MARY, Why not sail both!! If there are enough boats "of one design" nominated at a regatta, then those boats only have to have their positions "across the line" recorded to have had their OD class results, and if they have an appropriate "yardstick/rating" then they are positioned relative to ALL other boats sailing the same course and the same start. Or if a "back calculated" handicap system is incorporated, then similarly their individual relative positions in relation to the rest of the fleet is also known. Not only do they know how they perform against the sailors within their own "class", but they can also see how they are stacking up against the best sailors in other classes as well, which always helps to truly assess just how well they are REALLY sailing. The argument that to have "other classes" on the course at the same time "hinders" the "one design" classes sailing is a bit of a "furfee" as ALL obstacles on the water average out the same for all competitors over the duration of a race, and beside which any obstacle on the course should be treated as a test of the individuals sailing skills as to how he/she handles it.