William Shofnos, 76, a retired official of the National Ocean Survey, a division of the National Oceanic and Atmospheric Administration, and a specialist on tides and long-period sea level variations, died of lymphoma Friday at Sibley Memorial Hospital.

In 1926, Mr. Shofnos, a civil engineer, joined the water level division of the old Coast and Geodetic Survey, which became part of the National Oceanic and Atmospheric Administration in 1970. He later transferred to the oceanographic division of the NOAA's National Ocean Survey and served as deputy chief of the division from the mid-1950s until his retirement in 1973.

Besides his work on currents, tides and tidal predictions, Mr. Shofnos was involved with the legal aspects of coastal and marine boundaries for the National Ocean Survey.

A native of Washington, he earned a bachelor's degree from the University of Maryland's school of engineering. He also earned a law degree from Georgetown University law school.

He was a member of the American Society of Civil Engineers and had written a number of articles in his field for professional scientific journals. wHe lived in Washington.

Survivors include his wife, Jeannette C., of Washington; a brother, Maurice, of Chevy Chase, and three sisters, Mollie Harris of Hyattsville, and Isabel Kaufman and Lee Weinberg, both of Silver Spring.

The family suggests that expressions of sympathy be in the form of contributions to the Parkinson's Research Fund at Georgetown University.