The International 420 Class Rules
The 420 is an International Class which means the 420 Class Rules are owned and maintained by World Sailing, but with input from the 420 International Technical Committee
The Class Rules specify the 420 and how it is used – this is the document which details everything from how big and what shape a 420 should be, how it should be constructed and what the accompanying things, such as spars, sails, control systems should be like. Any 420 wishing to race must comply with these rules.
The current Class Rules were released in December 2021 and can be found HERE:
Summary of the key differences between the 2017 class rules and the December 2021 rules
The Equipment Rules of Sailing (ERS)
Of all the rules that relate to 420 racing the ERS are probably the least read. These are quite technical and should be read in conjunction with the Class Rules and provide more general governance of the equipment used in the sport. The ERS rules are revised and published every four years by World Sailing.
More information about these rules can be found here: https://www.sailing.org/inside-world-sailing/rules-regulations/equipment-rules-of-sailing/
They are also available in the World Sailing App which is a good way to keep these rules on your phone.
The Racing Rules of Sailing (RRS)
The Racing Rules of Sailing are owned and published by World Sailing and govern the rules used when 420’s race. It’s really important you read these! They are available online here https://www.sailing.org/inside-world-sailing/rules-regulations/racing-rules-of-sailing/ however I recommend you download the World Sailing App which allows you to keep a copy on your phone, ready in case you need them for a protest!
Reading these rules can be a bit boring(!), so I recommend you buy the following great book as it includes the Racing Rules of Sailing, but also includes pictures and some scenarios which make it a lot easier to read and understand them.
The Rules in Practice 2021-2024 by Bryan Willis