Takom Iowa Class Mark 7, 16"50Cal Turret with Full Interior Start-to-Finish

This is a monster project that I’ve been wanting to do for years. The market had to catch up to me with the issuing of an Iowa Class 16" turret. I just viewed a box review to see what was in the kit and get a quick fix on just what I would have to make from scratch. I’m sure someone, somewhere has done this before, but I’ve never seen it.

This is a screen print of what I saw.

Behind the blast bags is… nothing. That means the entire gun from the exposed part of the slide reward needs to be created along with everything else. My plan is to do the gun house interior completely including guns, gun rooms, control space with equipment, manual trainer’s and pointer’s stations, the big rangefinder, etc, down to the 2nd deck below; the electric deck. This is the rotating part of the turret.

I already started, assuming correctly, that nothing would be in side. I started with the gun lugs, and am drawing the entire rear half of the guns. I am drawing all of this apparatus on SketchUp and then will 3D Print and scratch build all the rest.

Here’s the gun lugs.

Also, I will have to thicken all the walls with material to simulate the turret armor. I have pretty good references for all of this, but no actual dimensioned blue prints. The curator of the USS New Jersey Museum Ship sent me the actual dimensions of the rear face of the gun. With SketchUp if I can get one good measurement I can scale from that. So here’s the work on the breach end.

There are 20 threads in every segment of the step-thread breach. While I can make them and probably print them, I don’t know if you’ll see them in 1:72. It may not be worth effort.

This is going to be a massive project and will take a long time. I may not work on it continuously the whole time, but as many of you who’ve followed my other builds on this forum and other forums, I usually finish what I start.

While My initial plan is to build the gun house down to the electric deck that lies below, I’m not particularly interested in doing the projectile and powder flats, since there’s really nothing going on. The projectile and powder lifts follow a tricky path and might present distinct challenges.

The guns are traversed by two very large pinion gears driven by hydraulic servo motors onto a massive ring gear that runs around the barbette’s circumference. This ring lies well below the deck level. Riding above the ring is the roller track with a series of conical roller bearings that support the rotating structure and let it rotate smoothly with limited friction.

Additiionally, elevation is accomplished by a very long and robust roller screw that is raised and lowered by a hydraulic ball nut that surrounds it. It’s a very smooth, precise and sophisticated way to raise and lower the massive gun with little or no backlash. This compares to the pinion and sector that found on traditional artillery pieces.

All of this equipement is energized by hydraulic servo systems with and A-end pumps powered by electric motors, and the B-end hydraulic motors. These can be modeled reasonably in this scale.

Notice in the above that there were duplicate sets of manual pointing and training stations on both sides of the turret. It’s what accounted for the two little housings that project out of the foreward sides of the turret. There were many ways the turrets could be aimed and fired, starting with the main radar gun directors high up in the towers. These were redundant since either director could control all three turrets. Then there was the main range finders in each turret that could also control the other two if the main directors were out of commission. Finally there were these manual stations that could aim each gun old school. These ships were meant to fight and the redundancies made sure they could under battle conditoins. It must have been weird sitting way up in those little spaces while these monsters were roaring in the room next to yours. Also, the guns were operated by handwheels not much different than those that controlled the 40mm batteries. Imagine the mechanical advantage needed to rotate a 10" wheel and move a 2,500 ton structure.

Drawing continues. I finally figured out how to shape the slide casting (forgings?). It was hard to figure just what the shapes really were. With that done, I was able to get the basics of the back end roughed out. There’s still a bunch of finer details needed to get it just right. But the hard stuff on this major component is complete.

I fit the guns into the gun lugs on the turret that I drew. I don’t actually have to print the turret since it’s really the only thing that’s in the kit. But I wanted to get an idea if my scale was right. The guns dropped into the trunions perfectly so I’m comfortable with the widths. Remember: If it fits in the drawing, the printed parts will be exactly the same.

I elevated them to make the cutouts by interfacing the turret front face with the gun barrels in both depressed and 45 degree elevation and then cut out the marked areas.

I’m really looking forward to doing the detail work around the breach. Even though the gun house is in the Takom kit, I had to draw all of the gun house walls so I can fit all the apparatus into them. I’m actually going to model the rotating portion of the #1 turret. What’s going on below is also a major amount of work.

