My traditional boatbuilder’s workshop diorama, showing a bekabune under construction

As a model builder, the best solution was to build this model on a mold, though without gluing or drilling into the model, it would be a challenge to hold everything in place.

I started with a longitudinal pattern, which would give me the angles for the bow and stern planks, as well as the proper curve of the shiki. I marked the only two station lines on the drawings and cut the cross-wise formers to shape based on the patterns I drew earlier.

A scroll saw and bench sander made quick work of the MDF particle board formers, and the station formers were cut up and glued into place. In the meantime, since the bottom has a slight curve to it, I wet the wood a little and used a fixture I made for holding it into place as the wood dried. It was important not to get the wood too wet, just damp, to keep it from dissolving the wood glue, as I only used original Titebond, not one of the more water resistant versions.

In order to hold the transom piece into place, I had to come up with some kind of notched piece that I pinned into place on the centerline former. At the bow, a simple clamp held it into place. The pieces were glue together and held on the temporary former with rubber bands as the glue dried.

Once dried, the tricky part began, as I had to hold a piece of card stock into place well enough for me to trace a rough outline for the hull planks on it. Not being blessed with 4 hands, I decided to try making a fixture to hold the assembly into place.

The base fixture is a simple board with a clamp that’s designed to hold the former securely. It’s nothing more than two pieces of MDF with a small piece at one side that’s the thickness of the centerline former, all glued together and down to a baseboard.

The clamp and the former are drilled through so that I can run a clamping screw through them. I drew registration marks on the pieces to make alignment easier.

The bottom assembly could now be held somewhat securely, allowing me to work on it and transport it without damage.

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Ayubune model with former clamped to the baseboard fixture

The next step will be to make the hull planks.

 

Building a Hozugawa Ayubune Model in 1/10 Scale – Part 3

My illustration of the ayubune, based on plan drawing by Douglas Brooks (with his permission). Position and size of details shown here are only approximate.

Counting up all the major planks, transom, and beams, this Ayubune model will be made up of only 17 pieces:

  • Shiki (bottom) – 3 pieces
  • Omote no tate ita (bow plank)
  • Todate (transom)
  • Tana (hull planks) – 4 pieces, 2 on each side
  • Omoteamaose (bow platform)
  • Tsunatsuke (lit. rope attachment) – Bow beam
  • Omote no funabari (forward beam) – 3 pieces
  • Tomo no funabari (aft beam)
  • Tomoamaose (stern platform)
  • Transom Strake

In addition to these, I made patterns in paper for obtaining the proper angle for the lay of the hull planking. I have yet to decide at this point just how I’m going to fix the hull planks to that angle. But, there’s time before that needs to be deal with.

My second illustration of the ayubune. I’ve labeled most of the parts here, but haven’t been able to get the names of all of them yet.

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Building a Hozugawa Ayubune Model in 1/10 Scale – Part 2

The ayubune is not my first Japanese boat scratch build attempt. The first was the Urayasu bekabune, a boat designed for working among the seaweed nets of Tokyo Bay. But, being unaccustomed to scratch building Japanese traditional boats, I was wresting with a few construction problems and a couple errors, so I set it aside. Then, I found the ayubune on Douglas Brooks’s blog.

The ayubune is a very simple design. There is no cutwater, the side are flush, making for a very simple shape, and there few details beyond the hull and beams. This seemed to be an ideal subject to start with.

Mr. Brooks recorded 3 sizes of ayubune in Japan, a 24-shaku, 18-shaku and a 15-shaku boat. I noted that he built at least 3 of the 15-shaku boats and posted photos and notes on their construction. At a traditional 1/10 scale, the 15-shaku boat would be just about 15″ long, which seemed like a good size.

Large, 24-shaku fiberglass ayubune usee to give river tours to tourists on the Hozu river.

15-shaku ayubune on which my drawings are patterned. Photo courtesy of Douglas Brooks.

