Protip #2: If your area is overtaken by Radiation, it will kill off all (most) sea life. So you can "win" a hunting mission without firing a shot!
I thought that killed randomspawns but not quest mobs and the like?
Anyway I play this game a lot and I've got more than a few completed subs in the submarine editor, though I haven't really released them. Here's the like single one that I've got published into the steam workshop. I call it the Shoe..
In comparison to other subs I think it's pretty small I think, and it's got a lot of quirks. The front is an unnecessarily huge crafting room - the front gun is an unreplaceable mining laser; it's really weak, so the unnecessarily huge crafting room is prone to flooding if you let it. From there you head through cargo to the central shaft, which is also kinda large and flood-vulnerable. I don't think there's a pump in there, either. To the right of the bottom floor is the also unnecessarily huge diving airlock. There's no manual door control, it has to be toggled open and closed from the Captain's seat, and when it's open it's so big that even with all the ballasts empty it makes the ship sink. To the left of the bottom-floor of the center shaft is the armory; it doesn't open from that side, but people in the armory can flip a lever to pop the door open and hand out weapons when needed. Top-left of the shaft is a tiny crammed-in couple of electrical junctions and then past that is a ballast tank. I don't think OSHA would approve of the placement. Left is medbay, then gunnery/helm, a couple central guns on the middle floor, the pilot seat under them next to the door into the armory. There's a switchboard that toggles fancy battlestation alarms and buzzers next to the periscopes controlling guns, to let people know which ones need to be manned. Left of the pilot's seat is the reactor; past that is a tiny rear gunnery cockpit thing. Left of gunnery, meanwhile, is the engine room with a buncha battery power arrays and a beat up bed. You can rip off the door controls in there, which makes it into a ghetto jail cell, and there's a nice window so people can see and scream about the horrible fish trying to eat their way in.
It's got strong gun coverage but default guns are all very jank. The front gun's weak, the top gun's a big rail cannon, which is a difficult weapon to use against small targets. The ass-gun is another modded turret - a surplus coilgun. Coilguns are kinda like the standard ship gun; surplus ones are crappy versions of them, meant almost exlusively to get upgraded later. the bottom gun's an autocannon, also a mod gun, but it's real good and is probably the only non-proglem weapon mounted.
Currently I've been working on a no-mods vanilla ship. I think I've figured out minisubs finally. The other noteworthy thing about it is that I've been trying to build a railgun not controlled by the normal periscope gun controllers. Instead it uses a nav terminal's sonar to (poorly) spot targets at range. One rail points straight forward, but a tight cluster of THREE sit pointing straight up, with a button to make them switch between straight up and 45 degrees forward.