My printer is big enough to print the breach end from the trunion to the yoke as a single piece.

And now for some news: The curator of the USS New Jersey Museum Ship said they would display the model when it’s complete. He also granted my wish to see parts of the turret that are not open to the public for purposes of creating a better model. These would include the electric deck itself and those little manual control compartments that flank both turret side walls.


Oh man… gonna have to get me some court side seats for this one. :popcorn::beer:

Interesting build, subscribed :+1:

I hope I don’t disappoint. For the last 10 years, each project I’ve chosen, whether just scale modeling or for the trains, has continued to press the envelope. This is no exception. As I’ve gained more confidence in drawing complex objects in SketchUp and getting my printer to do my bidding, I’ve been able to do more stuff. I’ve been wanting to do this turret for years, but the tech wasn’t available until just recently, and I’m still healthy enough to accept the challenge. I heading to 77 so there is a limit out there somewhere.


This will be impressive :+1:

This is epic stuff- can’t wait to see how it shapes up.

Great project! Really impressive! Yes, 3D printing enables now modellers to build things you could have dreamed of only in the past - if you have mastered the art of 3D programming succesfully.

Wish you good health, good luck and tons of fun! (If you prefer short or long tons is up to you :slightly_smiling_face: ).
Kind regards

  • dutik

Really looking forward to following along, you’re certainly off to a strong start by contacting the curator. I live not far from the ship & have toured it quite a few times, it’s a seriously impressive sight.

Let me put some tea on, can’t wait to see what you do with this project!


Following with great interest. My father was a loftsman in the Philadelphia Naval Shipyard during WWII and did much development work for the New Jersey . He often told of the painstaking work involved in the seams for the chutes that carried the powder bags for the sixteen inch rifles . The seams had to be flawless lest they tear a bag and leak black powder everywhere. I still have his mold loft books .


Wow ! Did you father design molds or fabricate patterns ? I’m not familiar with the term loftsman. Yes the powder elevator chutes are all nonsparking bronze.

A loftsman lays down the lines of the ship full size on the floor of the mold loft . This was a large clear span room over existing shops - an actual loft , hence the term .
Molds were not the type people generally think of - a cavity or form that material is poured into to create an object - but a wooden cross section of the vessel or a component .
My dad was largely involved with developing the wooden bucks for what were referred to as “ furnace plates “ .
These were the sections of the hull plating that had complex compound curvature and had to be heated in a furnace (hence the name )and formed over the wooden bucks .
Both my father and grandfather were master wooden boat builders. While at the shipyard my dad divided his time between the mold loft and the small boat shop where all the ship’s small boats were built - while at the small boat shop a brand new motor launch came in for repair . This launch had been on a cradle on the the deck of the New Jersey during sea trials as the davits were still being fitted out . It happened to be in the vicinity of the muzzle of one of the 16” rifles during firing exercise.
The concussion from the muzzle blast ruptured every tank on the launch and peeled back the planking from the stem !
To put the power of these guns in perspective an AP shell weighed more than a VW Beetle . Imagine throwing a Volkswagen 23 miles …


LOL, I know several VW owners that have wanted to throw their VW even further than that after getting repair estimates :rofl: :sweat_smile:


The skills required to build ships like these is simply awe inspiring. Modelers tend to want to make the hull plating very exaggerated. In reality, the joints were quite smooth and at 1:350 barely visible. Another way to look at the power of the guns…

The pressure in the combustion zone reached above 40,000psi. The force on the back end of the projectile was over 8,000,000 pounds. That’s how you get a 2,700 object moving at 2,900 feet per second. The Iowa guns were 8 feet longer than their predecessors. This extra length equated to a longer time for this pressure to be exerted on the projectile and gave it longer range.

Working with the guys in the SketchUp forum I finally got the geometry correct on the gun slide. And I did a test fit on my printer and I can get the entire slide/breech component on the printer as a single part.

I then combined these parts and tried the whole assembly on my printer. It does fit, barely, but it does. The overhanging raft does not matter, it just won’t print there. The orientation keeps all the supports off that all-important back end. The rest of the gun, frankly, will be very had to see since it’s flanked by the gun room bulkheads. I could make one more gun for display outside the turret, but that would mean another metal barrel or I could use the plastic one for that. It’s just a matter of printing more parts. Once I have good, accurate and corrected drawings, I can make a million of them.

