Convert from seer [India] to keel [coal]

Unit Definition (seer [India])
The seer [India] is a traditional weight unit in India and South Asia. The seer equals 1/40 maund, and, like the maund, it varied considerably from one area to another. The official size in British India was 2.057 15 pounds or 0.9331 kilogram. The unit is sometimes spelled ser.

Unit Definition (keel [coal])
The keel is a traditional British unit of weight for coal. After considerable variation, the keel of coal was standardized in 1695 as 21.2 long tons, or 47 488 pounds (21.5402 metric tons). This is the approximate weight of coal carried at that time by barges on the river Tyne in northern England; the barges were also called keels, from the Dutch word kiel for such a ship.