Since I am no where near finished on my current project, I am of course thinking about my next one I would really like to do an Arkansas Class Monitor in 1/96 for Battlestations. The biggest challenge is that hull height, keel to deck is 2". Add 1/2" of barbette and 1/2" of turret and that is all the space I have to work with. I am also kind of a scale nut, So I would prefer not to increase the draft of the hull or make a loswer section for the accumulator to fit an Indiana style cannon. I have heard whispers and vauge hints about a big gun design called a cannister gun, but have not been able to find enough information to have a grasp of how they operate. They seem to be shorter than an Indianna and are capable of rotating, so I am very intrigued. Could anyone point me in the right direction?
A canister cannon refers to the layout of the accumulator, valve, and magazine. The standard cannon has a relatively long and thin valve and accumulator installed at a right angle underneath the magazine. The canister cannon uses a short, fat accumulator, with the valve in line with the magazine instead of perpendicular. There are two different valve arrangements. The positive pressure cannon operates just like a regular cannon, with an MPA-5 or MPA-7 actuator pushing open a buna ball poppet valve to dumb the air and fire the cannon. The problem is that the air line to the actuator can interfere with rotation. If you go to the WWCC website and look for photos of John Fox's Dunkerque, he had two such canister cannons installed for several years. The other possible valve design is negative pressure. Air is applied to seal the cannon and allow the accumulator to charge, and is vented to open the buna ball poppet and fire the cannon. The design is more complex to machine and takes a bit more plumbing to get it to properly safe the guns without firing. On the plus side, it can reduce troubles with the air line to the actuator and also results in a cleaner air path, improving performance. I'm not too familiar with the dimensions, but I don't know that canister cannons save height. The main draw was they don't have a long accumulator sticking out from underneath the magazine and are (in theory) a better performing cannon. I'll see if Kotori can dig up the dimensions of some of the cannons we've seen and see if there's a workable solution out there. I have seen a low profile cannon built using the standard/Indiana/J.C. White cannon, but I don't remember the details. Knowing who built it, I suspect it made a lot of design sacrifices which reduced its reliability and effectiveness. Still, it might be a good starting place to improve upon. I'll get more details tomorrow.
Gascan hit most of the important points. While traditional "Indiana" style cannons look like a dessert plate on top of a sausage, Canister cannons look more like a dessert plate on top of a coffee cup. Canister cannons have great efficiency and take up very little footprint area inside a ship, which is why the people who can make them usually do. However, they also tend to be taller than their more traditional counterparts, because of the accumulator. Your design challenge is fascinating. Can you provide me more dimensional data? Specifically, what are the internal dimensions of your barbette? What diameter, and how much clearance do you need? I believe something similar to my laser-cut cannon may work, if you produce a shorter cannon base for it.
Hey Dustin, I've been working on designing turrets for my Takao. My Indiana style cannon is only 1-7/8" tall using a 1" diameter accumulator. You could make it even shorter by using a smaller diameter accumulator. I will be building both Indiana and canister turrets for my Takao. There's no room to use an Indiana style turret for the B turret.
I do not have exact dimensions for the barbette, as the only bit of plans I have are ribs at the moment. I have thought about doing an Indiana with the accumulator located remotely connected by correct ID pipe. I might break down and build a Sveirge class PDN for the extra room and secondaries. The Swedes were officially neutral, so that would give me an unaligned ship. All this assumes I can find some plans.
These site might interest you. http://www.coatneyhistory.com/drawings.htm http://www.coatneyhistory.com/Sverige.htm
