Sonar searches of the seabed are underway during today's search for the Rotorua fisherman who has been lost at sea for at least 39 hours.
The 24-year-old fisherman was reported missing at 11.20pm on Monday after another fisherman located his two companions who had washed ashore.
The missing man's brother-in-law and 10-year-old nephew were treated and discharged from Tauranga Hospital on Tuesday.
Their vessel, a 4m aluminium dinghy, overturned as they crossed the Bowentown Bar.
Chief Petty Officer Daniel Bramley, from the Auckland-based HMNZS Matataua unit, said Navy personnel spent about three hours today sonar mapping the seabed looking for any objects of interest.