2017 – 2020 Rules
Here are three documents on the rules, copied from the ISAF ( now World Sailing ) site, which provide all the information that you really need. There is a lot of ‘stuff’ here, so the most important, most relevant part, is Part 2, Rules 10 to 20, and Annex E which deals specifically with radio yacht racing.
Racing Rules – 2017-2020 – Click Here
Racing Rules 2017-2020 – Study Version – Click Here
Racing Rules – Changes for 2017-2020 – Click Here