Harlan & Hollingsworth's expanded slowly but steadily into iron shipbuilding. Only nine ships were built between 1841 and 1851, with most of the company time taken with railroad car building and general repair work. In 1843 the company leased a launching berth on the banks of the Christiana River. The facilities at this property were limited, so all the work forming iron plates, bars, and fasteners was done at their main shop on Front and West Streets. The launch slipway was 200 feet long and could only accommodate vessels of 600 tons maximum, but this was deemed adequate for the needs of the time.