In December 1927, the U.S. Navy placed a contract with the Hall Aluminum Aircraft Corporation of Bristol, Pennsylvania for a developed version of the Naval Aircraft Factory PN-11,[1] which itself could trace a development history back to the Felixstowe F.5 flying boat of World War I.[2] The resultant prototype, the XPH-1, first flew in December 1929.[3]
The XPH-1 had identical wings and a similar metal hull to that of the PN-11, but was fitted with a large single fin and rudder. It was powered by two Wright Cyclone radial engines and accommodated its two pilots side by side in an open cockpit, with cockpits for gunners in the nose and behind the wings.[1]
In 1930 the Navy ordered nine aircraft, designated the PH-1, which were fitted with more powerful engines and a partly enclosed cockpit for the pilots.[4] The Coast Guard later ordered seven PH-2 aircraft, similar to the PH-1 but with armament removed, and seven PH-3 units with armament reinstated and a fully enclosed cockpit for the pilots.[1]
Delivery of the PH-1 commenced in October 1931,[1] equipping VP-8 from 1932, operating from the seaplane tender and from bases at Pearl Harbor, Midway Atoll, and the Panama Canal Zone. It was replaced by the Consolidated PBY-1 Catalina in 1937.[5]
Production of the PH recommenced in June 1936 to meet an order for seven PH-2s for the Coast Guard.[1] These entered service from 1938, being the largest aircraft operated by the Coast Guard at that time.[6] In 1939 the Coast Guard ordered an additional seven PH-3 aircraft; they entered service in 1941.[6]
The Hall flying boats were used by the Coast Guard for search and rescue duties and were fitted with specialized equipment for this role. Following the Japanese attack on Pearl Harbor and the United States entry into World War II, the remaining PHs were painted in U.S Navy Sea Grey to replace the previous silver paint, armed, and used for anti-submarine patrols (particularly during the Operation Drumbeat U-boat attacks off the East coast of the United States in 1942) as well as continuing search and rescue operations.[6] The Coast Guard continued operating the PH-2 and -3 until 1944.[6]
United States