The Royal Yachting Association covers all aspects of sea and inland sailing life, not just yachts and dinghies.
It sets down the rules by which all clubs operate including handicap calculations, race starting procedures and other general rules and regulations.
Without them, there would be no rules and clubs would do different things which would inevitably cause the inter-club sport to collapse.
They also set safety standards and requirements for clubs and so association with them is necessary as an Insurance condition.
They run training courses, everything from how to handle a simple dinghy to ocean navigation and more!
There are may aspects they cover, from personal for-sale adverts to legal advice and many, many other topics.
Take a look!