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Skipray Blastboat!!!
That has been on my list. Ultimately I think it would share a LOT of characteristics with the YT-2400: a "weak" turret as a primary weapon, have a cannon upgrade slot (although it could introduce the HEAVY Ion Cannon), and probably some ordnance loads but may not have the crew slot.
Here's what would make the Skipray something different from what's already in the game: instead of a turret primary, it gets an ion primary . Those three big ion cannons are obviously its main weapons, after all.
I agree about the cannon being the actual primary weapon on the Skipray but when it comes to the game rules it would be so much easier to give it a turret primary and have the big Ion cannon be some kind of upgrade. Without that you're going to need rules text explaining the primary weapon or a title that provides that functionality but fills that possible design space.
Now if you're worried about the cannon being overpowered on something else give the Skipray two cannon slots and make the upgrade fill both of them. Now you only have to worry about Aggressors stealing the cannon.