Quite untrue. The Americans had many submarines. They were used primarily against the Japanese to great effect. Strangling the supply line from Southeast Asia. Especially oil from Brunei.
It was so effective that Admiral Halsey testified on behalf of Admiral Doenitz at Nuremberg. Saying what Doenitz was trying in the Atlantic, the US was successful at in the Pacific. Doenitz still got ten years in prison for ordering U boat crews to kill floating survivors of attacks.