Anyway, the people mentioning how the Heavy Flak is useless at close range are tragically incorrect. Is it essentially a 50% decrease in DPS? Yes. It's
only 50%. It's still huge, and you have a much better hit rate. Even with a Field Gun, you'll be able to do competent damage unless your piloting is off.
Phoenix Claw is vital here to keep your turn speed up. If they try to circle, you can reverse rotation and bring your right side to bear, which should usually consist of close range weaponry; a carronade and a hwacha is an excellent combination, and makes you no slouch in close range scraps.
Let's not forget the Galleon is
ridiculously hard to kill. Provided sufficient engineering, you will stay in the air for a long time unless you're getting hit by three or more ships, or one of the two ships is a dual flak Galleon at range. When you're being piled on by enemies, your teammate has a great opportunity to get in and fight for free. One ship is seldom enough to kill a Galleon unless it's another Galleon with superior gunnery.
I feel heavy weapon balance (and thus, Galleon balance) is decent, because you have tradeoffs to make. Dual heavy flak gives you the best explosive DPS in the game, but makes you sub-optimal close. Putting a hwacha or carronade makes you sub-optimal at long range, but gives you versatility. Doing all close range (carronades and hwachas) is difficult to pull off given your poor maneuverability. And Lumberjacks... are just too weak to use on anything.