The caller said 2 of the four people were hurt; one of them had a serious head injury.
Medics and marine units arrived to find the boat had hit a buoy and was sinking, according to police. The injured were taken to Frankford-Torresdale Hospital.
The damaged boat, a cutter about 24 feet long, was towed to the New Jersey State Police Marina in Burlington, New Jersey.
The investigation into the accident is underway.
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