Hi Joe

The Nacra 6/0 N A version with NE spin and class spin mods. are compliant to NA F-20 specs. and under the dispensation spin rule applied to older existing class boats ,-this provides the owners of existing boats to race as a brand class group AND as a part of a larger Formula 20 class.

The 04 RULE as listed in the 04 rule post reads --
Dispensation
Older existing designs may be given dispensation per class specs. by F-20 committee in design feature trade offs.
Example = an existing heavier mast rig and standard class smaller mainsail in compensation for larger spin area, again only applied to older existing designs per class or owners request.
The current NA N-6/0 with NE spin is F-20 compliant under dispensation ,-as is the current H-20 class with NE area spin.
note ; if changed from class sails or class specs as defined per class a coresponding change to standard spin area is then required per weight category at 300 or 270 sq ft.

further explaination -
Stock boats may add the larger N E spin. chosen by many or any smaller spin along with spin mods needed to that particular boat . Example -the 6/0 uses a different length foil wire to get the spin pole set correctly -this is a spin mod ,along with pole snuffer -tangs and all related spin hardware and gear required.

Other 6/0 versions may choose or already have a modern sq top new mainsail -rigging -or other improvements of matching main jib sail area to F-20 class specs of 208 sq ft and 53 or 60 sq ft jib or = area in larger jib if desired-
With a boat weight category of 419 + the 6/0 or any similar F-20 platform would be allowed up to a 300 sq ft spin or smaller and the larger 60 sq ft jib in compensation for boat weight .
The category one boat weight of 389 must sail with a 270 sq ft spin and 53 jib with same main .at 208 .

To recap -in NA F-20 there are 3 categories

1-boat weight 389 Lbs or any equivilant 20 platform
class model specs, -max 208 main -53 jib -270 spin

Category 2 -boat weight of 419+ any 20 platform
208 main 60 jib and max. 300 sq ft spin.

Category 3 -under dispensation -boat weight of 419+
with stock main/jib w NE spin area max.

note F-18 and other formula classes usejib & spin sizes as compensation for crew weight -F-20s already being suited to larger crew use jib& spin sizes to boat weight .