A Canadian navy warship that was badly damaged in U.S. waters by a massive fire at sea in February is on its way back to Canadian waters, under tow by a U.S. tug, CBC News has learned.

HMCS Protecteur departed Pearl Harbor on Thursday morning under tow from USNS Salvor, beginning a slow voyage across the North Pacific back to its home port of CFB Esquimalt near Victoria, B.C. 

There are four Royal Canadian Navy sailors aboard Salvor for the sail home.

"She's making six knots right now, which is good," said navy spokesman Lt.-Cmdr Des James. "From our perspective, everything looks promising."

HMCS Protecteur

Sailors aboard the guided-missile cruiser USS Chosin observe HMCS Protecteur during a towing operation in February. (United States Navy and Mass Communication Specialist 3rd Class Johans Chavarro/Facebook)

The trip under tow is expected to take as long as three weeks, depending on the weather, but it could be Protecteur's last trip.

Commissioned in 1969, the ship was due to be retired in 2017, but the damage aboard following two fires at sea over three days was so severe that it's likely repairs will be too expensive for the navy to consider for just a couple years of service.

"It's still too early to make those calls," said James.

"We have to wait 'til we get her alongside and then get on board and get a detailed damage assessment. That work will happen in the next weeks or months. There's still a long journey ahead."

About 20 crew suffered minor injuries — including dehydration, exhaustion and smoke inhalation — fighting the first of the two fires, an effort that lasted more than 11 hours.

The vessel was more than a day — and 600 kilometres — out of Pearl Harbor in the north Pacific in rough seas at the time the fire broke out.

Sailors were able to save the ship from sinking, but it nevertheless lost all power, including the ability to generate electricity to run communications gear and pumps to fight the blaze.

It took a week for the U.S. navy to tow the ship into Pearl Harbor after the incident.

With files from James Cudmore