Hog chains

Hog chains were a technological device that permitted river boats to have lightly built hulls so they could travel in shallow water.

[1] These were not chains at all, but rather iron rods 1 to 2.5 inches (25 to 64 mm) in diameter, which ran from strong points in the hull to vertical timbers, called "hog posts", which looked like masts, rising above the hull.

[1] Generally the hog posts which carried the chains did not rise above the cabins on Mississippi River-style steamers.

[1] This was not the case with steamboats designed in the Pacific Northwest style, where the hogposts were often clearly visible rising above the superstructure.

In some cases the sagging on the ends would be so great that a boat's hull would break in half.