the Hall PH flying boats, with a different hull fitted with an enclosed cockpit, and some of these remained in service until World War II. Operational history The early prototypes of PN sea planes were used in a series of long-distance flights. During the afternoon of 31 August 1925, an attempt was made to fly a pair of PN-9 planes non-stop from San Francisco to Hawaii, a distance of nearly 2,400 miles (3,864 km) — a trip anticipated to take 26 hours to complete. The first plane to start was forced to land outside of San Francisco due to a failure of oil pressure, with the crew rescued by the destroyer USS William Jones and the aircraft towed back to port. The second PN-9 to depart, captained by U.S. Navy Commander John Rodgers, flew before running out of fuel when anticipated tailwinds that would have slowed gasoline consumption did not materialize. The plane was unable to make contact with the naval airplane tender USS Aroostook, a ship stationed along the PN-9's flight path and was forced to land at sea when both engines stopped functioning. With power lost, the plane was unable to send or receive radio signals. Although this was at the time a new distance record for seaplanes, the plane remained hundreds of miles short of the nearest landfall and the situation of the crew, with limited quantities of food and water, appeared dire. Since seas were moderate, the decision was made to attempt to sail the plane to Hawaii. The crew then rigged crude sails made from fabric torn from the aircraft's wings and sailed the aircraft a further , finally being spotted on the ninth day about off the southeast coast of the Hawaiian island of Kauai. In the aftermath of the headline-grabbing rescue, Commander Rogers was promoted to the position of Assistant Chief of the Navy's Bureau of Aeronautics. PN-9 No. 1, the same plane sailed to Hawaii, did not fare as well, later ditching in the Caribbean Sea during an attempted long-distance flight to South America and subsequently sunk as a navigation hazard. The two PN-12s were also used to set various records, including range and speed over circuit records. The various production derivatives of the PN-12 entered service with the US Navy from 30 April 1928, when VP-7D received its first Douglas PD-1, remaining in service until July 1938, when the last Keystone