Retired Adm. Arthur Dewey Struble, 88, who served as U.S. naval chief of staff for the Normandy invasion during World War II and who later, as commander of the 7th Fleet, directed the Inchon landing during the Korean War, died of pneumonia May 1 at his home in Chevy Chase.

During a 41-year naval career of unusual diversity that spanned three wars, Adm. Struble served in virtually every type of surface vessel and in staff and diplomatic posts ranging from instructor at the U.S. Naval Academy to U.S. naval representative to the United Nations.

But it was in the planning and execution of the two key amphibious landings that the diminutive fleet commander played his largest role in history.

As chief of staff to the Western Naval Task Force on June 6, 1944, he was awarded the Legion of Merit "for exceptionally meritorious conduct previous to and during the amphibious assault" on the German-held coast of Normandy, an assault that he had helped plan during a year of duty in London.

Six years later the Army awarded him the Distinguished Service Cross for "extraordinary heroism" as commander of U.S. naval forces in the Far East during the invasion that changed the course of the Korean War.

Working closely with General of the Army Douglas MacArthur, the supreme commander of allied forces in the Pacific, Adm. Struble planned and directed the neutralization of shore batteries and mine fields protecting Inchon harbor, and put ashore nearly 70,000 troops in what historians have labeled one of the classic flanking maneuvers of military history.

Citing his "conspicuous courage," "brilliant tactical operations" and "bold execution of plans," the citation said "the Inchon invasion, one of the most difficult ever attempted because of extreme tides, was brilliantly effected with minimum loss of landing forces."

A native of Portland, Ore., Adm. Struble graduated from the Naval Academy at Annapolis in the class of 1915 and served on the destroyer Stevens on antisubmarine duty off Ireland during the last months of World War I.

After a variety of shore and sea posts between the wars, he assumed command of the cruiser Trenton, and was patrolling off Panama at the outbreak of World War II.

After his service in London before and after D-Day, he was transferred to the Pacific to command successive amphibious assaults in the Philippines, including the initial landings in Leyte Gulf and Mindoro.

Adm. Struble retired in 1956, and later was a special adviser to the Hamilton Watch Co. and a director of the New York Shipbuilding Corp.

In addition to the Distinguished Service Cross he received for Inchon and the Legion of Merit he received for Normandy, his decorations included two Distinguished Service Medals from the Navy and one from the Army, two other Legions of Merit, and the Navy Commendation Medal. He also received decorations from Belgium, France, Greece, China and Korea.

His first wife, the former Hazel L. Ralston, died in 1962.

He is survived by his wife, the former Margaret Avery Ringle, of Chevy Chase and Avery Island, La.; three children by his first marriage, retired Navy Cmdr. A.D. Struble Jr. of Palos Verdes Estates, Calif., Nancy Wilhite of Fort Sumner, Md., and Elizabeth Wilson of Chevy Chase; eight grandchildren, and 10 great-grandchildren.