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Building the Kamakura Period Umi-Bune, Part 6

As I mentioned in my last post on this model, I’d been wrestling with the configuration of the roofs. The 1/20-scale museum model that I often see reference on the web, differs from Professor Ishii’s 3-view illustration that I’ve mostly been basing construction on. Those drawings are more of a match to the early scroll paintings. Oddly enough, none of the models I’ve seen match them exactly. Is it possible that the builders had access to more updated information? Or did they just decide that the Ishii-san was wrong? But, then what about the scroll paintings? Are they simply written off as being wrong?

As you can see in the photo below, which was taken at a ship model club meeting, I initially made flat roofs panels. If I could justify them, they would certainly be the simplest to construct.

Flat roof panel initially constructed is seen in foreground.

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Building a Hozugawa Ayubune Model in 1/10 Scale

There are a lot of potential wasen subjects to model, but good plans are difficult to come by. Also, when decent drawings are found, it’s often difficult to find or to understand the details of the subject. I’ve been toying with a lot of different possible model building subjects, but would usually run into some issue that kept me from pursuing it further.

Recently, I sort of re-discovered a subject that I seem to have overlooked before. It is a boat that Douglas Brooks wrote about in past blogs from about 3 years ago, when he was building a boat in Kameoka, Japan, which is about 16 miles west of Kyoto. There, he built a Hozugawa Ayubune, a type of simple fishing boat that was used on the Hozu river.

15 shaku Ayubune built by Douglas Brooks in Kameoka, Japan, in 2014. Photo courtesy of Douglas Brooks.

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Building the Kamakura Period Umi-Bune, Part 5

Umisen Model

Model on exhibit at Kanagawa University. Photo by Masami Sekiguchi.

 No, that’s not my model. This 1/10-scale model of a Kamakura period umi-bune is on display at the Kanagwa University, which is home to the Institute for the Study of Japanese Folk Culture. The photo was taken by my friend Masami Sekiguchi, who is one of two Japanese ship modelers I met with in Tokyo last September. The other is Norio Uriu, Both gentlemen are members of The Rope, the Japanese ship model society in Tokyo.

I had been corresponding with Mr. Uriu for over a year, as he is a friend of fellow ship modeler Don Dressel of the Ship Modelers Association in Fullerton, California. Don was building his model of a Higaki Kaisen at about the same time I was building mine, and at some point, he put me in touch with his friend in Japan, Mr. Uriu.

When I travelled to Japan, I made arrangements to meet with Mr. Uriu for dinner in Tokyo and he brought along his daughter Hanako, who helped with our discussions, and Mr. Sekiguchi, who has been helping me understand information on Japanese ever since.

Mr. Uriu actually got myself, Mr. Sekiguchi and Jean-Pierre Mélis together, as we were all interested in the subject of wasen. Mr. Sekiguchi is a long-time member of the Rope and the Yokohama Sailing Model Club, where he served on the executive board for 14 years. I’ve mentioned Mr. Mélis before on my blog as he’s been writting a 4-part series on a look at traditional Japanese boats through paintings in the Neptunia, which is the Journal of the Friends of the French National Maritime Museum. The three of us exchanged many emails on the subject of wasen, as I work on my wasen models and Mr. Mélis writes his articles, the third of which should be appearing the March/April issue of the Neptunia.

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Another view of the Kanagawa University model. According to Mr. Sekigushi, the model was built by the late Yuichiro Kondo, a third-generation boatbuilder from Yaizu, and maritime researcher. Photo by Masami Sekiguchi.

Regarding the large umi-bune model at the Kanagawa University exhibit, this is is very similar to what I’ve been working on, and would represent the same type of boat. The 1/10-scale model on display varies only slightly from a pair of 1/20-scale models I have photographs of. One set of photos of the 1/20-scale boat were sent to me by Douglas Brooks, the other set of photos is from the Nippon Foundation Library website. The 1/20-scale models are nearly identical, though one is rigged and the other is not. I suspect they may have been built by the same person or persons.

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1/20-scale umi-bune model being prepared for exhibition in Kobe. Photo by Douglas Brooks.

