Between 1830 and 1915, lumber companies in western Wisconsin floated millions of pine logs and pieces of cut lumber down the Chippewa River into the Upper Mississippi River opposite this point, where they were assembled into huge rafts and sent downstream to mills in Iowa, Illinois, and Missouri. Some rafts held up to 10 million board feet of lumber, enough to build 500 houses, and the largest recorded raft, in 1869, covered 1.2 hectares (3 acres). Building these rafts was hard and dangerous work: crews fastened logs or lumber into wood frames called cribs, linked a dozen or more cribs into strings, and lashed several strings together to form a raft. Until the 1860s, the rafts were moved entirely by manpower, with two oarsmen on each string under the direction of a pilot; later, steamboats pushed the rafts from behind, often aided by a smaller boat at the front to steer. On some rafts, crews built a shanty for the cook and makeshift shelters for themselves, while on others they slept in tents.