This is another idea I have, But it's a simple single weapon. I know shotguns are a thing as "grapeshot" cannons. But this would be a shotgun you place on your deck with a 360° firing arc. Does no damage to anything metal or concrete and dose some small damage if close to wood. The main purpose of the weapon is to shoot boarding troops (enemy) on friendly nearby ships or the ship it is on, before they get in via the supply hatch. And also could maybe pop a round or two as the infantry are falling onto the ship. Can also be a counterpart to those small bee's or mechanical bee's the hives produce that are quite annoying. Just a small idea that could provide some nice counterparts to a very annoying attack enemies can and will pull off on you.
My poor hussars die fast enough as it is
What I do is make specialized ships, then you don't have to worry about cramming all different kinds of functionality into every ship and then each become efficient doing what they're made for.
Big ships are targeted first, so make them into tanks.
Medium ships aren't a priority target so lose the armor and add extra cannons for a Ship vs Ship variant or lots of rifles and maybe a gat and some flak for taking out all those dragoons or bees.
Small ships -- cannon fodder/support
one or two medium ships with mostly rifles and flak easily kill the lil' troops
Thanks for the advice. I don't have much experience with the game. This weapon idea is also for if you cant have another ship or your own ship with rifles shoot them off. I've encountered it before where a lot of my fleet is downed and the final ship(s) begin to get boarded w/o any rifle support.
When I raid those things I honestly only use 3 ships;
2 of them have 2 top mounted flak guns and about 4 rifles each then I have one larger fast ship that I use as a lure and just move it when they get too close
I had a similar, slightly simpler, idea for a mod. I hope to make it one day but if anyone takes a fancy to it feel free to knock it up!
Have a heavy cannon weapon which fires very slowly, but which fires mechanical spiders. The wolfram tipped shells roll % to pierce the target tile's armour and if successful inserts a mechanical spider into the enemy ship.
Deck shotguns would most likely be too specialized/niche for the game. And yes, it would probably be overpowered against Flying Troops.
Deck shotguns, as you describe them, would devalue the positioning that a good rifle-team or other anti-troop weapon needs.