Rather than risk putting divers down to retrieve the boat while it was moving, Mr Harman said they were "letting nature take its course" and would wait for high tide before trying to retrieve the vessel.
Swimmers had been warned to stay out of the area near the Waimarama boat ramp. Boats out on the water were also advised to stay aware of the situation.
Yesterday a police spokeswoman said the boat had "rolled in" with the surf by 4pm.
It was recovered but reportedly "written off".
It had already been a busy day at the popular Hastings beach - Mr Harman said even though conditions weren't the best for swimming, during the afternoon there were about 300 swimmers in the water, with another 600 people enjoying the sun on the beach.
A similar incident occurred at Waimarama in 2012. A boat sank about 50m from the beach shortly after being launched when it was swamped by a wave. The three occupants were unharmed.