The objective of this mission is to destroy the armed forts defences, before entering the fort and taking out the leaders. To begin with we need to crack open the fort itself.
The fort’s defences consist of two cannon towers overlooking the water, each marked with a red objective marker. Hitting them with attacks will display a health bar so that you can track how much damage you have caused. In addition to the towers, the fort will launch mortars into the ocean in a bid to hit you.
Remember that mortars and enemy attacks will appear as colours on the water with yellow and red indicating where their weapons are targeting. If you see your ship in the range of the red water, tell your men to brace immediately to avoid taking too much damage or immediately manoeuvre out of the area.
To take down the fort, use a mortar if you have one to damage the defences for the optional objective. Afterwards, I’d recommend sailing back and forth in front of the fort, using your broadside attacks and heavy shots to deal damage over a larger area. Then use the swivel gun to pop the weak spots when they become visible.
Once all of the defences have been destroyed, a green waypoint marker will appear next to the fort allowing you to dock.
Climb the stairs until you reach the blocked gate. Climb the broken wall to the right of the gate and drop down the other side. Clear out the immediate area of enemies and climb the makeshift ramp on the right of the area. Continue through the archway here into another small courtyard. Quickly sprint over and kill the officer here with a running assassination for the second optional objective.
Once the officer is down, scale the building at the back of the courtyard until you reach the roof. Run over and enter the door marked with the green objective marker. This will liberate the fort and complete the mission.