What is your pole length ?

What is the overall area of your spi/hooter ?

What is your spi hound height (gate height) on your mast ?

What is your mid-girth measurement ?


That are the only 4 limits that are set on the use of any headsail. Be it either a spi, a gennaker, a hooter, or an (as you wrote) hour glass shaped headsail.


With regard to the Hobie Wave I need to know the specs that are ruled upon in the F16 class rules. Things like mastheight, width, length, weight, combined sailarea, luff lengths, etc.

If the Wave fails on any of these accounts than it is not Full F16 Compliant HOWEVER you can appeal to sections 5 and 6 of the class rules that allow the grandfathering of your Wave:

This is defined as :



7.26 Grandfathering

The allowing of non Formula 16 compliant designs to race against fully compliant Formula 16 designs


In summary it comes down to showing that your boat has a rating equal or slower than F16's (and implicitly F18's as well) under BOTH the ISAF and TEXEL handicap systems and requesting a dispensation for your non complaince with the local F16 class head. That is when officially accepting to race "First-in-wins" with any and all other F16 and dispensated F16 designs.

Up till now we haven't refuse anyone. And I suspect that the Wave may just be on the right side of the ISAF/TEXEL rating threshold even with a non-compliant F16 headsail.


Wouter