Miah Maull Shoal Lighthouse, Delaware Bay New Jersey
The Miah Maull Shoal Lighthouse is a well-preserved embodiment of the cast-iron and concrete caisson foundation technology which was used from 1876 to 1913 in lighthouses that occupied waterbound sites in the northeastern United States. At least 50 such lighthouses were built. Miah Maull Shoal, designed in 1907 and completed in 1913, was the last example of this type built before reinforced concrete technology was introduced; it was also one of the last major navigational aids built in the Delaware Bay. As part of a string of lighthouses in the bay and the lower Delaware River that were in place before World War One, Miah Maull Shoal helped foster the improved navigation of the Delaware that was crucial to the success of the Hog Island Shipyard (now the site of the Philadelphia International Airport), which was established in 1917. By the end of the conflict, Hog Island had become the largest shipyard in the world.
The Miah Maull Shoal itself, which was named for an eighteenth-century Delaware mariner, was 800 yards wide and 3,000 yards long at a depth of 13 feet — a significant hazard to large modern ships, which required a much greater draft. The need for a deep channel, both for commercial and for military purposes, was foreseen during the early years of this century. Now known as the Philadelphia Ship Channel, it was called for by Congress in the River and Harbor Act of 1909 to be a 35-foot deep channel at least 800 feet wide from the Philadelphia and Camden wharves and shipyards to the mouth of Delaware Bay, to replace an existing 600-foot wide, 26-foot deep channel begun in 1885. Subsequent improvements have deepened the channel to 40 feet.
Miah Maull Shoal Lighthouse was designed as one of the major navigational
aids required for this channel. Appropriations to build it were approved by
Congress in acts of June 30, 1906, March 4, 1907, and March 4, 1911. The
lighthouse was designed during 1907-08 to employ a pre-fabricated conical
cast-iron shell resting on a foundation of pilings surrounded by riprap. In
this method of construction, the shell was pre-fabricated, towed to the site,
and sunk by filling it with concrete. The contract for the shell was awarded
in May 1908 to the Lynchburg Foundry Company, of Lynchburg, Virginia, even
before site work began. The plates were delivered to Wilmington, Delaware,
where they were subsequently assembled and the shell floated. Work at the
site was started on July 24, 1908. The Coast Guard towed the shell to the
site in August 1909, and the sinking and filling was completed by November.
In June 1910, with the building's superstructure under construction,
Engineering News described the emerging edifice.
The foundation shell is 40 ft. in diameter at the base and 42 ft. 8 ins. in height. It is composed of 224 1+1/4-in. cast-iron plates in seven courses, the top course being bell shaped.... The superstructure will consist of a three-story iron dwelling....
The superstructure of Miah Maull Shoal Lighthouse was completed on February 20, 1913 and its permanent fog signal was placed in operation on December 5, 1913.
Less than one year later, the Great War erupted in Europe. As part of the American response, the United States commissioned a great number of new military vessels. In September 1917, after the American entry into the war, the American International Shipbuilding Corporation was awarded a contract to build fifty large cargo ships, and in the following month a subsequent contract added seventy more, all to be completed before the end of July 1919. To meet this extraordinary demand, the company secured Hog Island, a large island along the west shore of the Delaware River just south of the confluence of the Schuylklll River. In a crash construction program from September through December 1917, the company built the Hog Island Shipyard in order to fulfill its contract, which could not be handled by existing shipyards in the Delaware Valley. The ships produced by the Delaware River shipyards for World War One proved the need for the Philadelphia deep channel and its value for national security.