The Balao-class submarines were a series of submarines built for the United States Navy during World War II. They were designed to improve upon the earlier Gato-class submarines, featuring a longer hull and increased diving depth. A total of 120 Balao-class submarines were constructed, making them one of the most numerous classes of submarines in history. These submarines were equipped with advanced sonar and torpedo systems, allowing them to effectively engage enemy ships and submarines. The Balao-class played a significant role in the Pacific Theater, contributing to the success of the U.S. Navy in naval warfare during the war.