Six Americans have been missing at sea for more than three weeks after setting sail from New Zealand, officials said Thursday.
Three males -- aged 17, 28 and 58 -- and three women -- aged 18, 60 and 73 -- along a 35-year-old British man were aiming to sail the 70-foot schooner Nina to Newcastle, Australia.
A statement from Maritime New Zealand released early Thursday expressed "grave concerns" for the Nina's crew.
The vessel left the Bay of Islands area of northern New Zealand on May 29. It has not been heard from since June 4, when the ship was 370 miles west-north west of Cape Reinga in "very rough" conditions with winds gusting to 68 mph and 26-foot swells.
Authorities said the vessel's emergency beacon has not been activated.
Rescue Coordination Centre New Zealand search and rescue mission coordinator Kevin Banaghan said that a military aircraft had covered a 160,000 square nautical mile search area on Tuesday, with an additional 324,000 square nautical miles examined on Wednesday.
"No sign of the vessel has been found," Banaghan said. "We do hold grave concerns for the Nina and her crew but remain hopeful of a positive outcome."
The huge search was launched after family and friends raised concerns about the crew's whereabouts.
The Nina was built in 1928. It is also equipped with a satellite phone and a spot beacon, which allows tracking signals to be sent manually.
6 Americans vanish at sea while sailing from New Zealand to Australia - World News