By December 1941, Finn was stationed at Naval Air Station Kaneohe Bay on the island of Oahu in Hawaii. As a chief aviation ordnanceman, he was in charge of twenty men whose primary task was to maintain the weapons of VP-11, a PBY Catalina flying boat squadron. At 7:48 a.m. on the morning of Sunday, 7 December 1941, Finn was at his home, about a mile from the aircraft hangars, when he heard the sound of gunfire. Finn recalled how a neighbor was the first to alert him, when she knocked on his door saying, "They want you down at the squadron right away!" He drove to the hangars, catching sight of Japanese planes in the sky on the way, and found that the airbase was being attacked, with most of the PBYs already on fire.