I know this guide is old, but I do not agree with the loadout presented. I also recommend giving multiple loadouts and explain them instead of expecting to give just one cookie cutter. With the layout you present you are severely lacking in explosive damage. You have put 2 shotguns on the ship and one gatling, that means the primary form of damage is a gigantic amount of flachette + some piercing. The heavy carronade can destroy a hull on its own, so rather than putting on a chaingun, I recommend putting on an artemis, flak or mortar depending on what your priorities are. At the same time, the light carronade doesn't really add to the goldfish' abilities, so I would put a flare, minelauncher or flamethrower on it.
Alternative builds ->
Front: Hwacha,
Port: utility weapon/Carronade
Starboard: Chaingun/Carronade
Front: Lumberjack
Port: Carronade
Starboard: Mortar
Front: Flak
Port: Carronade
Starboard: utility weapon/Mortar