On May 11, 1898, Seaman Foss, together with other sailors from the USS Marblehead and the USS Nashville, grappled up two undersea telegraphic cables from the ocean floor off Cienfuegos, Cuba onto the bows of two longboats towed within 100 feet of the enemy shore and proceeded to sever those thick, lead-encased cables with axes, cold chisels, and hacksaws. During the entire three-hour operation, Foss and his shipmates were under continuous enemy fire from Spanish rifle pits dug into the beach, resulting in the deaths of two sailors and the serious wounding of several others.
Seaman Foss further distinguished himself aboard the USS Marblehead during the Battle of Santiago de Cuba on July 3, 1898. The Treaty of Paris formally ended the Spanish-American War on December 10, 1898, and dissolved the former Spanish colonial empire.
On July 7, 1899, Seaman Foss was awarded his country’s highest military honor, the Medal of Honor, for his extraordinary bravery and coolness under enemy fire. A piece of one of the cables he had helped sever was also presented to him. Foss also earned the following medals:
- Admiral Sampson Navy Medal, 1898
- West Indies Campaign Medal, 1898
- Good Conduct Medal, 1898
- Spanish War Veterans Medal, 1899