I know the OP is talking sailing cats, but I did a little study of larger power cats and their engines
, including fuel consumption
. Now the figures used are published by the manufacturers (eek!) or through real life where I could find/get them.
Essentially the formula 11.27 x LOA
- 280 gives a good approximation for the size of each engine
. You can also use displacement
(even dodgier numbers from manufacturers) and have 0.6501 x displacement
- 14.637 for each engine's size. These both give >80% correlation with the data points.
economy is all over the place though.