May 23, 2018
The next step is to get the bulkheads installed.
In a plank-on-bulkhead build, the bulkheads are solid pieces (usually laser-cut) that form the ‘ribs’ of the ship. They install perpendicular to the keel. Each bulkhead is specifically sized and shaped to match the shape of the hull at a specific point, so each bulkhead goes into a specific location.
The Model Shipways Fair American kit contains 16 bulkheads, numbered from 1 to 16 running from the bow to the stern.
The bulkheads are laser cut, so when they are removed from their sheet they have a lot of laser char. This dark stuff is the result of the laser cutting process. Normally, you’d sand all this completely off before using a laser cut part. For the bulkheads, I’m not going that far.
Once the bulkheads are installed, I’ll need to fair the hull. Fairing the hull is the process of sanding the edges of the bulkheads to form a smooth line. Having a little bit of laser char left on the bulkheads gives me something to indicate if enough sanding has been done. (If I can still see laser char after fairing, then that part of the edge didn’t get touched during the sanding process.)
So, rather than sand all the char off the bulkheads in advance, I’m going to leave a little on there. I’ll just sand enough off to keep my fingers from getting dirty as I work with the bulkheads.
Once that’s done, I did a dry-fit of the bulkheads. Nothing gets glued in at this point. I’m simply test-fitting each bulkhead to make sure it fits correctly. Most of the bulkheads required a little work. Many of the slots in the keel were too tight, and had to be sanded a little bit. You want the fit to be snug, but not tight.
I decided to do some work on the deck lines before I glued in the bulkheads. Just like the outer hull edges, the edges that will form the deck of the ship need to be faired. These slope down as they go outboard to the bulwarks, and the deck also has a curve to it, so the bulkheads need to be faired from bow to stern.
It is easier to do this before the bulkheads are glued in. This allowed me to see what needed to be adjusted, pull the bulkhead out, sand it, and test it again.
Once this was complete, the tops of the bulkheads lined up perfectly with the keel and had a smooth line in each direction.
Bulkheads are glued in one at a time using normal wood glue. The critical detail here is to get the bulkheads perfectly squared up. Every model ship builder has their own tricks for this. I’ve seen lots of people use Lego bricks.
I happen to have some machined steel right angle brackets lying around, so I used those.
This right angle brackets were part of a set I bought at MicroMark years ago. They are designed to be pinned down to a build board and hold a piece at a 90 degree angle. I used them in combination with some normal office binder clips.
I used two right angle brackets per bulkhead. Since I had several, I was able to glue two bulkheads at a time, working out from the center.
Glue was applied to the bulkhead and the keel slot. The bulkhead was then seated in the keel and clamped in place with the brackets. I gave each bulkhead 20-30 minutes for the glue to set before moving on.
On my Bluenose build, I added some support struts between the bulkheads to make everything a little more sturdy. I’ve decided not to do that this time. The bulkheads seem pretty sturdy, and I found that the struts get in the way of clamps during hull planking.
Once all the bulkheads were installed, it was time to fair the hull.
Fairing the hull is a critical step because it creates the lines and curves of the hull. The bulkheads give you the general shape, but the outside edges of the bulkheads are flat. When you start to plank the hull, the planks won’t lie flat against the bulkheads. Each bulkhead’s edge needs to be beveled so it creates a smooth line to the next one.
The normal way to do this is to simply sand the bulkheads using a long sanding block that spans multiple bulkheads. That’s what I’ve always seen people do, and its what I did on my Bluenose build.
The Model Shipways Fair American plans and instructions recommend doing it differently. The plans indicate the amount of bevel for each bulkhead, and suggest beveling them individually by carving. I considered this, but I don’t trust that those bevels would end up correct. I decided to ignore the plans and do it the normal way.
I used a sanding block with 60 grit sandpaper. Most modelers will use a finer sandpaper, but historically I’ve had problems with not sanding enough during fairing, so I’m going to use something coarser that will remove more material.
I started at the bow and worked my way down one side. This is just a first pass, kind of ‘roughing in’ the fairing. I’ll do a final pass right before I start planking, after I get the filler blocks and transom framing in. The general process was just like what I did for my Bluenose build.
When the bulkheads are beveled, you can see that the tops are thinner, and both the inside and outside edges are angled.
The process was then repeated for the other side. I’ll do another pass a little later in the build.
With the hull roughly faired, the next step is to make and install the ‘filler blocks’ at the bow and stern.