One of the issues I’m looking at is that if you look closely at the 1/20-scale model photos, you may notice that the roof boards are short and run from the peak of the roof out to the sides. With the large 1/10-scale model and models of medium-sized version of the ship, the roof boards run the length of the yakata. Now, this may seem a minor issue, but it affects the underlying structure of the roof. Also, I don’t know that they’d both be correct for the exact same ship. Different time periods, maybe? It’s just another one of those things that I’ll have to make my own call on.

Kitano Tenjin scroll painting boat

Closer look at the umi-bune in the Kitano Tenjin scrolls.

As you’ll see next, I’ve just about run out of time to decide, as I’ve completed the basic framework of both the large and small deck house structures.


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Now, I should point out that I’m pretty much “winging it” when it comes to the structures. I’ve examined images of traditional Japanese carpentry and structure, and looked over my photos of houses from the Edo-period, though that’s 300 to 500 years later than this boat. I think this is basically what I’m seeing in the museum models, and I think it, more or less, works.

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I feel that I’m cheating, to a certain extent, as this is all going to be covered over by a roof, and the internal structure won’t be so noticeable. At 1/50 scale, the first issue I ran into was that these are very flimsy structures as glued together, and the only way I could keep them from falling apart was to drill out the joints and insert steel wire “pins”. These are hidden by the beams I added. It seemed odd to add beams on top of beams, the way I did, but I didn’t really see how else I could support the roof otherwise.
img_2472For the lower walls of the long yakata, I wasn’t sure what the texture in the drawings represented. They looked almost like simple rectangular lattice work, and I considered make them very similar to the way they are on the photos of the large model that Sekiguchi-san sent me. The Kitano Tenjin paintings didn’t seem very clear on this and it seemed to look like the walls were really entirely just a drape or maybe a roll-up screen. But, I tried to follow the drawings I’ve been using, which suggest these lower panels.

Considering they might be some kind of wicker work, at this scale, I just decided to cut a pattern using a knife. I stared by making very narrow strips of hinoki on my table saw. Basically, cutting them as narrow as I could manage. I glued these up, side-by-side, onto a thin backing board, and trimmed the piece to fit into one of the openings. For no particular reason, I used sugi, or Japanese cedar, for the backing board. I then cut lines perpendicular to the narrow strips. I was going to for a weave pattern.

As you can see, I also added the support posts on either end of the long yakata. I don’t know this for sure, but these seem to be present to allow the crew to easily stow the mast and sail gear out of the way. Also, the umi-bune in the Kitano Tenjin scrolls has a lantern hanging on a pole, which is attached to one of the forward posts, probably lashed to it. I imagine that nobori, or vertical banners flown by a daimyo’s vessel, would also have been lashed to these supports as needed.

Regarding the mast and sail, there is just the one mast, but the sail is supported by the yard at the top and a spreader at the foot. Basically, these are just two poles, probably identical. Because of the stiff nature of straw matting, sails weren’t furled on these early sailers, but were rolled up, and they had to be carefully handled, as they would become extremely heavy if they got wet.

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The Kanagawa University model shows straw mat sail as being made up of separate panels that seem to be tied together at the edges. Photo by Masami Sekiguchi.

At some point, I’ll make a sail for my model, but I don’t know that I’ll have time before the model is displayed at the Japan Center Mall as party of my next Japanese boat models display in March. A while ago, I purchased a sample piece of a very coarse weave cloth that I think will work well for my model. I don’t know if I’ll tie the panels together like was done on the Kanagawa University model, though it looks very interesting. More likely, I’ll just sew in the stitching in a large grid pattern to simulate the panels. I’ll have to experiment with it a little to figure it out.

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You’ll note in the above photo, I added the stern deck. I decided to simply use the natural ledge created by the overlap in the bulwarks planks to support the deck. I had done this at the bow as well. Again, I don’t know if this would be accurate or not. One issue is that those beams under the rails at the sides are set into the hull, but stop there. All other beams run all the way through the hull and out the other side. I didn’t see any sign of that in the models and drawings. However, it is possible that these rails at the stern should actually be sitting lower that they do on my model. If I do another model of this type, I’ll be revisiting the design here.

