Convert from shaftment [ancient] to pace [great]

Unit Definition (shaftment [ancient])
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 (pace [great])
A pace (or double-pace) is a measure of distance used by Ancient Rome. It is the measure of a full stride from the position of the heel when it is raised from the ground to the point he heel is set down again at the end of the step. In Rome this was standardized as about five Roman feet or 58.1 English inches.