Convert from slinch to keel [coal]

Unit Definition (slinch)
The slinch is a unit of mass invented by the U.S. National Aeronautics and Space Administration (NASA). The unit is part of a system based on the pound of force and the inch. One slinch is the mass accelerated at one inch per second per second by a force of one pound; thus the slinch equals exactly 12 slugs or about 386.088 pounds (175.1268 kilograms). The word is a contraction of slug-inch. In the U.S. military aircraft industry, this unit is sometimes called a mug. It has also been called a snail.

Unit Definition (keel [coal])
The keel is a traditional British unit of weight for coal. After considerable variation, the keel of coal was standardized in 1695 as 21.2 long tons, or 47 488 pounds (21.5402 metric tons). This is the approximate weight of coal carried at that time by barges on the river Tyne in northern England; the barges were also called keels, from the Dutch word kiel for such a ship.