Final answer:
Boat registration in Alaska is valid for 3 years for non-commercial boats and 1 year for commercial fishing and charter boats.
Step-by-step explanation:
The length of time boat registration is valid in Alaska depends on the type of boat. For non-commercial boats, the boat registration is valid for 3 years. However, commercial fishing boats and charter boats have a registration period of 1 year. It is important to renew boat registration before it expires to avoid any fines or penalties.