So, I am enjoying Spelljammer, and playing around with various ideas when I came up with one that might just break the game for combat.

Take 4 levels of Artificer with Battle Smith subclass. Make sure your Intelligence is your high stat. You want a 3 minimum. Infusions are Multishot and Homunculus Servant. Iron Defender as a subclass bonus.

You need 1 operational Ballista.

Infuse it with Multishot so it becomes a magical 1 Ballista that ignores loading. This takes the normal 3 actions needed to fire down to 2.

Give your iron Defender a standing order to defend you while in combat. This is permitted by most DMs. It's the same as teaching your pet a trick.

Use your bonus action each round to order your Homunculus Servant to aim. This takes the action needed to fire your Ballista to 1, just the firing action.

At level 4, take Sharpshooter. We now have no disadvantage outside of the first range, and we can drop the to hit by 5 to add 10 points of damage.

Battle Smith let's you add your intelligence to any magical weapon's damage. We aren't wielding the Ballista, just attacking with it, so we don't get it on the to hit bonus.

We already have a plus 1 from Multishot, so it's at 7, take the sharpshooter optional function to make this a 2 versus an average DC 15 ac for most ships, and you have a 40% chance to hit and get to fire every round of combat with a Magical Ballista that hits for 3d10 10 1 3 or more depending on the modifier. Minimum 17, non crit max of 44. Possible 74 on a crit. And there is no disadvantage for shooting outside of range.