The crew of the USCGC Polar Star freed an Australian fishing vessel from thick pack ice Friday night approximately 900 miles northwest of McMurdo Sound, Antarctica.

The 207-foot FV Antarctic Chieftain contacted Rescue Coordination Centre New Zealand earlier this week after becoming beset in ice with 27 people aboard, reporting that three of its four propellers have been damaged by ice and it had lost its ability to maneuver. The RCC New Zealand then diverted the Polar Star, more than 330 miles away, to respond to the vessel.

After rendezvousing with the fishing vessel overnight Thursday, the crew of the Polar Star was able to take the Antarctic Chieftain in tow. The USCG reported that the vessels are surrounded by 12 to 15 feet thick ice covered with two feet of snow.

The Coast Guard said that upon reaching a small area of open water, the Antarctic Chieftain will commence testing the vessel’s ability to steam under its own power. Once this testing is complete, Polar Star and the Antarctic Chieftain will proceed north through another 60 miles of ice.

The 399-foot Polar Star is nearly 40-years old and the nation’s only heavy icebreaker capable of operating in the thick Antarctic ice.

Before being diverted, the 150-person crew of Polar Star was deployed to McMurdo Station, Antarctica as part of Operation Deep Freeze.