Thomas D. Hobart III, a senior federal executive and deputy assistant commander of the Naval Electronic Systems Command from 1966 until his retirement in 1986, died Aug. 3 at Mount Vernon Nursing and Rehabilitation Center in Alexandria. He was 93.

The cause was complications from a heart ailment, said a son, Duncan Hobart.

Mr. Hobart, an engineer, spent more than 40 years as a federal employee and developed an expertise in Navy shipbuilding and weapon system programs.

In retirement, he volunteered as an IRS income tax preparer in Fairfax County for 15 years.

Thomas Duncan Hobart III was a native of Roanoke and a 1941 electrical engineering graduate of Virginia Tech. He was an electronics engineer at the Naval Research Laboratory in Washington during World War II. He joined the Navy’s Bureau of Ships in 1946.

He was a graduate of the Federal Executive Institute in Charlottesville, the Industrial College of the Armed Forces at Fort McNair in Washington, and the Harvard Business School.

He received the Navy Superior Civilian Service Award.

Mr. Hobart, a resident of the Alexandria area of Fairfax County, was a volunteer leader with the Boy Scouts of America and received the Silver Beaver Award and the Wood Badge award.

His wife of 61 years, the former Rose Mazzara, died in 2006. Their son Charles Hobart died in 1965.

Survivors include three sons, Robert Hobart of Fairfax Station, and David Hobart and Duncan Hobart, both of Alexandria; a sister, Helen Hobart of Alexandria; and two granddaughters.

— Adam Bernstein