A visitor flying into Philadelphia International Airport, Pennsylvania, may not realise they have landed on the site of what was briefly the world's largest shipyard and the birthplace of 122 emergency cargo ships.
In February 1917, as the First World War entered its third year, Germany commenced unrestricted submarine warfare and by the middle of the year, merchant shipping losses had become enormous (see Table 1 below). There was an urgent need to replace as many of the lost ships as quickly as possible, though with the introduction of convoys for merchant ships towards the end of 1917, the threat was significantly reduced.
America entered the war in April 1917 and came up with a plan that entailed building a brand-new shipyard to supply much-needed tonnage in as standardised a design as possible. The resulting vessels would become known as Hog Islanders in acknowledgement of where the new yard would be established.
A simplified design
The vessel designs that were built were produced by the Emergency Fleet Corporation, established in April 1917 to "acquire, maintain, and operate merchant ships to meet national defence, foreign and domestic commerce during the First World War” with plans to build 2,316 ships.
The Hog Island ships would be the cornerstone of this plan. Type A (1022) would be a cargo ship while the Type B (1024) was designed as a troop transport. Both designs were simplified for ease of construction rather than appearance and, as an example, lacked any sheer in the hull. Nevertheless, they were very modern for their day being steam turbine powered with three oil-fired boilers.
Largest shipyard in the world
A huge shipyard was constructed by American International S.B. Corp. on Hog Island on the Delaware River, just below Philadelphia. When completed the shipyard covered more than 900 acres and stretched for two miles along the riverfront. Facilities included 250 buildings, 50 slipways, seven wet docks, and a railroad 4.5 miles in length, with marshalling yards connecting it to Philadelphia, and numerous cranes; making it the largest shipyard in the world at the time.
The ships themselves would be prefabricated at other sites to speed up construction, this representing a new approach to shipbuilding. Initially a total of 180 vessels were ordered from the yard, though in the end production stopped at 122 units; of which 24 were Type B troop ships, 12 with a displacement of 8,400 tonnes and the remainder displacing 13,400 tonnes.
Following the last delivery, the yard was closed and then demolished. Two of the locomotive steam gantry cranes were sold as surplus to the city of Trenton, New Jersey, where they remain today as the Hog Island Cranes, listed on the National Register of Historic Places. By 1925 the site had become a training airfield for the local National Guard and then in 1927 the airport for Philadelphia although the first proper terminal was not constructed until 1940.
Careers of the Hog Islanders
Despite the intention of easing the wartime shipping crisis, ironically the first vessel completed by the yard, the Quistconck, was not delivered until 3rd December 1918, some three weeks after the Armistice was agreed that ended the First World War. Construction had taken 1,160,000 man-hours as the shipyard was itself still under construction; however, the second ship required 601,000 man-hours and the third only 400,000 man-hours.
Production continued after the war to meet the demand for replacement ships and the last ship, the Skanawono was completed in January 1921. The ships operated throughout the following years and saw much service, both civil and military, throughout the Second World War during which 58 Hog Islanders were lost. Those that survived lived on into the post-war era with, for example, the Quistconck not being scrapped until 1953 after 35 years service. The last Hog Islander was scrapped in 1971.
Though not constructed in the numbers that the Second World War's Liberty ships would be, the Hog Islanders demonstrated the effective designs and advanced methods of construction that would prove invaluable many years after their conception.
Gross tonnage sunk by German submarines during 1917
Hog Islander Type A (1022) typical particulars
John Barnes is a journalist and author and former editor of Marine Engineers Review.