Convert from fother [lead] to decitonne

Unit Definition (fother [lead])
The fother is a traditional English unit of weight for lead. The fother, equal to 30 fotmals, was always a little smaller than a (long) ton. The original version seems to have been equivalent to 2160 avoirdupois pounds, and the version still being used in the nineteenth century was equal to 19.5 hundredweight or 2184 pounds.

Unit Definition (decitonne)
The decitonne is a metric unit of mass or weight equal to 100 kilograms (approximately 220.4623 pounds). This unit is becoming common in international trade; it is the same as the Russian centner, the German doppelzentner, and the French metric quintal.