Naval Combat

Starting Combat: When combat begins, allow the PCs (and important NPC allies) to roll initiative as normal— the ship itself moves and attacks on the captain’s initiative result.
Movement: On the captain’s initiative count, the ship can move its current speed in a single round as a move-equivalent action for the captain (or double its speed as a full-round action), as long as it has its minimum crew complement. Alternatively, the captain can change direction (up to 90 degrees) as a move action. A ship can only change direction at the start of a turn.
Attacks: Crewmembers in excess of the ship’s minimum crew requirement can be allocated to man siege engines. Siege engines attack on the captain’s initiative count.
A ship can also attempt to ram a target if it has its minimum crew. To ram a target, the ship must move at least 30 feet and end with its bow in a square adjacent to the target. The ship’s captain then makes a Profession (sailor) check— if this check equals or exceeds the target’s AC, the ship hits its target, inflicting damage as indicated on the ship statistics table to the target, as well as minimum damage to the ramming ship.
Sinking: A ship gains the sinking condition if its hit points are reduced to 0 or fewer. A sinking ship cannot move or attack, and it sinks completely 10 rounds after it gains the sinking condition. Each hit on a sinking ship that inflicts damage reduces the remaining time for it to sink by 1 round per 25 points of damage inflicted. Generally, non-magical repairs take too long to save a ship from sinking once it begins to go down.

Ship Statistics Ship type: The general type of ship
AC: A ship’s base AC. Add the captain’s profession (sailing) bonus to this base. Add +1 for every 10ft of movement speed. Ships have a front, back, and flank AC.
HP: The ship’s hit points.
Saves: Fortitude, reflex, and fortitude saves. Add the captain’s profession (sailing) bonus
Speed: The first number indicates how many feet it can move in one round of combat. The second indicates its speed in knots.
Arms: The number of siege engines the ship can hold. Different siege engines have different values. For example, a set of 4 basic canons counts as 1 siege engine, not 4.
Ram: The amount of damage the ship inflicts on a successful ramming attack (without a ram siege engine).
Squares: The number of squares the ship takes up on the battle mat. A ship’s width is always considered to be one square.
Crew: The first number indicates the minimum requirement to sail the ship, the second indicates the maximum number of people it can accommodate.
Weight: The average weight (cargo and passengers) the ship can hold.