The United States went into the war with something like thirty steel and twenty-four wood shipyards, employing less than eighty thousand men. In a little over a year's time, there were one hundred and fifty-five yards turning out ships and employing over three hundred and eighty-six thousand men. These men turned out more tonnage every month than the United States had ever turned out in any entire year before the war. Of the new yards, the greatest was the famous Hog Island yard. On what was once a swamp on the Delaware River, just below Philadelphia, the United States built this yard which is the largest in the world. The demand for speed in building resulted in the plan of fabricating the steel before sending it to the yards. By this method the steel is cut and punched before going to the yard where it is then assembled. Thus steel mills at long distances from the shipyards could be doing a very considerable part of building the ships. Perhaps the great increase in shipping can be best stated by a few figures. In the month of January, 1918, America produced 88,507 tons. Six months later in July she produced 631,944 tons. Before the war the official estimate of America's annual shipping production was 200,000 tons. The estimated production for 1919 was 7,500,000 tons.
The United States navy at the time of the declaration of war was unprepared for the task ahead of it. It was efficient but not nearly large enough for the tremendous amount of work it was called upon to perform. The troop and supply transports needed convoys. There were hundreds of miles of coast to be patrolled. Merchant ships must be armed with men and guns. All this had to be done, besides the work of aiding the Allied fleets in European waters. The government was not long in seeing the need of a great increase in the naval force and was soon making plans to bring this about. New yards were constructed immediately for the building of warships, and the capacity of the old yards was increased. These yards were soon busy turning out destroyers and battleships at a remarkable speed. The special work of patrolling the coasts for submarines called for a great many small and speedy submarine chasers. Motor boat manufacturers all over the country immediately began to make these swift little craft which were popularly called the "mosquito fleet." Even the great factories of Henry Ford, although already busy turning out thousands of motor cars, found room to build these chasers at their inland factories. They were built on specially constructed flat cars, which were then drawn to the coast, where the ships were launched.