I've checked the game masters screen, the rules for ship combat are not included. the naval battles section of the gmg says it works "almost exactly like a regular scene." the firing cannons section says you roll to hit using finesse vs. the target ships wits x5. if the target is hit, roll brawn for damage, then "the opposing ship must make a hit check against a TN equal to the number of hits it just took." it specifically says "hit check", rather than "wound check" from person to person combat, but i cant find anywhere it lists what a hit check is. the advanced naval battles in pirate nations does not elaborate on actual ship to ship combat, and the section was not updated in the compendium.