Converting Trumpeter’s 1/144 SSN-21 Seawolf into the SSN-23 Jimmy Carter

By Chris Banyai-Riepl


The Seawolf name has graced two other boats before the latest version. The first Seawolf, SS-197, served during WW2 and managed to sink no less than 108,000 tons of shipping in 56 sorties. In 1944 the first Seawolf was mistaken for a Japanese submarine and was sunk by the USS Rowell in the autumn of that year. The second Seawolf was an early nuclear boat, SSN-575, commissioned in 1957. This Seawolf was unique in the US submarine fleet, as it was the only sub to have a reactor cooled by liquid sodium. While more efficient than the traditional water-cooled reactor, the exotic cooling method had plenty of maintenance issues. Still, the second Seawolf performed well when she worked, and became one of the Navy’s special project boats for many years. Interestingly, Lieutenant James Earl Carter was to be the Engineering Officer on the Seawolf before he was called home to run the family farm. The second Seawolf was decommissioned in 1987.

The current Seawolf, SSN-21, represents the first submarine designed from the ground up since the Skipjack class in the early 1960s. Designed as a jack-of-all-trades type of boat, the Seawolf is capable of a wide range of missions, including surveillance, intelligence collection, special warfare, covert cruise missile strike, mine warfare and anti-submarine and anti-surface ship warfare. As impressive as the Seawolf is, though, it came too late in life to survive long. The end of the Cold War left many people wondering whether the Seawolf class was an effective usage of funds. With the project eating up roughly 25% of the budget, the program quickly fell to the axe of budget accountants, with the final production capped at three boats. These budgetary issues eventually paid off, though, with the development of the Virginia class submarine, which employs much of the Seawolf’s technology, but on a smaller (and more affordable) scale. To help bridge the gap between the end of the Seawolf production and the production of the first Virginia class submarine, President Clinton endorsed the completion of the final Seawolf class submarine, SSN-23.

As the last Seawolf under construction, it was decided to further enhance the capabilities of the boat, in terms of covert operations. Previous special operation boats often had to carry equipment externally on the hull, both slowing the ship down and creating more detectable noise. For the SSN-23, this was solved by inserting a 100-foot plug behind the sail. Inside this plug, the pressure hull tapered down into a wasp-waist arrangement. This left the remaining area between the wasp waist and the outer hull open and flooded, capable of carrying large amounts of equipment without any negative impact to the acoustics or performance of the submarine. The result is a special operations boat with incredible performance and capabilities, easily unmatched by any submarine in the world.

The Kit

When I first reviewed the Trumpeter Seawolf back in 2005, I thought it would make for a nice weekend project. In fact, many of the buildups that followed the release proved that point. For some reason I held off on building it, though, as I wanted to do something a little different. At first, I thought I would just build SSN-22, the USS Connecticut. However, as these boats never carried hull numbers, there really is no way to tell the SSN-21 from the SSN-22. Then I came across a photo of the Jimmy Carter rolling out of its assembly building, prior to launching. The 100-foot plug was readily apparent, making this sub look quite a bit different from the standard Seawolf. With that, the decision was made to do a simple conversion into the SSN-23.

With that decision in hand, I moved on to the logistics of the conversion. Doing some quick dimension conversions, I discovered that 100 feet in 1/144 scale equals over eight inches. This would result in a finished model stretching over three feet long! Still, it is only three inches in diameter, so I figured it would fit nicely atop my bookcase, so I continued the preliminary work.

Note that I said that this kit was only three inches in diameter. Measuring showed that it was exactly three inches, so my first thought went towards using pipe. As on the real thing, this plug would be a constant diameter, so I headed down to the local hardware store and asked them to cut me an eight-inch section of three-inch pipe. The wall diameter was considerably thicker than the kit parts, but I figured I could just build up some layers in the kit parts to match, with the hopes that there would be enough there to produce a positive joint. Once home, I chopped the main hull in half and mated it up to my PVC “plug.” At this point I discovered something about PVC pipe. That three inches? That represents the INNER diameter, not outer. Oops. Of course, I had already cut the hull, so I was committed to the conversion. I just had to find another way to do it. So much for the easy, quick fix.

