Convert from shaftment [ancient] to wah [Thailand]

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 (wah [Thailand])
The wah is a traditional unit of distance in Thailand, now aligned with the metric system as exactly 2 meters (6.562 feet). This unit is the Thai version of the fathom. It is seen mostly in connection with the talangwah or square wah (4 square meters or 4.784 square yards), a common unit of area in Thailand.