The total toll on American life was huge, 2,390 are killed and 1,179 are wounded. The vast majority are Junior enlisted personnel, a few years out of High school. 49 civilians lost their lives to friendly fire. The Japanese lost just 65 men.
Underwater footage of the Japanese mini subs in eps 1 and 2 is actually the FX shot of the Russian Akula class from the movie Hunt for Red October.