The guns load at the 5° elevated position so I adjusted the loaders foot rest up 5° so it would level when the gun was at loading elevation.

The curator and I messaged again today. He asked if I was going to do a WW2 or modernized turret? In the 1980s modernization, the range finders were removed from the #1 turrets. They tended to get wet in heavy seas, and when they had the opportunity, they removed them. Since the Takom kit does have the range finder “ears” sticking out, I will do most of my visit at turret #2 which still has this large piece of equipment. Turret #2 is one deck higher than the other two. The difference below decks is one more projectile handling flat. I’m not modeling that deeply so it won’t matter.


Continue to collect more pictures with details including the bolt patterns on the back counterweight and the top of the gun which I didn’t have good information on.

Here’s a great picture of just the slide isolated from the ship and the gun. I have to add that array of round rods that appear to wrap around the recoil cylinder on the bottom.

This picture shows a good view of the spanning tray and the projectile tray’s base.

Lastly, here’s the gun well lit showing the top surface.


Notice how little clearance between the gun and the side bulkheads. It’s why I have to come up with a scheme to show all the details on the sides and bottom of the guns. I will probably make either a cutaway or use acrylic walls in strategic locations.


Really fascinating stuff here - thanks for sharing!

Fascinating indeed! Following with interest! :slightly_smiling_face:

Well, I’d say your work is extraordinary but I think this expression falls short. I can’t wait to see what you do next.

Thank you!
It took a lot of hours of work, but I have the actual gun fully detailed. I probably spent 4 hours just on the breech details and getting the hinging and counter-balance system arranged in correct engineering.

I created two versions: breech closed and breech open. The handles and cams are in the correct position for each mode. The first two images are screen prints from SketchUp and the second two are Podium Rendering Engine photo-realistic outputs. Notice that the areas that are black show up as polished chrome on the renderings.

While the drawing was challenging just in the details, what made it more so was ensuring that every part was a complete solid, no backwards faces, and all parts were fully attached to the model in enough places so the print would be stable in the 1:72 scale. I want to print the entire receiver is as few pieces as possible. I think I’ll print the breech assembly in the open position as a separate parts. All the rest will fit on my printer as I showed earlier in thread.

There are left- and right-hand guns since the powder hoists come up the central column of the turret. The port and center gun have their hoists back-to-back so they have their powder hoist doors on opposite walls meaning the guns are loaded from two different sides. The starboard gun loads on the right side with the powder door on its left.

I still don’t have my hands on the kit or the barrels. Without them I can’t get too far into the weeds of the internal structure. I know that the guns are right. I will start designing the hardware in the gun rooms themselves including the rammer (which extends into the officer compartment) and the projectile cradle and the spanning tray. Getting the guns right was the centerpiece of this whole undertaking. And in doing so gives me a boost in confidence to do the rest.


Work continues…

Rammer detailing is almost done. Got some great references for the cradle and spanning tray which will be up next

Got a good start on all the decking below the turret. Right now I’ve inadvertantly drawn down to the 2nd projectile flat. I may not go down that far. But here it is with the roller track in place. The turret and machinery spaces rotate with the turret and are supported by the rollers. The two projectile flats below them only have a rotating ring that moves with the turret so the projectile hoists would keep in line with their respective guns. The center column rotates which has the powder hoist chases. These go up the center column as clearly seen in this image from the Summerall Missouri Book.

The humans in the picture show the size of the ring gear. You can see the rollers under the tarpaulin. The powder hoist trunks are in the central column. The shell hoists are not installed in this picture. The heavy wedges lying against the walls are the clamps that go under the ring gear that prevents the turret from ever falling off the ship (as if that could happen).

Here’s what I’ve got so far. The shells are to scale. The gaps between the stationary and rotating parts is exaggerated in my version. I will adjust all this when actually building the model. The big parts will be made “old school” with styrene and acrylic sheet. I will print the tapered rollers though. The ring gear will go around the upper-inner perimeter. That will be printed in segments just like the real deal due to size limitations of my printer.

A lot of the round parts could be laser cut… either out of clear acrylic or MDF. I have access to U 0f L’s Maker’s space and they have terrific laser cutters for public use. It’s been closed due to the latest COVID surge, but that will end and I’ll be taking advantage of it for this and other projects in the works.