Three boaters were rescued Sunday night after their 20-foot vessel struck a sand bar near Robins Island, leaving them stranded, authorities said.

The Southold Town Police and Cutchogue and Mattituck fire departments responded to a call of boaters in distress on Robins Island, a 435-acre private island in the Great Peconic Bay.

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The 20-foot center console boat ran aground on the sandbar at about 8:30 p.m. and the passengers were stranded on the island, Southold Town Police said.

Two of those on the boat were taken to Eastern Long Island Hospital in Greenport for treatment of hypothermia while the third declined medical attention, authorities said.