The way i see it
The I-17 sold mainly in Eu called the Nacra 17
In North America the I-17R is the main model sold now called the Nacra F17.
both are single-handed classes.
The Nacra F17 will have two spinnakers, a larger one for sailors over 210 lbs. with a estimated sail area of 12sf larger than the standard one. (nice idea)
no mention of any formula class that, I have read, but I might be missing something.
F16 Class, is it a single handed class or double handed class seems odd to try to be both?
one final note, HEY Wouter its Nacra not nacra, I see you cap all other manufactures.
just my .02
Ted Z