Departing from Patagonia by boat:

People who goes to North from Patagonia may use flights or land transportation (cheaper but uncomfortable) or ferry boat.

There is one boat every week from Puerto Natales to Puerto Montt. You should book before your departure. Rates are higher on Summer Season, but the experience to sail through the channels worth the price and time. It is a three days sail. You may see many islands, one glacier, an old wreck, even disembark in Puerto Eden (a fishermen town). Travel agencies in all Patagonia sell tickets for this trip. (Lowest price USD 355 including food. Attention students, ISIC Carnet allows a 10% discount). There are also Internet offers. Try in Spanish search  on web Venta tickets Patagonia 

Patagoná´s channels