During Prohibition, smugglers sailed the waters between Canada and the Caribbean to bring illegal contraband to the United States. Captain William McCoy is credited with the idea of bringing large boats just to the edge of the three-mile (4.8 km) limit of U.S. jurisdiction and selling his wares there to “contact boats,” typically local fishermen and small-boat captains. The small quick boats could outrun Coast Guard ships and dock in any small river or eddy, and transfer their cargo to a waiting truck. The three-mile limit became known as the “Rum Line,” with the ships waiting called “Rum Row.” By far the biggest Rum Row was between New Yorkand Philadelphia, off the New Jersey coast, where as many as 60 ships were seen at one time. New Jersey rum runners could be seen at night running into remote areas in Raritan Bay in flat-bottom skiffs for running up on the beach, making a delivery, and speeding away. These bootleggers typically used a modified Sea Bright skiff or a Jersey Skiff, smallcraft converted into speedboats, able to be launched into heavy surf and safely return to shore, outrunning Coast Guard cutters.
On April 21, 1924, the Rum Line was extended to a 12-mile (19.3 km) limit by an act of the United States Congress, which made it harder for the smaller and less seaworthy craft to make the trip, and enforcement of Prohibition became more effective.
Sources: Burns, Eric (2004). The Spirits of America: A Social History of Alcohol. Philadelphia, PA: Temple University Press. p. 215