Mr. Blackwell was a founder in 1975 and later served as commodore of the Dolphin Cruising Club, Baltimore's only black yacht club, which was part of the Federation of Black Boaters based in Jamaica, N.Y.
In 1978, the couple were instrumental in the chartering of Flotilla 19 of the Coast Guard Auxiliary in Baltimore. He was the flotilla's first commander and attained Coast Guard Auxiliary retired status.
Mr. Blackwell also liked to take cruises and traveled by steamship to Bermuda and the Caribbean.
"Bo could sometimes seem quiet and reflective, but he was always up for a good time and enjoyed life with gusto," his granddaughter said. "He was never one to hold back an opinion and advice or turn down an offer of crabs and a cold beer."
His wife of 54 years died in 2003, and in recent years, he lived with his daughter in Ellicott City.
"He lived an amazing life. He was born of a young mother, raised in a rural community by his grandparents, and against all odds, became a public servant, earned a college degree, traveled all over the world and lived to know his great-grandchildren," said his daughter, Dr. Jacalyn Blackwell-White, a pediatrician.
Mr. Blackwell was a member of Palm Coast United Methodist Church in Florida.
He was also a member of St. John Baptist Church, 9055 Tamar Drive, Columbia, where services will be held at 2:30 p.m. Sunday.
In addition to his daughter and granddaughter, Mr. Blackwell is survived by two brothers, Charles Gray and Joseph Gray, both of Baltimore; another granddaughter; and three great-grandchildren.