hmmmmmm. I feel like that's almost an impossible question to answer. it depends on so much - and the biggest thing it's dependent upon is what your enemy's bring and what your ally's bring.
if you're talking strictly taking down a ship, gatling/mortar is probably best, and that's probably most effective on pyras and junkers. when you throw in the skill of the person on the mortar, it's easier to hit from a front gun than a side, so probably pyra.
but if the enemy's bringing long-range weapons, that metamidion may not be effective at all; they may get disabled or fall before they ever get in range.
for longer range, hades can tear up a ship as well. I've seen hades/artemis and double hades done on varying ships; I'm not sure which build is better.
but this is strictly speaking to bring ships down. not every match is a DM, and sometimes, speaking of "most powerful" is in disabling power, not power to kill.
there are so many answers to this, and none of them are wrong. different ship builds are used to counter other ship builds, different ship builds compliment each other well. and some players function better on a particular ship or build better than another.
aaaaaand this sort of variety is one of the things I love about this game <3