After talking with the other local modeler here, Gerry Nilles, he suggested that I simply build the plug from plastic. As a talented scratchbuilder, he saw no problem with this, and promptly handed me a section of 60 thou plastic card and a circle template. With these basic pieces, I stepped into the weird and wonderful world of scratchbuilding. Sure, I have scratched details in the past, but this marked my first attempt at a major structure. In one evening, I had all of the bulkheads cut, with their edges smoothed out. I notched these bulkheads on four sides for stringers, then turned to the problem of alignment.


Alignment is a big issue with this, as it would be all too easy to make a giant three-foot banana from this. In looking at the sub, though, I came across a great way to maintain alignment without a lot of effort. Along the starboard side of this sub is a large fairing for the towed sonar array. As luck would have it, this matched up perfectly to a piece of Evergreen styrene tubing, with the thickness of the tubing matching the thickness of the plastic. This meant that I could run another piece of rod inside the larger piece and use that to attach everything together and keep it all straight and true. With that arrangement set, I added a fifth notch into the bulkheads for the rod. Another advantage of this method is that I could precisely measure that fairing piece to the exact length of the plug, and therefore get the right spacing without lots of effort and measuring.


With all the bulkheads set up, and stringers set, I then turned to the skinning process. This had me scratching my head for a while, until my eyes lit upon the section of PVC pipe I bought. Three inches internal diameter. Matches the hull diameter. Hmmm. Gerry caught on to the idea immediately, and offered to boil up some water. The first thing I did was try it out with some small strips to go around the bulkheads. I figured that these would provide more surface area for attaching the skin, and give the final piece less chance of sagging between the bulkheads. These curved up nicely after heating them in the water and putting them in the tube, so I turned to the actual skin. The same process was used, and the results were, well, simply stunning. The skin curled into a perfect shape, matching up exactly to the kit pieces without any need for tweaking. In fact, it curled so well that gluing the piece in place was a bit of a challenge, as it hugged the bulkheads tightly! Still, it all went well and in the end, I had a plastic baseball bat.



With the conversion basically done, my attention turned to basic finishing and detailing. My first reaction after I started looking at the model is just how poor the Trumpeter kit was in terms of roundness. The upper and lower hull pieces are molded in thin plastic, and flex quite a bit. This makes it very difficult to make a round shape, and I expended quite a bit of filler to both blend in the plug and round out the hull. This is further exasperated by the fact that the bow and stern pieces also have atrocious fit. While the actual conversion took little more than a week, the process of getting the hull smoothed down and into some semblance of roundness took several months.

While I was working on that basic finishing, I started looking at the photos of the Jimmy Carter on the US Navy website. A nice thing about those photos are the high resolutions copies that are available. A thorough scouring of those photos revealed a rather large section on the plug that did not have any of the acoustic tiling on it. A prominent feature in that section was what appeared to be a hatch, with large rivets all along its edges. Also apparent was a large circular flat spot right behind the sail. There are some other small details, but I felt that these two were the most prominent and therefore what I should attempt to replicate in my model.

The circular flat spot was simple enough to do. I just cut out a piece of plastic card in the right diameter and glued it onto the hull. I then filled that in on the sides and sanded it smooth. The section of no tiling presented a bit of a challenge, though. Rather than cut into the plug, though, I glued strips of 10 thou card around the edges of the bare section, then filled up to the outside edges with a large area of filler to create a gentle rise up to that section. The result is what appears to be a recess in the hull, but is actually a small indent in a gentle rise. For the inside edges, I taped close to the edges of the 10 thou pieces, then applied filler. I sanded that down to get the sharp slope apparent in the photos. It is a subtle effect, but it works well enough.

For the hatch (which, after I had already finished it, I discovered was not a hatch, but a welded panel), I used a Waldron punch set and punched out a bunch of ‘rivets’. After carefully marking out their location, these were applied one at a time, over several days. I thought about applying them in one sitting, but these are really small (I used the smallest Waldron punch size) and my eyes were going cross-eyed pretty fast. While I had the punch set out, I also punched out some spurious details for inside the sail section, to break up the square monotony present there.

