Personally I think that a given build adheres to a specific class that it should adhere to that class rating. Ergo a Taipan 4.9 with spi must sail of the F16 rating, the BIM A-cat El-Cheapo races off the A-cat rating and any F18 foundation boat races of the current F18 rating.

Otherwise any of these boats should form their own SEPERATE class under a different namen and acquire their own seperate rating.

Wouter