A: The short answer is that the CRF GPH is greater by a constant 535 sec/mi for all CRF ratings, so they can be used in either form to score a race.  That is, a boat that is used to ‘owing’ a competitor 23 sec/mi with the CRF ratings published previously will ‘owe’ that same boat the same 23 sec/mi if their new ‘CRF GPH’ ratings are used, as the latter is simply 535 sec/mi  greater than the former for both boats. A more complete answer is that CRF ratings are actually first generated in terms of linear feet, (to reflect effective sailing length and thus speed potential), and they are converted internally to ‘GPH’ ratings in seconds/mile.  When the ‘MkII’ version of CRF was introduced in 2017, it was decided to subtract an arbitrary constant of 535 sec/mi from the calculated numbers to generate handicaps with values that are comparable to those produced by PHRF, and that are thus familiar to many sailors. This means that the CRF GPH rating for a boat is equal to her familiar ‘PHRF-like’ CRF rating plus the 535 sec/mi constant.  For example, for a boat with a CRF rating of 65, her CRF GPH=65+535=600.