The crew's hope for survival dropped when an enemy submarine's periscope was reported off the port bow. Japanese submarines aggressively penetrated Allied defensive screens and torpedoed carriers more than once during the war, and the enemy boat, if such she was, maneuvered in a perfect position to pick of a carrier as one passed on its enforced course. "Kitkun Bay" swung over to 205° to present as small a target as possible and enable the escorts to attack the submarine. One of the Avengers claimed to sight the periscope and dived on it, the pilot later expressing his belief that his depth charges sank the submarine. A puff of reddish smoke and the green dye marker that the plane dropped revealed the only evidence of the submarine, and "Kitkun Bay" passed almost over the spot where the lookout first sighted the periscope. The elusive submarine, if one indeed ever prowled the area, vanished without a trace.