I am using the Starboard 9.5m raceboard sail with my phantom 320. It is cambered and remarkably light to handle for such a large sail, and the price was also very good for a racing sail. As a little bonus, the color matches to.
I chose the 9.5 because it is the maximum raceboard class size and I use mine for racing. Since the Phantom is designed for displacement as well as planing, It is good to have a large sail and this serves from very light wind up to what ever your skill level can handle. I can manage it up to about 15 knots and I weigh 65 kg. Remi Vila says he can manage it over 20 knts. (may be one day I will also, when I become world champion!!!)
If you intend to sail only in planing wind then I would stick with the smaller sails as recommended by Roger. I use an 8.5 cambered sail for wind from 12 to 20 knots and it can be hard work at the top end.
Last edited by tonymatta; 24th July 2009 at 01:33 AM.
Reason: extra info