A guy comes into the pawnshop, says he wants to sell a cannon.
I ask how big it is. He says it's in his truck, he'll go out and bring it in.
It looks like something that needs buying. I ask him what he wants for it.
He says he doesn't know, what do I think it's worth?
I don't have a lot of experience purchasing cannons, but have used $1/pound for buying anvils. So I offer that.
He says ok, and I get my digital fish scale. Soon I am $50 poorer (but a mortar richer).
I'm assuming it's a model of this.
The Dictator, used at the seige of Petersburg, VA.
It weighed about 17,000 pounds more than mine.
I see now how they 'aimed' the thing. The wheels and axle are eccentric. When firing, the wheels are off the wooden platform. It takes a lot of force to make it move on its base.
A stout pole in the end of the axle and moving it 180 degrees puts most of the weight on the wheels.
The pole would then be put in the holes of the wheel itself to turn the mortar. Then almost no effort is needed to move it.
For elevation the same pole could be used to pry the lugs on the breech up or down, the barrel fairly evenly balanced between the trunnions.
For now it just spends time on the hearth, until the next seige operation presents itself.
Jim