The incident happened just after 4 p.m. when New Hampshire State Police received a call about boat on fire in the Piscataqua River, near Little Harbor in Newcastle.
The 70-foot vessel named 'Elusive,' was heading towards Wentworth Marina when a passenger noticed black smoke below the deck.
Within minutes, the boat completely filled with smoke, according to passengers.
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Police say three passengers, two from Connecticut and one from Florida, as well as two family dogs, jumped overboard as the boat became engulfed in flames.
They were rescued by nearby boats and taken to shore. They were then taken to Portsmouth Hospital, where they were treated and released.
The vessel drifted out of the harbor and efforts to save the boat were unsuccessful, according to state police.
Within two hours of the initial call, the boat sank in waters off of Maine.
The cause of the fire is unknown.
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