With everything looking halfway decent, I turned to painting. I don’t know how many times I primed this model, but I’m pretty sure it’s into double digits. When it came to actually painting it, though, it went fast. Contrary to popular thought, the Seawolf submarines, including the Jimmy Carter, are finished in overall black. No hull red for this guy! So, I picked up a bottle of Floquil Engine Black and a bottle of Floquil Weathered Black and tore into it. I painted the whole sub with the Engine Black, using the large jar with my Badger Universal airbrush. This really helped out a lot, as a three-foot+ model needs a lot of paint to cover it. Once that was dry, I masked off the hull bottom, sonar dome, and a black walkway along the top. Initially I was going to paint the rest with the Weathered Black, but that looked too gray to me, so it was cut 50% with more Engine Black. The result was much more subtle, and much more like the real thing. A gloss coat and it was ready for decals.


In looking at the kit decals, I could tell right away that they were pretty much unusable. For starters, they use the wrong typeface, employing what appears to be Helvetica or Arial instead of the standard Navy block-style lettering. Secondly, the size of the hull depth markings was quite a bit larger than they should have been. Thirdly, the white hatch markings were incorrect in layout and orientation. Finally, although there are not many markings on the Seawolf sub, there were several small markings missing. My only choice was to make up some new decals and have them printed up. Luckily, all the markings are white, so some Alps-printed decals worked perfectly. In addition to the white markings, I also printed up some hole markings for use on the plug, where there were some obvious flood holes. Our own Al Superczynski printed the decals up, ever ready to help out with projects like this (another reason in a very long list of why he’ll be missed), and for the most part they went down quite well. I did have some problems with the fin markings, though, mainly from my incorrect measuring. A quick slice with a scalpel fixed that, though.


With the decals on, this boat was really looking like a real submarine. I turned my attention to the final details. This is basically restricted to the periscopes and the screw assembly. Speaking of which, I must mention the problems of building a model this big. During assembly and painting, I managed to knock off the propulsion fin piece no less than eight times. While working on the front end, the back end would be swinging around and something that I thought was far enough away would connect with the back of the sub and ‘ping!’, away the piece would go. Eventually I got the hang of it, though, and managed to keep that piece attached once the decals were on.

While on the subject of the back end, I decided to paint the screw brass. After doing a bit of research, though, I discovered that it is more likely that these blades would be black or gray, as they apparently are of composite construction. Also, although I have no verifiable evidence showing this, I believe that the screw should actually be between the two sets of fins inside the duct. I was not about to attempt that piece of work, though, and the brass adds a bit of color to what is a pretty bland submarine. With regards to propulsion, I also left off the auxiliary propulsion devices found at the bow and stern. The Jimmy Carter has small propulsion units located in those places to assist in holding position near the sea floor. While I managed to discern the fore mount from the photos at the Navy site, I have no idea how these propulsion units look (are they shrouded like the main unit, or are they simple screws on a bullet fairing?) so I am going to do some additional research before attempting to add those. I did note that, at least on the fore mount, the propulsion unit is offset to port, for those who want to add these to their Carter conversion.

While still at the stern, I made a small modification to the vertical fin, adding a small extension for the tail light. The actual light came from a CMK set of navigation lights. That small detail really improves the look of the fin, I think. Since I added the light at the back end, I had to do the same on the front, and that involved a bit more work. The light pole in the kit is just a solid cylinder of plastic. I cut that off, used the Waldron punch set to punch out a disk for the top, and added three pieces of rod to complete the light housing. Again, the red light came from that same CMK set (I know, it should be amber, but I didn’t have any amber lights). This was a quick modification, but it really improved the look of the sail. For the other scopes and such, instead of using the kit decals I just painted all the spots on, which gave a much better look than the decals portrayed.

With those last little twigs atop the sail, the Carter was basically finished. It definitely is a bookcase model, easily filling out the top of my bookcase. Although my initial thoughts were to have the sub finished in a semi-gloss, the more I think about it, the more I think I’ll coat it with a flat coat. A duller finish will probably look a bit better. Sitting this next to my ICM Type XXIII submarine, also in 1/144, the size of the Jimmy Carter is truly impressive. I am definitely hooked on 1/144 scale for submarines now, and I am looking forward to my next subs, which will include several scratchbuilding projects. An Ohio-class submarine would only be marginally longer than the Carter, and there IS more space on the top of that bookshelf….

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