What we have here is a promotional video for a shipboard automatic mortar. Main difference between a mortar and a cannon is that the mortar barrel has a smooth bore, not a rifled one like cannons. Of course, our main battle tank the M1 Abrams is also a smooth bore, but that's on of account of it being such a bad-ass it don't need no steenking rifling. Mortars shoot shells with fins and at much lower velocity than a cannon. Cannons have more range. They are good for killing people and blowing things up in the next town. Mortars are for destroying the enemy who is just over the next hill.
So this thing can basically be used at low elevation like a tank for close in stuff, or elevated for over the hill stuff like a conventional mortar. They show this gun holding its heading while the boat goes through some gyrations, but you'll note that the water is smooth as glass. I wonder how well it would do when the water it gets a little rough.
Anyway, there was some discussion of where a boat like this might be useful, and AngryFinn mentions that it could be really useful in Finland if the Russkies ever come calling because
The Finnish Archipelago Sea is the Europe's largest archipelago area, and it has the largest amount of islands (40 000) in a one island group in the world.
Google Maps has changed and I haven't figured out how to embed a map, so we have a screen shot and a link. Map is about 200 miles across.
I've noticed that there were a bunch of islands in this area before, but I didn't realize there were 40,000 of the dang things, and there are going to be more or less in the future:
The islands began emerging from the sea shortly after the last ice age. Due to the post-glacial rebound the process is still going on, with new skerries and islands being slowly created and old ones enlarged or merged. The current rate of rebound is between 4 and 10 millimetres a year.So in ten years these rocks are going to be 2 to 4 inches higher. In a hundred years, assuming this rate doesn't change, and I doubt that it will, we're talking ice-age time-frames here. In a hundred years they are going to be two to four feet higher out of the water. Unless global warming catches on.