Trio suffer hypothermia after overloaded boat sinks in Waitematā Harbour with a 'full bin of fish'

Three people were treated for mild hypothermia after their boat sank. Photo / Bevan Conley

Three hypothermic boaties were plucked from the water after their overloaded boat sank beneath them in the Waitematā Harbour.

The trio were bobbing in the water east of Browns Island for "some time" before they were rescued by a passing yacht, a Coastguard spokesman said.

A Coastguard vessel, the Howick Rescue One, met the party around 12.25pm on Sunday afternoon after a rescue beacon was activated from the yacht.

The stricken boaties were treated for mild hypothermia but didn't need further medical treatment, the spokesman said.

"It was quite a small boat and they had a chilly bin full of fish, so we think it was overloaded."

Their runabout, measuring an estimated 3-4m, was later salvaged and towed to Crater Bay on Browns Island.

The day's catch was also successfully recovered.