Nacra's Inter 18 is out of production (I think). The carbon mast is no longer grandfathered in Formula 18 rules (I think). The Inter 18's carbon mast is taller than the Nacra F-18. The Inter 18's front beam is farther forward than the Nacra F-18. Should be a steal if you do not plan to race Formula 18.

Nacra F-18 is still in production and is designed to meet Formula 18 specs.