Part 1: Naval Combat
Fort Baie Rouge is probably the most difficult fort in the game to take down, not only due to its five defence towers or mortars emanating from the fort itself, but due to environmental factors. The fort is in a much more cordoned of location and as such it is quite difficult to manoeuvre around quickly and effectively. This is made even worse by the presence of numerous icebergs and of course enemy ships that frequently sail around this area.
As you approach, make it a priority to clear out some of the icebergs. You’ll also want to mortar bomb any ships in the area and draw them out away from the fort so that you can take them down out of range of the fort’s constant mortar fire. Once the ships are clear the naval attack of this fort is a fairly simple matter of unleashing broadsides and mortars into the walls over a couple of passes back and forth in front of the fort. After the defences are done, move in and dock in the area permitted.
Part 2: Infiltrate
As you get off the ship, take the fallen tree stump to the right to find an alternate, stealthier entry into the fort. Air assassinate the pair of guards at the end. Directly below you will be the first of three powder kegs that we need to destroy – ignore that for now and instead look for the sniper in the tower ahead just to our right, use the rope to cross to this and take him out. From the two sniper towers in the area you should be able to see all three of the powder kegs we need to destroy, so shoot them all (one is out of range of your pistols, so use the guard’s rifle to shoot it) when you see the opportunity.
Now, use the ropes and rooftops nearby to race over to the other sniper tower, take him out and then make your way to the main fort. Kill the captain here to complete the takeover.