The Coast Guard contracted for seven modified Hall PH-1 flying boats. This type of amphibian aircraft was originally developed for the Navy as a patrol aircraft. The upgraded flying boats purchased by the Coast Guard and delivered in 1938 had more powerful engines as well as more specialized equipment and capabilities for search and rescue duties. They were were given the designation PH-2. They were the largest aircraft ever acquired by the Coast Guard to that time. In 1939 the Coast Guard ordered seven more upgraded Hall flying boats and these received the designation PH-3.
After the Japanese attack on Pearl Harbor the Hall flying boats were given the standard Navy livery in place of the aluminum paint configuration. They were pressed into service for ant-submarine patrol. Initially unarmed they were modified by Coast Guard personnel to enable them to carry depth charges. They were utilized extensively to direct surface vessels to survivors of torpedoed ships and on a number of occasions they set down in the sea to make a rescue. Prior to the end of the war they were replaced by PBY and PBM aircraft.
