The two regional boat routes in Nordland are both called "Nordlandsekspressen", which is abbreviated as "NEX".
NEX 1 is the route that goes between Bodø and Sandnessjøen.
NEX 2 is the route that goes between Bodø and Svolvær.
The departures and info about tickets for the ferry and express boats can be found here
Info about the different passenger quays is found here
The express boat terminal is in the town centre: