Hobie doesn't make that decision, although they are certainly involved in it.

The first step is to make a proposal to the IHCA Rules Committee, who would review it, solicit sailor input and make a recommendation to the IHCA Council.

The IHCA council would then vote on it.

The H-17 is also an ISAF International Class. ISAF must ultimately approve class rule changes.

Racers do not "regularly buy new sails". Most of the highly competitive H-17 sailors use their sails for 5 - 6 years.