Almost 20 vessels have officially registered with authorities to sail through the Northwest Passage this year, but the true number may be much higher.

The coast guard says 19 vessels have formally registered with them for permission to cross through the passage this sailing season.

An ice-free Northwest Passage is seen in this handout satellite photo. Low ice levels are spurring dreams of commercial shipping in the region. (NASA)

Sailors have toyed with traversing the long-fabled shortcut between the Atlantic and Pacific oceans for centuries, but have traditionally been thwarted by frigid air, frozen waterways and hostile environments.

In recent years, however, melting sea ice has brough new interest in the idea of cutting shipping times by traveling between islands in the Arctic archipelago.

Large ships register with Canadian authorities, but several small pleasure and adventure crafts don't bother, because they don't have to. So the true number of vessels that will attempt the crossing could be much higher.

"Some of them we hear about them when they run into some problems, into some troubles, they get stuck in the ice for example," Jean-Pierre Lehnert of the coast guard in Iqaluit said Tuesday. "Then, we hear about them, so usually they're asking for some ice breaker assistance to get them out of the ice."

He says if all small craft were legally required to register, the coast guard would be better prepared to help them because they'd have access to ice and open water conditions.

Since the closure of the coast guard station in Inuvik, Lehnert and his team are now responsible for overseeing all of Canada's arctic waters, stretching from Iqaluit to the Mackenzie River delta

"It's a different thing where we had to adjust," Lehnert said. "We had some staff come from Inuvik, to give us training, and we have new equipment, brand new equipment, new systems put in place."