The Nacra 20 owes the F18 3 minutes 56 sec per hour of racing under SCHRS. (Scooby... is that an official rating/)

It's a little less under Texel of 3 minutes 34 secs per hour.

Under USPN the difference drops to 3 minutes (2min 59 sec)

The rating system differences are swamped by the prevailing wind direction and pressure.

As Smyth proved over and over again... you need to have an advantage in the light air. In time on time racing... you just can't make up the time when the breeze is on.

It would be interesting to see what would happen if the N20 sailplan had been developed to the degree of the F18's. I bet they would have the same low end gears.

Likewise, if the breeze is on... the 20's really want extra beam oh... say about 10 feet to take advantage of the power....

This is a classic horses for courses game! Who knows what mother nature has in mind next.