Stuart Eizenstat has been appointed to the board of directors of Hercules Inc., a Wilmington, Del., chemical products manufacturer. Eizensat is a partner in the Washington law firm of Powell, Goldstein, Frazer & Murphy, and was chief domestic policy advisor to former President Jimmy Carter.

Harold Hollenbeck, Dawson Mathis, James Roosevelt and Lawrence S. Hoffheimer have been named senior associates of Jack McDonald Associates Inc., a government affairs consulting firm. Richard Kessler was named executive assistant. Hollenbeck and Mathis were former members of Congress, New Jersey and Georgia respectively. Roosevelt is a member of the President's Commission on Executive Change and a former California congressman and a U.S. representative to the United Nations Economic and Social Council. Hoffheimer was formerly chief counsel of the Community Relations Service of the Department of Justice. Kessler was formerly executive director of the Ripon Society, a research and policy organization affiliated with the Republican Party.

William Spartin has been named president of U.S. operations of MSL International Ltd. in Washington. MSL, an executive search firm, recently relocated its head office from Atlanta to Washington. MSL maintains six offices in this country. Spartin formerly served as a deputy director of presidential personnel at the White House. He was also formerly a managing partner of Paul Stafford Associates here and vice president of administration and assistant to the president of The Washington Post.

John T. O'Neill has been named vice president of marketing and business development of United States Service Industries in Washington. O'Neill was formerly executive vice president of the Apartment and Office Building Association.

Hal Chambless has been named marketing manager for international travel services of Ruesch International, the Washington foreign exchange and precious metals dealer.

Paul R. Gates has been named vice president of MMM Design Group, a Norfolk architectural and engineering firm. Gates is a retired Navy rear admiral.

Stephen P. Doyle has been appointed vice president for development of Association Management Inc.

Jerry D. Stump has been named vice president for operations of Snider Engineering Inc. in McLean.

Gary M. Frank has been promoted to vice president of Capital Credit Corp. He was formerly general manager of the Washington office.

Jerry L. Kilcrease has been named manager of the naval architecture division of Advanced Marine Enterprises Inc. in Arlington. Kilcrease was formerly vice president of commercial ship engineering of Levingston Marine Corp.

Harold Jordan has been named vice president and general counsel of Automated Business Systems & Services Inc. in Hyattsville.

Alan Secrest has been named senior project director of the Market Research Bureau Inc. Secrest was formerly senior analyst of Peter D. Hart Research Associates, a Washington political research firm.