Kronos Heavy Flamethrower:
Like the Dragon Tongue but with longer reload time, increased fire rate, smaller clip, and will push/turn your ship in the opposite direction as it fires.
The Minotaur can move the enemy ship, but I think we need a new gun that can move your own ship when you fire it.
It would be like a flamethrower hwacha and could primarily be balanced against the hwacha.
I think the idea behind heavy guns is that they try to reward skill more than light guns, so:
Be careful to avoid pushing yourself out of range by shooting it too early.
Fire it when your target is most vulnerable to a fire attack; quickly adding tons of fire stacks to things won't contribute if those things are about to break anyway, have been chemsprayed/heatsunk, or have already been broken (especially if they are about to be repaired). Firing too much of it at the wrong time is a wasted clip and a long reload. So while in some ways it is just a more powerful flamethrower, it has certain drawbacks that the flamethrower does not. The light flak and the heavy flak have a similar relationship.
Tartarus Light Grenade Launcher:
1 shot clip, decent muzzle speed, 900 meter range, 10 shell drop, Primary shatter (50), secondary flachette (270), 5 second arming time, 120 meter AOE
It if hits them (even before its arming time) it will deal primary damage first, and its secondary damage will delay and go off once its arming time ends. It can basically stick to them, and so the arming time isn't much of a disadvantage.. Unless they get too close to your ship so that the grenade hurts your balloon too! Or unless they skillfully use that time to prepare for the balloon damage!
It's an easier, immensely weaker lumberjack that is bad at close range for a different reason but opens up new strategies for the light ships. It's also more heavily dependent on special ammunition than the lumberjack, since it suffers no negative effects from using charged or lesmok and is balanced with these in mind.
Having it use flachette buckshots would be cool, but possibily difficult because they would have to originate at a strange location instead of from the gun itself.
I didn't talk about angles because I don't think either of these would have profound ones.
They should have better names too, I didn't put much thought into these.