Convert from mark twain to cape inch

Unit Definition (mark twain)
The mark twain or twain is an old word for the number two, derived from the Anglo-Saxon twegen. The American author Samuel Clemens (1835-1910), who had been a riverboat pilot on the Mississippi in his youth, took his literary name from a traditional riverboat phrase "mark twain", meaning "exactly two" fathoms of water. This was the minimum depth needed for the boats to operate safely without running aground.

Unit Definition (cape inch)
The cape inch is another traditional South African unit for distance. There are 12 cape inches in a cape foot. The Cape foot equals 12.396 English inches, 1.0330 English foot, or 31.4858 centimeters.