The Offshore Special Regulations (OSR) are updated and published by World Sailing (formerly known as ISAF) every two years. The current edition was published in late 2019 and is the 2020-2021 edition.
The OSR categorises racing into 7 geographical area and provides rules on equipment, yachts design, equipment, preparation and training appropriate for each area. The areas are listed below and we have included some example i(n brackets) of well know races in each category
Category 0 – Trans-oceanic races, including races which pass through areas in which air or sea temperatures are likely to be less than 5°C (41°F) other than temporarily, where boats must be completely self-sufficient for very extended periods of time, capable of withstanding heavy storms and prepared to meet serious emergencies without the expectation of outside assistance. (Volvo Ocean Race, Vendee Globe)
Category 1 – Races of long distance and well offshore, where boats must be completely self-sufficient for extended periods of time, capable of withstanding heavy storms and prepared to meet serious emergencies without the expectation of outside assistance. (RORC Trans Atlantic Race, ARC Trans Atlantic Race, RORC Round Britain & Ireland Race, Sydney Hobart Race).
Category 2 – Races of extended duration along or not far removed from shorelines or in large unprotected bays or lakes, where a high degree of self-sufficiency is required of the boat. (RORC Fastnet Race, RORC Middle Sea Race).
Category 3 – Races across open water, most of which is relatively protected or close to shorelines. (RORC Caribbean 600 Race, RORC Cherbourg Race).
Category 4 – Short races, close to shore in relatively warm or protected waters normally held in daylight. (Round the Island Race).
Inshore Racing – Short races, close to shore in relatively warm and protected waters where adequate shelter and/or effective rescue is available all along the course, held in daylight only. (Club Racing in Southampton Water).
Inshore Dinghy Racing – Short races in boats that may not be self-sufficient, with rescue boats available all along the course, held in daylight only
The ISAF / World Sailing Offshore Safety Course is intended for crews in Category 0, 1 and 2 races (and certain crews in category 3 races). The course refers frequently to these regulations.
The 2020-2021 edition can be viewed at OSR 2020 2021.