Frank Jack Fletcher
Hubbard was sent to submarine chaser training, and in 1943 was posted to Portland, Oregon, to take command of a submarine chaser, the , which was under construction. On May 18, "PC-815" sailed on her shakedown cruise, bound for San Diego. Only five hours into the voyage, Hubbard believed he had detected an enemy submarine. Hubbard spent the next 68 hours engaged in combat, until finally receiving orders to return to Astoria. Admiral Frank Jack Fletcher, commander of the Northwest Sea Frontier, concluded: "An analysis of all reports convinces me that there was no submarine in the area." Fletcher suggested Hubbard had mistaken a "known magnetic deposit" for an enemy sub.