This is Adelaide Drubman’s base of operations occupied by the peggies. On top of the foot soldiers in and around the marina, you also have to take out the cultist gunboat patrolling the docks. You can use the nearby mountainside as a sniping position but you can’t stay there for long, especially after the peggies react to your attacks since they also have a mortar stationed there.
After picking off the enemies using sniper fire, let the heat cool down first so you can slowly get near the location. Save the patrol boat for last. If you’re able, it’s easier to blow it up using a rocket launcher or explosive if you’re able to get near. Keep Boomer with you as you sneak in since there might be peggies you weren’t able to tag earlier.