An independent review of the search for the missing schooner Nina has found the Rescue Coordination Centre New Zealand went beyond what many overseas authorities would have done.
Nina and its seven crew members left the Bay of Islands on May 29, 2013 bound for Newcastle but was last heard from on June 4, 2013 when the vessel was about 370 nautical miles northwest of Cape Reinga.
Records showed that conditions at the Nina's last known position were very rough.
The Rescue Coordination Centre New Zealand (RCCNZ) co-ordinated nine searches for the schooner and its life-raft in June and July 2013.
The search covered 737,000 square nautical miles, including around Lord Howe and Norfolk Island. Shoreline searches were also carried out on the west coast of New Zealand.
On board were Americans skipper David Dyche III, 58, his wife Rosemary, 60, their son David Dyche IV, 17, Evi Nemeth, 73, Kyle Jackson, 27, Danielle Wright, 18, and Briton Matthew Wootton, 35.
Family members of the crew on board Nina have been critical of search efforts and were frustrated when they were called off.
David Baird, former general manager of the Australian Maritime Safety Authority's emergency response division, conducted the independent review at the request of Maritime New Zealand director Keith Manch.
Mr Baird found that in many areas, RCCNZ demonstrated "conviction, compassion and determination to achieve a satisfactory result" in their search.
"In many areas RCCNZ went well beyond the requirements of the Search and Rescue Convention and its standard operating procedures.
"RCCNZ went further in effort, resource allocation, consultation and duration than many of the other highly-regarded [search and rescue] authorities would have done."
Mr Manch said he felt it was appropriate to have an independent review of the search because of the complexity of the operation and the overseas agencies involved.
Maritime New Zealand's general manager of safety and response services Nigel Clifford said the review confirmed the results of internal debriefs of the search operation.
"The independent review confirms that everything that could have been done to find the Nina was done by RCCNZ - and that is something we believed was the case prior to suspending the search."
The review concluded with recommendations for RCCNZ.
Mr Baird recommended that RCCNZ improved handover procedures and processes for ranking different last known positions, developed better processes for notifying next of kin during searches, improve access to information from satellite phone providers, test the use of satellite imagery and develop measures to improve cruising boat safety.
Mr Baird said that the recommendations could have changed the timetable of action in the search for Nina but would not have changed the outcome of the search.
The families of the missing crew launched private searches for the schooner when RCCNZ concluded the search.