You’ll also see that I added the rowers’ platforms and support beams for the oars to push against. It took me a while to get comfortable with how these boats were rowed, and I still have questions about this. I’ve reviewed paintings and even the Battle of Dan-no-Ura sequence in the movie Kwaidan to wrap my head around this. The drawings of the Umi-bune showed some very flimsy looking beams that the rowers would pull hard against, and I just didn’t feel comfortable with how fragile they looked, so I used slightly heavier beams.

Based on the scroll paintings, the platforms in the drawing, and consequently on my model, seem awfully small too. I really need to see some figures on the model and to play with some oars to figure out how they would have rowed. One of the issues I have is how they rowed. Sculling oars are generally used with the rower facing forward. In all the early paintings, the rower is commonly seen facing backward, like a western rower.

The Kanagawa University document on the Kitano Tenjin scrolls, that I mentioned in a previous post, suggest that the kind of oars shown could be used like a pole to push the boat along as well as used like a paddle. If you look at the painting above, clearly, they’re not sculling –They seem to be pulling against the water, like a western-style oar. If they were polling along, I don’t know if it’s possible to get leverage against the bottom of a river or shallow sea floor that way. So, I’m guessing that they are rowing, western-style.

Yesterday, Sekiguchi-san gave me a new piece of information that might help research this a bit more. Already known, is that the Japanese word for oar is “ro”. Sekiguchi-san explained that there are two types of ro in Japan, a sao-ro and a tsugi-ro. The tsugi-ro is a two-part ro, with a head set at an angle to a long blade. The sao-ro is a pole type and is the type that would have been used on the ships shown in the Kitano Tenjin scrolls. I’ll probably be thinking about this a lot in the next week or two, as I want to add the oars to my model. So, I’ll be discussing this more in the future.

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The last thing I’ll mention here, is that I finished the mast support, adding the side pieces shown above. So far, I have no idea what the stair-step shape is for. It may serve as a rest for the sail spreader. Perhaps to keep it from flapping around, perhaps lines attached to the spreader are pulling back hard and hold the spreader against this support. Possibly, the yard is lashed to the mast support or to the beam behind it.

This is the only thing that make sense to me, but it would require the bottom of the sail to sit very low to the deck. If you look at the Kanagawa University model, the sail is mounted way too high, or the mast is too long, for this to work. But, perhaps that’s an error in that model. I’ll have to examine more paintings regarding this.

Building the Kamakura Period Umi-Bune, Part 4

Kitano Tenmangu

Kitano Tenmangu – Shinto Shrine in Kyoto. Photo from Wikipedia.

 

 

 

About a week ago, my ship modeler friend in Japan, Mr. Sekiguchi, explained a little about the Kitano Tenjin scrolls that depict the Kamakura period Umi-bune, and I have since re-read through online information on the subject to get a better understanding.

The scrolls represent the life of Sugawara no Michizane, a scholar and poet in the Heian period (平安時代  794-1185) who rose high in politics in Kyoto, then Japan’s capital. But, he had powerful  rivals in the Fujiwara clan that plotted against him, and he was exiled to Dazaifu on the island of Shikoku, where he died three years later in 903.

Apparently, there was much sympathy for Michizane, and shortly after his death, there were a number of calamities, including a lightning strike within the imperial palace. The emperor’s court fearing that these were caused by the wrath of Michizane’s angry spirit, decided to placate him by deifying him and erecting a shrine. He was given the Shinto name of Tenjin, and the shrine was built at Kitano, and known as Kitano Tenmangū.

The scrolls were painted a few hundred years later, during the Kamakura period, and there were apparently a few versions of them. The images shown in my previous blog posts appears to be from the scrolls known as the Jōkyū version, which consisted of eight scrolls, and date from 1219, fairly early in the Kamakura period.

If you really want to learn more about the Kitano Tenjin scrolls, I found an excellent 191 page English language pdf that you can download here: Kitano Tenjin engi pdf. This pdf publication discusses each of the elements of the scrolls. The last two pages even examine the umi-bune in the paintings.

As it turns out, the source for this is Kanagawa University, which is the home of the Institute for the Study of Japanese Folk Culture. I’d wanted to visit the exhibit hall on their campus during my last visit, but my schedule was too tight. I don’t know if it still there, but they had a beautiful looking wasen exhibit there.


