Hi Graham, I think it's fair to say that very few clubs adjust their handicaps. At Hayling Island all classes have amended numbers, essentially, from the idea that the slower boats are (generally) sailing against the tide for a longer period of time relative to the faster boats. I'm not involved in this, but my general observation is that the slower boats do better in handicap races in lighter winds and the faster boats do better in a breeze. That said, there are so many factors involved it's better to concentrate on racing those close to you and accept every dog has its day. To be fair to the RYA/PY group, they have the biggest pool of data to make handicap calculations, so I'd go with those numbers. It's a lot less contentious :-) If you have a small set of club numbers to work from you effectively end up with personal handicaps... which may also be something to consider if you sailing friends can get agreement, but it's always tricky, hence going with the published numbers in most cases.