 Hubbard stated in his eighteen-page after-action report that he had intended to force the submarine to surface so that it could be attacked by the surface vessels'guns. He reported that his vessel had seen oil on the surface, though the PC-815 took no samples, and asserted that the blimps had seen air bubbles, oil and a periscope, though the blimps' own reports did not corroborate this. No wreckage was seen, despite the heavy depth-charging. The PC-815 sustained some minor damage and three crew were injured during the incident when the ship's radio antenna was accidentally hit by gunfire. At midnight on 21 May, with depth charges exhausted and the presence of a submarine still unconfirmed by any other ship, PC-815 was ordered back to Astoria.
