ORC Club v. ORC International
ORC Club - certificates do not require verified measurements. Instead, owners are allowed to declare select measurements while the rating office assigns other parameters. Where input data is lacking, the rating office will apply estimates or default values that err to a faster rating.
ORCi - based on a complete boat measurement carried out by a US Sailing Official Yacht Measurer as defined by the Universal Measurement System. The hull and appendages must be measured and the offset file must be approved by the ORC to meet ORCi standards.
Some races have a GPH 560 Rule. This states that all boats that have an ORC GPH of 560 or lower must have a valid ORCi certificate to race. Please check your race's NOR to determine which level of certificate is needed for your boat.