(Reuters) - The United States is sending a heavy icebreaker to help free an Australian fishing boat with 27 people on board that has been stranded since Tuesday in the icy Antarctic seas, the U.S. Coast Guard said on Wednesday.
The 207-foot (63-meter) Antarctic Chieftain has been stuck 900 miles (1,450 km) northeast of McMurdo Sound since Tuesday night.
Responding to a request for help from New Zealand authorities, the Coast Guard cutter Polar Star is scheduled to reach the vessel on Thursday evening, the Coast Guard said in a statement.
The vessel is unable to move after three of its four propellers were damaged by the ice, the statement said.
In order to get to it, Polar Star and its 150 crew members must travel some 330 miles, breaking through several miles of ice 9 feet (2.7 meters) thick and traveling through heavy snow and winds up to 35 miles per hour (56 km per hour), officials said.
"The considerable geographic distances and extreme environmental conditions make this a complex rescue mission," said Captain Matthew Walker, commanding officer of Polar Star. "However, we're confident in our ability to reach the Antarctic Chieftain and committed to ensuring the safety of life at sea no matter the challenges."
Once it breaks the vessel free from the ice, the New Zealand fishing vessel Janas is set to either escort or tow the Australian boat to the nearest safe harbor, the statement said.
The rescue is being coordinated between the Coast Guard and Maritime New Zealand.
The Coast Guard's Polar Star is 399 feet (120 meters) long with a maximum speed of 18 knots. The cutter is almost 40 years old and the only heavy icebreaker in the United States capable of operating in the icy Antarctic conditions, the statement said.
The Polar Star crew had just completed its annual mission, known as "Operation Deep Freeze," to break a channel through the sea ice of McMurdo Sound in Antarctica to resupply and refuel the U.S. Antarctic Program's McMurdo Station on Ross Island.
Last year, the breaker cut short its mission in January to help free a Russian ship and a Chinese icebreaker from the Antarctic ice.
"The seas of Antarctica are treacherous and unforgiving," said U.S. Coast Guard Vice Admiral Charles Ray. "This incident is a sobering reminder of the importance of the U.S. icebreaker fleet as we see increased human activity in the polar regions."
Reporting by Karen Brooks in Austin, Texas; Editing by Lisa Shumaker