The number of spinnaker classes for the 2020 LCCS has changed from four to three in order to have a reasonable number of regularly competing boats in each class. However, having fewer classes means that boats with vastly different characteristics may be grouped together. To address this problem, “displacement / waterline ratio” is used in addition to PHRF rating to classify boats.
The “displacement / waterline ratio” shows how heavy a boat is relative to its waterline length and it’s a good indicator of performance. Although the class splits are still mostly determined by PHRF, “displacement / waterline ratio” helps to fine-tune the split between Spinnaker A and Spinnaker B classes and separates high performance vessels from racer-cruiser type boats. Grouping for Spinnaker D boats remained the same, this class became Spinnaker C.
The table below shows how classification changes for boats that raced in 2019. Number of races done in 2019 for each boat and the number of boats per class that raced in more than two LCCS races are also indicated.
Article on how the displacement/ waterline ratio is calculated and used: https://www.sailmagazine.com/boats/comparing-design-ratios