Convert from shaftment to arpent [France]

Unit Definition (shaftment)
A shaftment, when used as a unit of length, is usually six inches or two palms, i.e. 15.24 cm (for the international inch). It is thought to be the distance from the tip of the outstretched thumb to the other side of the palm.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (1/8 shaftment), finger (7/48 shaftment), palm (½ shaftment) hand (2/3 shaftment), span (1½ shaftments), cubit (3 shaftments) and ell (7½ shaftments).

Unit Definition (arpent [France])
The Arpent is a traditional unit of distance in French-speaking nations. It was used as a land measurement, which is the reason for 'Arpentage' becomming the French word for surveying. It has an official definition of 191.835 English feet (58.471308 meters).