For extraordinary heroism following internal explosion of the Florence H, on 17 April 1918. The sea in the vicinity of wreckage was covered by a mass of boxes of smokeless powder, which were repeatedly exploding. Frank M. Upton, of the USS Stewart, plunged overboard to rescue a survivor who was surrounded by powder boxes and too exhausted to help himself. Fully realizing the danger from continual explosion of similar powder boxes in the vicinity, he risked his life to save the life of this man.