An Eight-year-old Alexandria girl, her father and her grandfather drowned Sunday when their 15 1/2-foot boat capsized in the Chesapeake Bay in heavy winds and choppy waters, Maryland Marine police reported yesterday.

Police said they began searching the waters along North Beach in Calvert County Sunday afternoon after receiving reports of an empty boat.The bodies of Paul C. McGrath, 28, of 7818 Eagle Ave., Alexandria and his daughter Taris, 8, were found at about boat had been spotted.

Yesterday morning the body of the boat's owner, Paul P. McGrath, 58, of Suitland, was washed ashore in the North Beach area.

The North Beach accident happened during an afternoon filled with boating mishaps caused by blustery winds which developed at midday after a calm morning, Marine police reported.

"We had an usually large number of capsizings, boats running around and boats running into each other on Sunday," Purnell said. "That often happens when a day starts out calmly and then the wind kicks up."

Police said the three McGraths had planned to spend the day fishing and had taken the boat by trailer from Suitland to the North Beach area.

Purnell said the McGraths were last seen by other fishermen at about 2:30 p.m. Their empty boat was spotted and reported about one hour later.

Paul C. McGrath and his daughter were found in the same general area later that afternoon. They were pronounced dead on the scene, Purnell said.

Police said they believe that the small boat capsized in the heavy winds and all three victims were overwhelmed by the large waves once they were in the water.

According to the police, Paul P. McGrath, the boat's owner and his son had constructed the plywood vessel together.