William “Wat” Stewart, a retired manager at Acacia Mutual Life Insurance who was passionate about promoting a cappella singing, died Jan. 22  at his home in Kensington of congestive heart failure. He was 88.
Mr. Stewart was a human resources training manager at Acacia for about 20 years until retiring in 1990. Earlier, he did managerial work in Detroit and New York for Home Life Insurance Co.
In his free time, he enjoyed singing as a second tenor in the Augmented Eight, a men’s a cappella group in Washington. In 1957, he founded the Spring Sing, an annual gathering of a cappella groups from around the country that continues today under the auspices of the American A Cappella Alliance.
Mr. Stewart was instrumental in gathering a collection of a cappella sheet music and recordings to donate to the Library of Congress.
William Watson Stewart was born in Belleville, N.J. He served in the Army in Italy during World War II and graduated from Princeton University.
He volunteered with the Kensington Historical Society, helping to found and direct an outdoor summer concert series and working to preserve historic homes from development.
He was a member of Chevy Chase Presbyterian Church.
Survivors include his wife of 66 years, Mary Pitcher Stewart of Kensington; four children, Sally S. Gilbert of Takoma Park, Elizabeth T. Stewart of Kensington, John W. Stewart of New York and David S. Stewart of Denver; and three grandchildren.