LOVELL, Maine — A family vacation turned into a nightmare Tuesday, when a 15-year-old girl had her leg severed on Kezar Lake after her father crashed the family boat into a submerged rock “barely visible from the surface,” according to the Maine Warden Service.

Abby Mueller, of Houston, Texas, was ejected from the boat when the 24-foot Correct Craft motorboat struck the rock. The propeller severed her leg from her knee downward after the boat “ran over” her, police said.

Mueller was flown to Massachusetts General Hospital in Boston. Her status wasn’t immediately known. A hospital spokeswoman said the hospital doesn’t comment on patients involved in crashes.

According to the warden service, the crash area was marked with five hazard buoys. The boat struck a rock inside the marked hazard area.

Alcohol wasn’t believed to be a factor in the incident, which happened at 2:45 p.m.

Six people — all family members — were present during the crash.

A 13-year-old boy was tubing off the back of the boat. Three teenage girls were sitting in the bow (one age 13 and two 15-year-olds). And a 10-year-old boy was sitting on the back of the vehicle.

Three of the children belonged to the father and boat driver, 44-year-old Robert Mueller.

The two others were family cousins from Woodstock, Conn.

Robert suffered a cut to the head during the crash. All three teenage girls were ejected from the boat upon impact, but it appears only Abby suffered serious injury.