I'm a bit surprised at how long it seems to take to break a target dummy's hull - nine hits with heavy clip, and that's on a target that doesn't repair at all. Still, I really want to drag one of my usual groupmates on board the galleon and see how it cooperates with a harpoon shot. That ought to cause some...interesting physics. And double heavy Minotaur plus top-mounted flak cannon will probably be a pretty brutal kill-side, especially since the Mino negates the arming time problems by simply sending anyone who gets too close spinning off over the horizon. If anything's overpowered on this gun, it's the physics effects.
Anyway, I can see it working out alright on pretty much any Spire, and it pretty much is built for the Galleon (seriously, it's got side arcs and inclination that can probably hit someone behind you - so much for the classic blind spots!), but the 'fish pretty much needs to combo it with terrain to kill. For a Goldfish, I pretty much consider it a long-distance ram that you can follow up with the traditional sort when they slam into a mountain, which is useful but maybe not optimal. Of course, this is all theoretical stuff based on my trial runs in the offline practice mode, so I could be completely wrong about its role against a live and vaguely competent crew.