Frank J. (Fritz) Jancar, 65, a Navy chief photographer's mate during World War II who later worked as a civilian photographer for the Navy, died Monday at Suburban Hospital in Bethesda after a heart attack.

During World War II Mr. Jancar was assigned to the Office of Strategic Services (OSS) in China, India and Australia as a Navy chief photographer's mate.

After the war, he went to work as a photographer for the David W. Taylor Model Basin at the Navy's Ship Research and Development Center at Carderock, along the Potomac River in Montgomery County.

Mr. Jancar was skilled in underwater and high-speed photography. At the basin, models of nearly every major naval and merchant ship had been tested for performance during the last 38 years. He retired in 1977.

He had received an award of appreciation from the basin's scuba divers.

Mr. Jancar was born in Lorain, Ohio. A resident of Cabin John, he had lived in this area for 35 years.

He was active as an amateur radio operator whose call letters were W3SQB.

Survivors include his wife, Mary B., of Cabin John; a daughter, Sheila St. Clair of Germantown, Md., a son, Frank, of Cabin John; a brother, Rudolph V., and a sister, Agnes Bucher, both of Lorain, and a sister, Albina Uehlein of Sheffield Lake, Ohio.