You have decided to assault a port. This will result in a battle between your crew and the enemy guard force. At it's core, this is a series of competitive dice rolls, but the battle goes through a number of phases in which you will be able to make a series of decisions.
At the start of the battle, you get to chose what the purpose of your attack will be. Your options are:
Having chosen your purpose, you then get to choose what method you will employ to carry out your mission. Your options are:
Once you have chosen your goal and tactic, the first round of the battle is fought. Each side scores a number of "hits" on the other side (which results in casaulties). If either side scores double as many hits as the other, the losing side is instantly routed. Your chances of scoring hits are improved with a high Fencing value (as is also the case with boarding combat.
A successful surprise attack will reduce the strength of the defenders in the first round of combat. The effect depends on your leadership abilities, but can vary from -10% to -30%.
An attacking force that tries to flank attack will detach 30% of its force to the flank. The remainder of the force will face off against the garrison during this period.
Depending on the situation in the battle, a battle event may occur after the first round. This will usually be some situation that has occurred during the battle, to which you may have the opportunity to react; depending on your reaction, your or the enemy forces may gain a bonus for the rest of the battle. Often, you will have the opportunity to retreat your forces at this point.
Once the battle event has been resolved, the second round of the battle is fought. If the outflanking attempt succeeds, the flanking force will now join the force with triple strength (if the outflank fails, they will rejoin at normal strength).
At this point, the side that has scored the most total "hits" wins the battle. If you chose to plunder the town, you now receive your well-earned loot. If you chose to target destruction, the game now resolves the effects of the destruction. The greater the victory, the more devastating is the effect of the destruction. You also gain a little plunder.
To capture a region, it is not sufficient to win the battle. Under normal circumstances, you will have to score twice as many hits as the defending force to conquer the region. If the defenses of the region have previously been damaged, this requirement is reduced dependent on the previously inflicted destruction in the region. A captured region is turned over to a governor of the empire you are fighting for. Plunder gained during conquest is minimal.