1940s footage of a US Navy submarine sinking a Japanese merchant ship during World War II

VS man at submarine periscope's viewfinder and POV ship seen above through the scope; ship's commander at scope barks order; huge ship explosion seen through scope and shirtless sailors at controls; periscope; sailor presses trigger of torpedo that skips just under ocean surface and resulting explosion on the Japanese merchant ship / commander flips up handles of scope / VS submarine rises from under the water / VS manning guns atop ship; heavy fire directed at bow of Japanese fishing boat that then explodes and burns on horizon / Note: exact year not known