Slaving ships varied in size, shape and weight, depending upon where they primarily traded and travelled. In Lancaster the ships were usually smaller, since it was a river port and the vessels needed to navigate the Lune estuary. Typically, the slave ships were built in Lancaster by local industrialists such as the Brockbanks, and crewed by a small group of young men from the town seeking adventure or a reasonable wage in hard times. The vessels were financed by local merchants and tradesmen who could buy shares in the ship or voyage.
Most Lancaster vessels were Brigs or Snows, weighing 20 to 100 tons, although most were 20-70 tons and of 40 to 50 ft in length. While this meant the ships could carry fewer slaves than those of Liverpool, London or Bristol, they were well-suited for navigating the Windward Coast, entering the River Gambia and traversing African estuaries where slaving was more specialist. Furthermore, less time spend along the African coast meant the risk of contracting tropical diseases and of slave revolts was reduced.