During the Philippine–American War, "Yorktown" stood in to Baler Bay, on the west coast of Luzon, on 11 April 1899, on a mission to relieve a Spanish garrison that had been under siege by Filipino troops for nine months. Lt. James C. Gillmore and a party of sailors in the ship's whaleboat provided a decoy, ostensibly taking soundings of a nearby river. Meanwhile, Standley and an enlisted man landed farther up the coast to reconnoiter. The next day, Gillmore and his boat crew drifted into a trap, running aground too far from the river's mouth and out of sight of "Yorktown". Filipino troops, hidden in the jungle-covered banks, raked the boat with rifle fire. Two American sailors were killed; two were mortally wounded; and the remainder, including Gillmore, were slightly wounded. The survivors were taken prisoner until freed by U.S. Army troops. Standley completed his mission and, together with the enlisted signalman, made it back to the ship.