In early periods of North American industrial development, an ark was a temporary boat used for river transport in eastern North America before slack-water canals and railroads made them obsolete. Because they could be built using relatively crude hand tools, arks were built in American colonial and early republic times, primarily to carry cargo downriver on the spring freshets, and especially to carry milled lumber, charcoal and other forest products and bulk agricultural produce to a city or a port downriver. While logs were often tied into rafts, on long trips which could take weeks, the rafts would be accompanied by such arks as crew support quarters. Deep rivers allowed large log arks as described below instead of less controllable rafts. Since by 1800, most eastern towns and cities were short on heating fuels, even badly processed timber or planks could readily be sold at the destinations.