Hull Breach DLC, Far Harbor Quest
This quest will be triggered or can be aquired during Living on the Edge quest.
Related points of interest
Stages of "Hull Breach" quest
1. Get power tools
In order to reinforce Far Harbor's wall ("the Hull") the Mariner needs special power tools. I've agreed to go to Eagle's Cove Tannery and collect them.
Power tools are in the basement.
2. Give the Mariner the tools
I've picked up the power tools the Mariner needs to repair and reinforce Far Harbor's walls ("the Hull"). Now I need to give them to her.
After leaving the building, you will meet Machete Mike. He will offer you 2000 caps / 2750 caps (charisma check) for the tools.
Mariner will pay you 450 caps.
3. Quest completed
If you sold the tools to Machete Mike then:
Instead of delivering the power tools to the Mariner, I gave them to Machete Mike for a much better pay day.
If you delivered the tools to the Mariner then:
I delivered the power tools to the Mariner.