Eu-regulation 1177/2010 concerning passenger rights
EU-regulation 1177/2010 applies pursuant to section §418a of the Norwegian Maritime Code for passenger transport in Norway. The regulation gives you as a passenger the following rights (summary):
Assistance for persons with reduced mobility
Persons with reduced mobility shall not be discriminated against. This passenger group is entitled to free assistance appropriate to their individual needs during boarding and disembarkation, and while on board the vessel.
Delayed or cancelled departure, information
Passengers on board are entitled to information regarding operational disruptions within 30 minutes after planned departure, as well as updated information when available.
Delayed or cancelled departure from port terminal and pre-purchased tickets
In case of cancellation or delay of more than 90 minutes after schedule, according to the regulation passengers have a right to assistance, a change of journey, refunded ticket price, or the right to partial compensation of the ticket price with more than 60 minutes delayed arrival. 
Complaints or compensation claims must be sent within two months, read more here
Passengers who wish to do so, may complain to the Travel Complaint Handling Body (Transportklagenemnda) after first complaining to the carrier.
Travel Complaint Handling Body
Øvre slottsgate 18 – 20
Telefon: +47 22 54 60 00
Norwegian Maritime Authority is the national regulatory body for the regulation:
Norwegian Maritime Authority
Telefon: +47 52 74 50 00
 The regulation applies to travel over 500 meters with ships of more than three crew personnel, and which is certified for more than 12 passengers.
 Applies only when the carrier is notified of the trip and the concrete requirements for assistance at least 48 hours before departure. Even if the notification is not received within the deadline, the carrier shall provide assistance as far as possible so that the passenger may travel with the vessel.
 These rights apply only after the passenger has purchased a ticket and only if a ticket is purchased with the departure time displayed on the ticket. Rights in case of delayed arrival do not apply when delays are due to weather conditions or other extraordinary circumstances.
 The right to assistance in case of delays only applies to travel from port terminals.