In America’s steamboat era, the main danger to waterborne travel and commerce was neither fire nor explosions, but rather snags—trees that had fallen into the rivers as a result of bank erosion. The current carried them to the center of the stream, and the heavier end, that with the roots, became lodged in the riverbed with the other end pointed downstream at an angle. A snag could punch a hole in a boat’s hull, often causing it to sink. Particularly dangerous were the fallen trees that lay hidden beneath the river’s surface. Snags caused enormous losses of vessels, cargoes, and lives.
During an age when America moved mostly by water, the Corps of Engineers began removing snags and other obstructions on navigable rivers in 1824. [More...]