NEW CASTLE, N.H. – The Coast Guard is searching off the New Hampshire coast for a 46-year-old lobsterman from Maine.

Coast Guard officials said two people were rescued, but a third, Christopher Tobey, 46, of Kittery, was still missing. The boat was the 44-foot Save-A-Buck out of Kittery, Maine.

The two rescued fishermen were found on Duck Island, an island in the Isles of Shoals. One of the rescued was Tobey’s 16-year-old son, and the other was a 21-year-old crewman. Their names were not released.

Coast Guard Petty Officer Luke Pinneo said the search began when Tobey’s daughter reported the boat missing at about 10 a.m. Monday. She said it was due back at 5 p.m. Sunday. Search crews were dispatched, and a helicopter was launched from Cape Cod.

Officials said the boat capsized Sunday night, and the three started swimming together. The teen was helping his father swim, but at some point, Tobey went under. The two survivors swam to Duck Island and built a fire.

The fishing vessel Amanda T spotted what was left of the Save-A-Buck crashing on rocks Monday morning. A private skiff rescued the two survivors from Duck Island.

Pinneo said the water is cold this time of year, raising concerns of hypothermia. But doctors said the two men did not have hypothermia and were treated Monday afternoon and released.

The Coast Guard planned to continue searching the 48-degree water into the night.