Building the Kanrin Maru – Japan’s First Screw Steamer – Part 3

Notice anything special about that photo of the fully planked hull in my last post? If you look closely, you may notice that the center section of some of the bulkheads are missing. If you’ve followed any of my wooden ship model building, you’d probably be aware that I can’t leave kits well enough alone. One of the things I’ve always liked to do is to add a hint of an interior. Nothing blatant, just a hint to create something of an image in the observer’s imagination.

Arrows showing where bulkhead sections were removed

I’ve discovered that I don’t like building full interiors and I don’t like lighting a model’s interior. That’s too blatant and too showy for me. I want the observer to look at the model and discover an open door and to catch a glimpse of more detail without actually being able to see beyond it.

You’ll notice in the photo below where I’ve started to make my modifications.I figured I might leave the aft companionway doors open, and have clear skylights, giving a glimpse of the lower deck. So, I cut away the centers of a couple bulkheads, painted the interior bulkheads white, planked a some small floor pieces, and inserted them into place.

Now, to be clear, I went back and forth quite a bit on how much detail to include on the model’s interior. In this case, I decided that all I really want to do is to have some planked deck space down below the hatchways and companionways. For the planking of the lower deck pieces, I used some 3/32″ wide strips of South American boxwood – the same as I will use on the main deck.

Section of interior deck in place. Note the cutout for the mizzen mast.

You’ll also notice here, my second modification, where I began to fill the spaces between the bulkhead extensions with sheet basswood to make it thicker and stronger. The same was done around the transom, which in the kit, is a very thin and rather fragile piece, but a perfectly shaped laser-cut piece.

I mentioned in my earlier post about researching the Kanrin Maru, that I found the bulwarks and caprail shape to be very strange in this kit, and it took me quite some time to figure out what was going on.

First, note that the kit instructions have you plank the inner bulwarks, but not at the bow or the stern.

Kanrin Maru bulwarks planking from the kit instructions.

Next item to note is the shape of the caprail. Below is a small section of the kit plans, showing the caprail as provided in the Woody Joe kit. Note where I’ve circled, where the width of the caprail changes. The red arrows indicate the ends of the kit’s interior bulwarks planking.

If the image is too small for you to see, here’s a close-up of the stern section.

Here you can clearly see that the caprail is thinner at the stern and bow. I’ve never seen this before and I found it very puzzling. Did the bulwarks planking have something to do with this? Or was this a mistake or maybe just some bit of fancy work on the part of the Dutch builders? It wasn’t until I had received and studied the plans I’d ordered from the Dutch maritime museum that it started to make sense.

First off, the changing width of the caprail is verified. But, in addition, it starts to become apparent that there is indeed a reason for this curious feature.

Below, I’ve zoomed in on one section of the image and added further annotations. The changing width of the caprail is clearly visible, but note the timber heads which frame the gunports. I’ve marked these with red arrows. As you can see in the image below, the leftmost timber head isn’t as thick as the others. This thinner timber head is located where the caprail at the stern becomes thinner. All the other timer heads shown are thick where the caprail is thick.

So, that explains why the caprail width changes – the bulwarks itself changes width. But, that leaves the whole other question as to why the bulwarks are wider amidships? Is it just maybe armor plating?

Looking around further on the same drawing, one discoveres a set of stanchions between the gun ports. Also, there are dashed lines that clearly represent the outlines of bulwarks planking. I’ve marked the stanchions with blue arrows. Another section of the plans shows a cross section view amidships that includes the bulwarks, and this clears up the story.

From this, it is clear that the wide portion of the bulwarks is really a hammock rail with a covering of thin planks. It’s interesting that the bulwarks on a ship armed with up to 12 cannons would be so insignificant. The thin planks might stop musket fire, but I doubt it would have any affect on cannon fire. At least, not unless the interior space is filled with something solid.

As for the model, this also tells me that the inner bulwarks should probably be uniformly planked, and that the widened part of the bulwarks is on out outer bulwarks.

Back to the Build

For my build, I went ahead and added the filler between the kit’s bulkhead extensions. Looking back, I should have used thicker wood, or used a second layer, as the bulwarks on my model are somewhat thin. But, once the cap rail is in place, it will be hard to tell.

Filler between the bulkhead extensions. Also, sheer molding in place.

At the same time, I added the sheer moulding as provided in the kit. The stern will be done separately in order to get around the curve properly. Also done at this time is the sternpost framing, which is provided as a single piece in the kit. I used this part as is.

Next, I decided to tackle the thick section of the  bulwarks. The area of the section is the entire bulwarks between the fore and aft gunports, so it was easy to simply use a thick piece of wood glued to the outer bulwarks. In the photo below, you can see where I marked out the gunport locations. I also sanded down the inner bulwarks, so that the kit’s bulkhead extensions of the filler wood I added were flush.

I cut out the gunports, but left enough room to add my own gunport framing, following the Dutch plans as my guide. Interestingly, these timber are rounded on the outer face. This leaves me thinking that, like shown in the kit, these did not have traditional gunport lids. So, they were either simply open, or perhaps there was some kind of panel that could be fitted from the inside to close them up. Photos of the Tokyo Maritime Science Museum shows open gunports. So, I’ll just simplify matters by keeping to the kit and the Tokyo model with open gunports.

I had to cut the gunports a little wide, to make room for the frames. Below, you can see I basically shaped a strip for the frame pieces using a router bit, then sliced off pieces of appropriate length.

Now, here’s where I made an error in judgement that I just lived with. At this stage, I should have gone ahead and planking the inner bulwarks. Instead, I cut these gunport frames and put them into place. the result is that the inboard edge of these frames are planked over. But, as you can see in the plan view above, the frames should be flush with the planking. I didn’t think about this until later and decided not to redo the work I did.

The pieces were glued into place. You’ll note that there is a slight lip on the front side. Perhaps this forms a seat for gunport lids. In the image below, you can also see that I added the kit provided deck.

The inner side of the bulwarks. The thin section is really too thin, even after I plank the inner bulwarks later. I added the waterways strip here. It was my intention to then start planking, but I change course and decided to create another thin plywood sub-deck, which I would plank and install on the kit deck.

In my next post, I’ll get to some hull details and planking of the deck.

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