At the time, another boat, the AWOL, was also in the area with seven people on board, with some of the passengers diving.
AWOL’s skipper erected a diving flag to warn other vessels there were people in the water, Maritime NZ’s manager general regulatory operations, Jason Lunjevich, said.
“If a diving flag is erected, other vessels within 200 metres of the flag need to slow down to five knots.
“This is to protect divers.”
Rain or Shine did slow down from 18 knots but it was still travelling through the 200m five knot area at speeds of between 10 to 13 knots, more than double the permitted speed.
Witness reports described how passengers on AWOL tried to make the skipper of Rain or Shine aware there were people in the water, but said there was no change in speed.
Shortly after they heard a bang and a diver surfaced yelling for help.
The diver suffered cuts to his head and concussion as a result of the impact.
“This was completely avoidable and needlessly put a diver at serious risk of injury,” Lunjevich said.
“We are still in our busy period for recreational craft users, and diving, and we do not want to see repeats of incidents like this.”