Now i know there is already a pirate battle idea, but i was thinking making another pirate battle where there are limited resources would be very intresting. Everyone starts with an empty inventory, the boat comes pre stocked with a few items, the most important is a redstone torch.
In the hull of each ship there is a chest where both ships are supplied with random helpful things, such as ender pearls to teleport to the other ship perhaps, or another torch so you can fire the cannons faster, or armor, or more bows, or things of this nature. The name of the game is basically resource and time management, learn when to fire and when to defend, or when to just murder the crew board and light their TNT on fire.

Jobs:
There are cannons on the walls of the boat loaded with repeaters loaded with fire charges, when you apply the torch to the right spot it fires one charge, then you remove the torch and replace to fire again, so you have a cannoneer in essence.
There is a bow, which you can use to slay the other crew members.
There is the task of putting out fires which are being created by the fire charges fired from the other boat

The center of each boat is a row of dynamite, the goal is to get that dynamite to light blowing the center of the boat apart.