The longliner Antarctic Chieftain, carrying 27 crew, was caught amid thick ice and suffered propellor damage as it fished near the Ross Sea, far south-east of New Zealand.

Owned by the Tasmanian-based company Australian Longline, Antarctic Chieftain is in clear water amid large ice floes and has suffered no hull damage, according to Rescue Coordination Centre New Zealand.

    “A combination of an unexpected build-up of ice floes 2-3m. thick and damage to the propeller means it cannot get back to the open sea without assistance,” RCCNZ manager  Mike Hill said.

    The US icebreaker Polar Star was headed north out of Antarctica after its annual voyage to clear a channel into the Ross Sea and McMurdo Base when it was diverted to the scene.

    Polar Star will steam more than 300 nautical miles and expects to break three-metre ice, to reach the Antarctic Chieftain, according to a Coast Guard statement.

    “The considerable geographic distances and extreme environmental conditions make this a complex rescue mission,” said Capt. Matthew Walker, commanding officer of the Polar Star.

    RCCNZ said the icebreaker was likely to reach the area late on Friday or early on Saturday, depending on progress and weather conditions.

    The crew of 27 was not at risk and there has been no spill of oil, or environmental event, it said.

    Mr Hill said once the icebreaker arrived at the scene, it may take some time to break through the ice to reach the Antarctic Chieftain.

     “But the fishing boat is well-equipped with supplies and weather conditions are reasonable for the area,” Mr Hill said.

    The Antarctic Chieftain’s sister-ship, Janas, is also proceeding to the area and is expected  to escort or tow the vessel to the nearest safe harbor once freed.

    US Coast Guard Vice Admiral Charles Ray, commander of the Pacific Area, said the incident was a “sobering reminder” of the importance of U.S. icebreakers as human activity increased in the polar regions.

    The nearly 40 years old Polar Star is the only American heavy icebreaker capable of operating in the thick Antarctic ice for a mission such as breaking out Antarctic Chieftain, or clearing McMurdo Sound for the critical annual resupply of McMurdo Station.

    Last summer Polar Star was tasked to break out the trapped tourist ship Akademik Shokalskiy, but ice conditions changed and the Russian vessel freed itself.

    Comment was sought from Australian Longline in Launceston.