Fears For Seven On Board Rescue officials say they have "grave concerns" for seven people aboard a US schooner that has been missing for three weeks between New Zealand and Australia. Authorities said the Nina, an 84-year-old wooden vessel, is skippered by American David Dyche. There are two other American men and three American women aboard, aged between 17 and 73, and a 35-year-old British man. Maritime New Zealand said extensive searches by plane this week had found no sign of the 21m (70ft) schooner. It set off from the Bay of Islands settlement of Opua on New Zealand's North Island on May 29 bound for the Australian city of Newcastle, north of Sydney. A New Zealand meteorologist took the last known calls from the crew on board the yacht when it was about 370 nautical miles west of New Zealand. The weather's turned nasty, how do we get away from it? Bob McDavitt was asked when he took a satellite phone call from Nina on June 3. A storm around at the time saw winds gusting up to 110km/h (68mph) and waves of up to 8m (26ft). A woman named Evi asked Mr McDavitt how to get away from the weather. "She was quite controlled in her voice, it sounded like everything was under control," Mr McDavitt said, adding that the call itself indicated she was worried about the conditions. The boat left the Bay of Islands and was bound for the port of Newcastle Mr 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, which said: "ANY UPDATE 4 NINA? ... Mr 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 did not hear back. Friends of the crew got in touch with Mr McDavitt soon after that, and then alerted the authorities on June 14. Rescue coordinator Kevin Banaghan said the yacht had an emergency beacon, which had not been activated. "Unfortunately, no sign of the vessel has been found," Mr Banaghan said, adding that conditions were "very rough" when it went missing. We do hold grave concerns for the Nina and her crew, but remain hopeful of a positive outcome. Mr Banaghan said Mr Dyche is a qualified captain and the crew has varying degrees of experience. Authorities expected it to have arrived in Australia by this week. Mr Dyche, his wife Rosemary and son David, 17, left Florida on board the Nina in 2008 to circumnavigate the world, according to New Zealand newspaper The Northern Advocate. They travelled through the Bahamas, Jamaica, Columbia, Panama, Costa Rica and French Polynesia before arriving in New Zealand. A Facebook profile in the name of David Dyche III has pictures of the Nina and a post from May 21 apparently referring to the upcoming voyage to Australia with his son. Dave is leaving and going to college in the States in July. This is our last trip together crossing the Tasman Sea," it reads. On May 26, he said he expected rough weather, posting: "The Tasman Sea is shooting gales out like a machine gun, living up to its reputation. We are shooting at leaving out after the first one this week. No doubt we will be dancing with one or two of them.