Mary,
Good point, I agree with you. I always get lost with metric. The only issue is the temptation to round up when you get a fraction if you convert. For example when you convert 20sq meters to sq ft you get 65.6168. We dont want people telling their sailmaker that they want a 66 sq ft spin.

But you bring up a good point, we call the class 18HT, as in 18 feet and then all the rules measurements are metric.

Bill