Convert from mark twain to arsheen [Russia]

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 (arsheen [Russia])
The Arsheen, also called the Archin, Archine, Archinne, Arschine and Arshin. In the early 18th century, the Tsar Peter the Great issued a ukase redefining the traditional Russian units of length in terms of the English foot. The archin was made equal to 28 English inches, 71.12 centimeters or 16 Vershki.