Wild Arms 3

There are four functions the sandcraft has, each one run by one of your characters. Each particular function has certain stats that are based off the character running it (for example, the Deckmate's defense determines the defense of the sandcraft itself).

As for combat order, there aren't set turns like in normal combat. Characters with higher speed can actually attack several times before slower characters get even one turn.Think of it as being more like the battle system from FFX.

Now, each character can run one area of the ship. Each one has specific functions. They'll have two abilities that require (but don't consume) a certain amount of FP to use, just like Arcana spells, as well as a Force command that tends to be very useful. Also, all areas can choose to defend (increasing the sandcraft's defense until the character's turn comes up again) or to "wait", which will increase the Sandcraft's FP. Which reminds me, all four characters will use FP from the sandcraft's own FP gauge. Think of it as four characters sharing one gauge. Now, for individual areas:

Helmsman: This person moves the ship. The helmsman doesn't have any attack options. Instead, they can move the ship to the enemy's side (and then get behind them by moving again). Attacking from the side deals more damage, and from behind even more so. The helmsman can also use flares to reduce the enemy's evasion. Their force command will drop a flare, then move immediately to the enemy's backside, essentially performing three turns at once.

Harpooner: The harpooner, though seeming to be an attack role, is more support than anything, due to low damage output. They fire the sandcraft's harpoon into the enemy (dealing minor damage, even with the best harpoon), then can pull the enemy in with the harpoon (these two actions are separate, by the way). The gunner (described later) will deal more damage when the enemy is pulled in close. Note that whenever the enemy's turn comes up, the harpoon will come loose, but does not automatically retract. The harpooner retracts the harpoon by using the same command to pull enemies in. The harpooner's force command fires the harpoon, then immediately pulls the enemy in, essentially performing two turns at once. It can't be used if the harpoon isn't retracted, by the way.

Deckmate: Like the helmsman, this role has no attack options, but instead is more of a general purpose role. They can increase the speed of other units, reload ammo for the gunner, and their force command recovers the ship's HP.

Gunner: Possibly the most important member of the ship, the gunner is the ship's main source of damage. They can choose to fire a shot at the enemy, and also load elemental ammo to change the ship's attack to an elemental attack (this is usually a waste, though, as elemental ammo needs to be purchased, when all your fossils should be saved up for the best sandcraft gear, not to mention that simply blasting away is usually a better use for the gunner's turns). Note that the gun has a set amount of ammo, just like arms. When it runs out, the gunner can do nothing until the deckmate reloads the ammo. The gunner's force command fires every remaining round of ammo you have at the enemy. The more rounds you have, the more damage you get out of it. Early on, it's just a bit of extra damage, but with the best cannon, it becomes an instant OHKO to everything. Seriously, I don't think there's anything that can survive 8 rounds from the best cannon in the game.

One final note: the default assignments for sandcraft duties are Virginia as the helmsman, Jet as the harpooner, Gallows as the deckmate, and Clive as the gunner. You can switch duties around if you so desire, but the default setting is also the most sensible choice, as all the functions have characters with stats that seem built for that particular role (such as Clive having high attack for the Gunner).