The Forts

The Forts part 1
The Forts part 2

Before beginning this mission it is recommended that you upgrade the Mortar of the Jackdaw.  Gather enough metal to purchase a set of copper Mortars (level 2). Once that is done sail over to the Fort to start the mission. There will be 1-2 brigs near the fort so be ready to fight them off. To damage the fort aim the Mortar shot at any of the two highlighted corners of the fort and fire a Mortar at it to do some serious damage and complete the objective You do not need to destroy the fort with Mortars but i recommend because you can be further out and destroy the defenses but watch out for the base's mortars because they will hurt your ship. After the defenses are blown up a quick cutscene occurs and then you can dock the Jackdaw at the fort entrance. Bring the boat in then run up the steps and scale the fiery rubble to the inner fortress. Move forward into the burning fortress to find the officer. Use a Running Assassination on him to complete the objective. Once the officer is down, the guards at the fortress surrender. From there make your way to the War Room at the top of the fort to complete the mission