Ralph E. Casey, 70, a former executive vice president of the American Institute of Merchant Shipping and an advocate for a strong U.S. merchant marine, died of cancer Feb. 23 at his home in Point Clear, Ala.

Mr. Casey, a lawyer, had a long career in government as well as serving as a spokesman for merchant shipping interests. He was a partner in the Washington office of the law firm of Haight, Gardner, Poor & Havens, which is based in New York, from 1972 until 1981, when he retired and moved to Alabama.

A native of Boston, Mr. Casey earned bachelor's and law degrees at Harvard University. He moved to Washington in 1939 as an auditor with the General Services Administration. From 1955 to 1956, he was chief counsel of the House Merchant Marine and Fisheries Committee.

In 1956, he was elected president of the American Merchant Marine Institute, a trade organization representing 70 percent of the U.S. merchant marine industry. In 1969, that group merged with the American Institute of Merchant Shipping. Mr. Casey was executive vice president of the new organization until 1970.

He then returned to the staff of the House Committee on the Merchant Marine and Fisheries. He joined Haight, Gardner two years later.

Survivors include his wife, Virginia, of Point Clear; a son, Richard, of Mobile, Ala.; two daughters, Barbara Ruffino of Hingham, Mass., and Elizabeth Herold of Huntington, N.Y.; two brothers, Warren, of Boston, and Howard, of Kings Point, N.Y., and eight grandchildren.