After the Japanese attack on Pearl Harbor on 7 December 1941, the submarines of the Asiatic Fleet were the primary striking force available to Admiral Thomas C. Hart, the fleet's commander. He was assigned sixteen "Salmon"s or "Sargo"s; the entirety of both classes. Seven "Porpoise"-class and six S-boats rounded out the force. The Japanese did not bomb the Philippines until 10 December 1941, so almost all of the submarines were able to get underway before an attack. "Sealion" and "Seadragon" were the unlucky exceptions. In overhaul at the Cavite Navy Yard, "Sealion" was damaged beyond repair and was scuttled on 25 December. "Seadragon", assisted by and , was able to leave port with emergency repairs and went on to fight for most of the war.