They were aggressive and effective .
The submarine skippers of the fleet boats of World War II waged a very effective campaign against Japanese merchant vessels , eventually repeating and surpassing Germany 's initial success during the Battle of the Atlantic against the United Kingdom .
submarine skippers were aggressive and effective .
The submarine skippers of the fleet boats of World War II waged a very effective campaign against Japanese merchant vessels , eventually repeating and surpassing Germany 's initial success during the Battle of the Atlantic against the United Kingdom .