The next stage of the model was to complete the hull planking. This was pretty straight forward. I’d already added the upper planks to the main hull, and just needed to complete the bow and stern sections. For these, I made patterns from the drawings and then trimmed the pieces up.

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As with the other planks, I used my mortising tool to create the stitch-like pattern along the bottom edge of the planking. I didn’t have a photo of it last time, but here you can see a couple shots of it up close.

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Again, the offset point was unintentional, but turned out very useful. This is nothing more than one of an inexpensive 5-piece steel chisel set. I don’t even remember where I got them – I think I was given these by someone. I’ve seen similar sets on the Micromark website.

I decided not to worry about the butt joint between the ends of the plank sections. I’ve seen museum models that show dark, short lines that might represent some sort of fastener. The following photo I took inside the hold of the Kitamaebune Hakusan Maru shows staple-like iron fasteners holding planks together, but this is type of ship that would have appeared, some 600 years after the Kamakura period sea boat.
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More likely I think is the use of something like the dovetail fasteners illustrated in the following photo from Douglas Brooks’ blog entries during the building of a sabani in Okinawa back in 2009-2010. But, at the small scale of my model, I decided to omit this detail, as it would be both too difficult for me to make or even simulate, and it would also be nearly invisible.

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The next detail then, was to notch the upper bulwarks planking and add the transverse beams across the hull. These would extend far enough out from the hull to support a pair of outboard rails that run nearly the length of the boat. It didn’t take long to cut the notches and make the beams since they were all identical to one another.

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With the beams in place, a caprail was added, locking them down into place. The main section of the outer rails were added too, as well as the bow deck. At this time, I also corrected the piece that runs across the front of the bow. I originally had two pieces, the upper piece over lapping the lower, but replaced this assembly with a single bow piece, which seemed to be more correct according to the drawings.

One thing that seemed very odd was that the main museum models and the drawing showed a beam riding atop the bulwarks at the bow. The drawing and models show a forestay labeled a hazuo 筈緒. But, a forestay would exert an upward force on the beam, so it would have to be fastened down securely.

One drawing I’ve seen, shows the outer railing mentioned above extending all the way around the bow, and the beam fastened to it. Without this railing, I decided to add a below-deck beam, which this topside beam would be secured to with rope fastenings. This is something I’ve seen in other boats, so it seemed reasonable here. If you look closely at the bow deck, you’ll notice two square holes. It is through these that the rope fastenings pass.

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The next part of the build was easy, and involved planking the deck for the long deck house or yakata. I worked out the average width of the deck planks from the drawings and cut some strips of hinoki. These had to fit flush with the tops of the beams, which also meant that I had to adjust the widths of the planks so that an even number would fit between the beams. Of course, I also had to build a ledge for the ends of the planks to rest on.

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Next time, I’ll start on the completion of the stern and the construction of the deck houses and details.

 

Building the Kamakura Period Umi-Bune, Part 3

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The largest source of Kamakura period boat information appears to be in 13th century picture scrolls that appear in books and on the Internet, but I really know very little about the scrolls themselves. What they depict includes a lot of boats with hull designs very similar to the ship I’m modeling. These are semi-structured ships or junkozosen (準構造船) with dugout-style hull, which have been built up with hull planks. Most of those depicted are river boats, but some appear to be sea boats.

I recently found a great sketch of a large sea ship on a blog site. I believe this was scanned from one of Professor Ishii’s books, but it’s not one that I have.

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This image is very similar to a less detailed drawing I have in my books. The ship depicted here varies only slightly from my model in that this image shows a peaked roof called a kappa at the bow. It also has only a single rail outboard of the hull, but it extends all the way around the bow. It also may be a somewhat smaller ship, given there are only 4 rowing platforms on either side, where my model will have 6.

A couple things I like about this image in particular is that it shows a roof design on the main deck house that is clear and makes sense to me. Note the boards that make up the roof run along the length of the roof. The drawing I’ve been working off of, shows the boards running perpendicular to these – not that it’s wrong, but that it requires an underlying structure that’s different from what I would naturally build. Also the front of the house appears to have a simple roll-up screen, no door or solid panel.

