WINTHROP — Four teenage boys and their camp counselor are injured but safe after the motor boat they were riding in Monday morning capsized in the northern end of Lake Cobbossee.

The four campers and the counselor were from Camp All-Star, an overnight sports camp at Kents Hill School in Readfield.

One of the four teens was on the lap of counselor Mark Cloutier, 20, learning to operate the 2004 Mastercraft ski boat, said Deborah Turcotte, spokeswoman for the Maine Warden Service.

“The teen pulled the power lever down too fast and it sent the boat into a nosedive,” Turcotte said.

The windshield shattered and one of the three passengers sitting in the back was ejected, she said.

Then, the boat capsized. Turcotte said the watercraft was traveling about 40 mph.

The Maine Warden Service and Winthrop Fire and Police departments responded, pulling the five to safety and turning the boat upright.

“From my understanding, they were out of the water pretty quickly,” Turcotte said.

One of the five was wearing a life preserver, Turcotte said, though the boat had other life jackets on board. The boat was current on all safety standards, she said.

The campers — two 14-year-olds, a 15-year-old and an 18 year-old — suffered lacerations on their arms and legs that appeared to require stitches, Turcotte said. Cloutier, Camp All-Star’s wakeboarding director, suffered some bruises from the incident.

The capsizing happened around 10 a.m. between Upper Sister and Lower Sister islands in Lake Cobbossee.