Convert from mark twain to rute [Germany]

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 (rute [Germany])
The rute is a traditional German unit of distance corresponding to the English rod. In fact, "rute" is the German word for rod. The rute had varying lengths, as short as 10 fuss (German feet) and as long as 16 fuss. This could be anywhere from about 3 meters to 4.5 meters.