Optional Missions:
- Kill 4 guards
- Use heavy shot to incapacitate the Man O' War
Before attempting this mission, make sure you have an ample supply of Heavy Shots.
To head to the next mission, sail north of Abaco Island and head to the mission marker. After the cutscene, follow the stranger and until you enter a restricted area full of royal navy guards. Turn on Eagle Vision to tag him. Start listening to the conversation while being hidden when you are prompted to do so. Utilize Eagle Vision again to tag more enemies. Kill four guards from stalking zones along the way to complete your optional objective. Keep eavesdropping until the cutscene is triggered.
After the bombardment, sprint to the Jackdaw before the timer runs out, then immediately sail out. You'll have to engage the Man O' War. This should be a pretty easy encounter especially if the Jackdaw is equipped with the best parts you can purchase at this point. For the secondary optional mission, attack the Man O' War until its armor gets critically low - enough for it to be taken down by a single Heavy Shot fire. Get close to it and once you're beside it, fire a heavy shot round to incapacitate it.
Board the man o' war and shoot the gunpowders, kill the officer and eliminate the required number of enemy crew members. Keep fighting until a cutscene is triggered. After that, board the Jackdaw and escape the zone. Don't bother fighting off the remaining ships since the Jackdaw will be critically damaged at this point and there are invulnerable ships in the opposing navy preventing you from getting your revenge.
Thanks