Capture the flag? What are we, sand grunts? Nay! We shall have capture the balloon. All we need is working harpoon mechanics and two willing target dummies retextured as cargo balloons.
Resource race? Add more cargo balloons spawning in at set points. Win by dragging as much cargo back to your base as possible. Squids would have an advantage? Nay! With mass calculated in, Squids would be pulling pretty hard and thus slowed down, while Galleons would steam ahead without much bother, perhaps even towing two loads of cargo. Want to go faster? Hook two ships up to the same cargo balloon.
Hell, just for fun, leave the rusty mortars active. In Capture the Balloon, have them shoot at the enemy team (yes, even as they are being towed). If the towing ship is destroyed, the cargo balloon engages engines and starts flying back to base.
In resource Race, have them side with whoever has them harpooned. For extra bonus fun, swap out the rusty mortars for dilapidated mine launchers (they shoot old, weak mines with limp balloons that slowly sink to the ground and explode), or other random weaker versions of existing guns.