In this undated photo provided by Maritime New Zealand, the yacht Nina is tied at dock at a unidentified location. Searchers said Thursday, June 27, 2013, they have grave concerns for seven people aboard... (Associated Press) 
 
 A New Zealand meteorologist took the last known calls from the seven people aboard an American schooner, "The weather's turned nasty, how do we get away from it?" 
 
 The phone calls and texts ended June 4. More than three weeks later, searchers said Thursday they have grave concerns for the crew on the classic 85-year-old wooden vessel that went missing while sailing from New Zealand to Australia. Attempts to contact the crew by radio and an aerial search this week have proved fruitless. 
 
 Authorities say the skipper of the 70-foot (21-meter) vessel Nina is American David Dyche. They say there are two other American men and three American women aboard, aged between 17 and 73. Also aboard is a British man, aged 35. 
 
 Messages posted online by friends indicate the boat originally left from Panama City, Florida. 
 
 Meteorologist Bob McDavitt said he took a satellite phone call from the boat June 3. A woman named Evi asked how to get away from the weather. He said to call back in 30 minutes after he'd studied a forecast. She did. 
 
 "She was quite controlled in her voice, it sounded like everything was under control," McDavitt said, adding that the call itself indicated she was concerned about the conditions. 
 
 McDavitt said he spoke only briefly to Evi, advising her to head south and to brace for a storm with strong winds and high seas. The next day he got a text, the last known communication from the boat: "ANY UPDATE 4 NINA? ... EVI" 
 
 McDavitt said he advised the crew to stay put and ride out the storm another day. He continued sending messages the next few days but didn't hear back. Friends of the crew got in touch with McDavitt soon after that, and then alerted authorities June 14. 
 
 Kevin Banaghan, who is spearheading search efforts by Maritime New Zealand's Rescue Coordination Centre, said rescuers weren't worried at first because there had been no distress call from the boat and its emergency locator beacon had not been activated. He said rescuers on June 14 initiated a communications search, in which they tried contacting the boat over various radio frequencies as well as contacting other vessels in the area to see if they'd spotted the Nina. 
 
 This week, he said, rescuers escalated their efforts. An Air Force plane on Tuesday searched the area where the boat went missing. A second search by the plane on Wednesday went as far as the Australian coast but again turned up nothing. Banaghan said searchers are considering their next options. 
 
 The boat left the Bay of Islands in northern New Zealand on May 29 bound for the port of Newcastle, near Sydney. The last communication was from 370 nautical miles west of New Zealand. 
 
 Banaghan said the crew hoped to arrive in Australia mid-June but that, given the conditions, he considered a realistic arrival date to be about June 25. He said Dyche is a qualified captain and the crew has varying degrees of experience. 
 
 "We're very concerned for their safety and wellbeing," he said. 
 
 Authorities say the storm three weeks ago saw winds gusting up to 110 kilometers (68 miles) per hour and waves of up to 8 meters (26 feet). 
 
 Banaghan said the Nina is a "lovely old craft" which won races when it was new and had been maintained in excellent condition. He added that it had a new engine installed in recent months which had apparently created some initial leaking problems. 
 
 He said there are several possible scenarios, including the boat losing communications, drifting off course, or the crew taking to lifeboats. He said there's also a possibility the boat suffered a catastrophic failure and sank before anybody had time to react. ||||| Story highlights The Nina has given off no signs of life since early June 
 
 The racing schooner built in 1928 had seven passengers on board 
 
 Six Americans and one Briton are missing 
 
 The ship is equipped with modern tracking and communications devices 
 
 A historic racing sailboat and its crew of seven, including six Americans, have apparently vanished on the high seas. 
 
 A wooden schooner built in 1928, the Nina, left port in northern New Zealand at the end of May and dropped out of communication a week later, a maritime safety authority said Thursday. 
 
 It was en route to Newcastle, Australia. 
 
 The sailing yacht is equipped with a tracking device, a satellite phone and an emergency buoy, but none of them have been heard from since early June, according to Maritime New Zealand. 
 
 At the time of its last sign of life, the Nina was nearly 400 miles northwest of New Zealand in the Tasman Sea. 
 
 Family members alerted maritime authorities in New Zealand in mid-June that the sailboat may be missing. Rescuers issued alerts to vessels in the area. None reported having seen the Nina. 
 
 Two extensive sweeps by a reconnaissance plane came up empty. 
 
 The Nina was carrying one British passenger along with the six Americans. 
 
 Shipwreck survivor recounts drama on high seas 
 
 Wisdom from the sea: 'React fast or be swept away'
– Six Americans and a Brit have vanished without a trace on the high seas between New Zealand and Australia, aboard the 70-foot vessel the Nina, CNN reports.The crew was last heard from on June 4 while battling rough conditions—68mph gusts and waves as high as 26 feet—about a week after their historic schooner left New Zealand's Bay of Islands. Friends reported the vessel missing on June 14, and the fact that its emergency beacon was never activated gave rescuers hope. But the picture that's forming of the Nina's last known movements sounds less promising. A woman aboard the 85-year-old vessel called a New Zealand meteorologist via satellite phone on June 3, asking him, "The weather's turned nasty, how do we get away from it?" They spoke briefly, with Bob McDavitt advising the group to sail south. The following day he received the following text: "ANY UPDATE 4 NINA? ... EVI." After that, the boat vanished, with two aerial searches turning up nothing. More foreboding details, per the AP: The rescue coordinator says the boat realistically should have arrived in Australia two days ago, and the Nina dealt with some leaking issues earlier this year after a new engine was installed. He expressed "grave concerns" to the Age.