The Changing Tide DLC, Far Harbor Quest
This quest will be triggered or can be aquired when you complete Rite of Passage quest.
Related points of interest
Stages of "The Changing Tide" quest
1. Help Mitch
After completing the Captain's Dance, I've earned the town's respect. Far Harbor still faces many challenges and could use my help.
Talk to Mitch, he is inside The Last Plank tavern. He will ask you to help him find his uncle. To do this, you will have to complete one more side quest The Hold Out.
2. Help Small Bertha
Talk to Small Bertha. She will ask you to help her to clear the land. To do this, you will have to complete one more side quest Turn Back the Fog.
3. (Optional) Help the Mariner
Talk to the Mariner. She will ask you to help her to kill trappers. To do this, you will have to complete another side quest Hull Breach 2.
4. (Optional) Help Cassie Dalton
Next / new quests are Hull Breach 2 (DLC, Far Harbor), The Hold Out (DLC, Far Harbor), Turn Back the Fog (DLC, Far Harbor).