Finally, the small structure at the stern clearly appears higher than the main deck house, with the stern seemingly rising up more sharply than the bow. This makes sense, as it would allow the boatman at the helm to be able to see forward. Not that it would matter when the ship is under sail, as the large straw mat sail would block the view anyway.

Finally, the stern deck seems to rest on top of the cross beams, perhaps also contributing to the stern structure’s height. This is one area that has been the most unclear to me in the whole project. On my own model, I will make certain assumptions and reconstruct the stern area in the most logical fashion to me. In future builds, I can make corrections if they are necessary.

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The next steps of my build went very quickly. I first painted the bottom using artist’s acrylics. I was originally thinking I’d just use a spray lacquer, but the soft layer of the acrylics helped out on working with the balsa hull cover. I had dropped the hull on the desk and, being balsa, the hull covering had a slight dent. So, I just poked a pinhole in the paint where the wood was dented, wet the wood through the pinhole, and the wood swelled back into shape. I believe the flexibility of the paint allowed it to stick well through the process and allowed the wood to easily come back to shape.

After the painting, I cut a paper pattern for the floor pieces that would fit atop the bow and stern blocks. I then glued up some planks, cut the completed sections to shape and added them to the model.

I decided to glue up the planks so that they would run longitudinally, or fore-and-aft fashioned. This might seem obvious to wester ship model builders, but I had to think about this. I’ve seen pictures that depict the planks running sideways, the way I’m planning to fit the deck planking. But, it seemed to me that such planking on the bottom of the boat would be weak, and this is a sea boat. So, I built these panels in the same fashion that the bottoms of other traditional boats are built.

FYI, I’m using a combination of some hinoki strips (Japanese cypress) and Port Orford cedar, which is often referred to as American hinoki because of its similarity to the aromatic Japanese wood. The hinoki strips are a Woody Joe product that a friend in Japan got for me. The Port Orford cedar was purchased from Bear Creek Lumber in Oregon. These are very light colored woods, so I treated them with a mixture of Transtint wood dye.

Next, I added the planks that make up the lower bulwarks. Since planking would have been edge fastened using nails into the log hull, I needed to simulate the mortises for the nails. At 1/50 scale, the simplest thing I could find was to use a stainless steel carving chisel I had on hand that I’d never used. The chisel has a wide flat blade, so I just ground off much of the edge, leaving a fine point. I purposely chose a wide chisel, as the wide blade was an easy visual guide to help me keep the point straight – a problem I encountered with another build.

[Note: I couldn’t find a photo of the tool, so I’ll have to post it later]

I tried to grind the chisel so that the new point would be centered, but I didn’t do a very good job and it ended up off-center. This turned out to be a good thing, as I used the width of the blade as a way to measure the spacing between mortises. If I went left-to-right, I had one spacing, and if I went right-to-left, I could get a different spacing.

I used a piece of tape as a guide to help me keep the mortises in a straight row, and just pressed the tip into the wood to make the impressions.

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Once the lower planks were in place, I then cut beams and glued them down to the top of the hull and began laying in the deck planking between the beams. I don’t know for sure if this is how it would have been done, but based on other models and on traditional Japanese boats I’ve studied, this seemed to make sense. Also, the result pretty well matched the drawing.

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You’ll notice the hole I cut into the hull. This is for the mast step. I’d forgotten to allow for this earlier, so I had to rather crudely cut the opening. But, the edges will be well hidden by deck planking as you’ll see in later photos.

You’ll notice also that the way I supported the deck planks. Because the planks are half the thickness of the deck beams, I added ledges to the longitudinal beams. This is something I got from building Woody Joe’s Higaki Kaisen kit. These deck boards were likely removable. I assume that the longitudinal beams might have also been removable, though a ship like this might have needed them in order to stiffen the hull from flexing with the waves.

But, a log hull is very solid, and the bulwarks planking would have also been rather thick, providing a lot of support for the hull (thick planking is a common feature of traditional Japanese boats). Also, the ship was mainly for traversing the inland seas.