Varies
As Jimq26 said, it varies from region to region, and it also varies baseed on equipment like roller furling, fixed or folding prop, etc. I didn't see a 240 on our list (Detroit area), or on this one (Long Island Sound?): http://www.pipeline.com/~wayneb/phrflis.htm but there are some links to other regions on that page. If you're serious about racing, I'd call a local yacht club to find out who the rating authority is on your lake.Kevin