Take a look at the second design, the gun is pointing diagonally.
Right, but I think my point still stands- the Mobula already fills the "all the guns point the same way" niche. I like your idea for a fast, slow-turning ship that specializes in gunning on the go, but I think having every weapon face one way will be far too restricting.
Every fight would involve you circle-strafing the enemy in a counter-clockwise direction; there would be no other tactic you could take, except with a sniper build that doesn't require much movement. The Mobula works because all the guns face forward, a natural direction to move.
This ship seems to be a blend of the Galleon's broadsides with the Squid's fast movement, which is great! What I mean was, to move the forward-left facing gun to face forward-right. You still have a blindspot behind and to the rear-right, but you're not quite so helpless. If you have to peel off an attack or something, or an enemy pops up in an unexpected area you can still offer some kind of resistance. Again, it also separates itself so that it's not just "The Mobula, but everything faces left!" (I'm not saying that's what you're saying, that's just what my guess for how it would turn out)
Designing new ships is tough- you have to make them unique enough so that they're not treading the same ground as existing ones, but also not so niche that they're only good for one thing. I can see this ship being good at a couple of different things- a fast-moving, hard hitting support ship (with a Hwacha/Light Carronade on the left, you could zoom in, pop their balloon and wreck their guns and then fly off while your teammate makes the kill), a finisher (ally breaks their hull, you zoom in and cap them off) or a long-range support (floating just out of the danger zone, circling around and picking off targets).