"This incident could easily have resulted in multiple fatalities, but for the fact that the life jackets on the boat floated to the surface near the boat following the capsize, and the occupants were then able to grab them."
The group of four were able to make their way to Matakana Island, where they were rescued by a passing boat.
Once the alarm was raised a search immediately began for Mr Mair but he was not found. His body was discovered floating in the sea off Whiritoa beach on February 7.
Coroner Ryan said he was satisfied from the evidence provided that an extensive search was undertaken for Mr Mair.
It was a legal requirement for every pleasure boat to have a personal flotation device (PFD) on board for each person while in Tauranga Harbour.
The Bay of Plenty Regional Council's guide for safe use of the harbour stated it was a legal requirement for everyone to wear a PFD in all situations where there was a heightened risk and Mr Ryan believed that would have applied on the night of the accident.
Mr Mair should have been aware of the requirement as he was the skipper of a boat using the harbour, Mr Ryan said.
"This responsibility was even greater, given that he was carrying passengers.
"Mr Mair has paid the greatest penalty for failing to observe best practice, if not legal requirements, for the safe operation of a pleasure boat."