Utah cage mast diorama
Completed in February 2011.
For my next diorama project, I'm going to go back to the old pre-WWI US Navy to examine a little-remembered aspect of naval shipbuilding. While most warships for the last 100 years have had tall tubular masts of rolled steel or sheathed wood, for a short period from around 1910 to 1925 the US Navy experimented with a new style of mast that was a cylindrical lattice of metal tubes. Initial tests showed that this "cage mast" design would be stronger and lighter, and stand up to battle damage better, as well as serve as a more stable base for the spotting platforms that these old ships relied on. In practice, however, the cage masts turned out to have serious problems with sway and vibrating in bad weather and by the early 1920s most of them had been replaced with traditional solid metal tripod masts.
Amongst the warships that were built with cage masts as part of their original designs was the battleship USS Utah from 1911. What I'm going to attempt to model is the top 30 feet or so of the Utah's mainmast, showing the spotting tub and a section of the cage lattice below it, all the way down to the lateral yardarms.
This "spotting top" was an open station that usually held a number of range finding and observation equipment. In the days before radar, a warship had to visually see an opposing vessel, so the higher up the eyeballs the further away they could see the enemy. Also, the higher up, the better they could aim the guns, as accurate fire depended on being able to correct your aim based on where the previous shots landed. This was the cage mast's undoing, as they didn't provide stable enough platforms for the targeting equipment to function as needed.
In the picture of the Utah below, from 1911, note the cage masts and the round "tub" like structures on top...
As always, it all starts with a piece of paper and a pencil to draw out the basic plans. It's looking now like the conical structure will be 8 inches tall and 5 inches wide, with the yardarms extending out another 4 inches on either side for a total of 14 inches. Those numbers might (will) change as the build progresses, but it's a pretty good guess for now. Going to start with the cage mast portion, which will be a tapered cylinder 4 and a quarter inches tall, and 4 and a half inches wide at the bottom and tapering down to around 3 and a half inches at the top. I first built a form out of a scrap piece of foam board and stuck four dowel rods into holes drilled with my knife. I can then use these rods as the framework for the cage, supergluing the copper wire circles along the lengths. This, unsurprisingly, turned out to be a disaster and I had to scrap the whole thing.
Taking a new tact, I wandered around the house with my ruler until I happened upon an empty tub of cottage cheese, which turned out to be almost an exact match (though an inch shorter). With the tub as a form, I made a framework out of 5mm strips of cardstock, taped down and then held fast with Elmer's glue. This turned out awesome, once I had cut the tape with a knife and carefully shimmied it off.
Once I proved my method would work, I slipped the cage back on the tub and added more support strips, both diagonal and vertical, cross-hatched in a lattice pattern with great care and much glue. After it all had a chance to dry and set, I slipped the cottage cheese tub out again and taa-daa! we have a freestanding cone that's surprisingly strong. All of this, by the way, only used up half a sheet of card paper, cut into 5mm strips. Decided to hold off painting until I get more done. So next step is to build the solid sides of the "tub" out of cardstock. Hole-punched a line of drainage holes along the bottom, these were at about toe-level and kept the tub from filling up in rainstorms. Set and glued it on, securing the edge with a bit of tape. Then added a combing and some internal support strips.
The floor of the tub is cardstock with a square hatch cutout for the ladder. I also buttressed the underside of it with wooden popsicle sticks as I'm concerned about the weight that it will have to hold later.
On the "front" of the mast, facing the bow, is a long pole that serves as both a brace for a short horizontal yardarm and the support for a utility crane for raising and lowering stuff from the tub to the deck. Made with dowel rods and paper strips. The crane is a mixture of wooden parts and paper and cardboard. Next I made a windlass for the crane's cable, which will sit inside the tub. I'll use string for the actual cable, but not until everything is painted.
Painting time next, two coats of Medium Gray over all surfaces (boring, but accurate). Unexpected troubles arose when it became clear that the single-ply strips of cardstock deformed when the paint dried, forcing me to use more effort and glue than expected to straighten out entire sections. I probably should have expected this, but I forgot, it's been a while since I painted single layers of cardstock this way. Anyway, it's done and it looks ok, even if not especially so up close.
Next need some stuff inside the tub. Built two round soft-sided canvas bags, probably containing foul weather jackets, and a heavy, curved metal box, probably containing observation equipment such as binoculars and such). Made them all out of clay, painted a softer Steel Gray. Then wrapped brown string around the windlass and then up to the pulley on the crane and to the hook (also made out of clay), making a pretty good approximation of cable.
(ok, update, project cancelled due to accident damage! Parts salvaged, lessons learned, move along, nothing to see here...)
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