An American schooner missing in the South Pacific with seven people aboard sent an undelivered text message a month ago saying its sails were shredded and it was traveling at four knots.

New Zealand's Rescue Coordination Centre released the last-known message from the 70-foot (21-meter) Nina Thursday after seeking it from satellite phone company Iridium and the U.S. State Department.

The June 4 message with a misspelling read: "Thanks storm sails shredded last night, now bare poles. Goining 4kt 310deg will update course info (at) 6PM".

Authorities believe the Nina likely sank in a storm that day but have continued an aerial search, hoping that survivors may have made it into a life raft the boat was carrying or to land. The 85-year-old classic wooden sailboat had left New Zealand six days earlier bound for Australia.

Nigel Clifford, Maritime New Zealand's general manager of safety and response services, said the message indicated the Nina would update its position about six hours later, which it never did.

"While it shows that Nina had survived the storm up to that point, very poor weather continued in the area for many hours and has been followed by other storms," Clifford said in a statement.

Authorities didn't state why the text message went undelivered or who it was sent to. Maritime New Zealand said it would review its search options again overnight.