RE: GO or Carve? From 129 to 170?
Ian has asked me to provide some advice on your "ultimate board" questions.
I agree with Ian, there is no simple "get this board and it will do all that you want" answer.
First lets put "windspeed" (which is basically what windsurfers use to gauge their "fun factor") into some different numbering systems besides your preferred Beaufort Force System.
Here's a little chart:
Bft Knots Km/h m/s mph description
1 1-3 1.1-5.4 0.3-1.5 0.7-3.5 Light Air
2 4-6 5.5-11.9 1.6-3.3 3.6-7.5 Light Breeze
3 7-10 12.0-19.4 3.4-5.4 7.6-12.2 Gentle Breeze
4 11-15 19.5-28.4 5.5-7.9 12.3-17.8 Moderate Breeze
5 16-21 28.5-38.5 8.0-10.7 17.9-24.0 Fresh Breeze
6 22-27 38.6-49.7 10.8-13.8 24.1-31.0 Strong Breeze
7 28-33 49.8-61.5 13.9-17.1 31.1-38.3 Near Gale
OK, you are asking for a board that will be fun in F2 Bft. That's only a max. of 6 knots. Perhaps the new Apollo, with a very large sail, could be fun in F2 Bft, but I think this is mostly the realm of the Serenity and Phantom in sub planing mode.
As Ian suggests, even the top pro FW sailors don't plane, with 12.5 m2 rigs in much less than Bft F 3.
The Go board you want, isn't going to do much or be much fun in Bft F2-F3.
When the windspeed gets to Bft F4 now you are getting into the "fun zone" for the GO boards. As Ian suggests, you will need an 8.5 m2 rig (or larger) to have much fun in 9- 11 knots (Bft F3/4) but the boards will begin to plane up at around that windspeed.
You will have some real "technique" and "positioning on the board" issues to resolve (coming from your old poly longboard) but you can easily make those transitions with a little advice for the forums here.
Probably the Windsurfing School forum has the most information on this.
The smaller GO boards, (139/129) are really too small to give good performance for a guy your size in < Bft F5.
So let's focus on the "mid size" GO boards (the 155 and 170).
The larger the GO you choose, the more light wind potential you will get, but at the cost of less high wind potential and comfort at your skill level.
I think the best overall blend, for what you seem to be asking for is the GO 170. Start with a 6.5 rig, and then once you've gotten accustomed to the wider shape, and no centerboard/daggerboard, purchase a larger sail or 2 to get the full range from around 9-10 knots to perhaps 20-22 knots.
That's pretty much going to have you planing right at the high F3-low F4
wind speeds (9-11 knots) with an 8.5 m2 or larger rig.
But, this will mean you will be "slogging" and not having much fun in lower Bft F3 and F2.
For that you would need the Phantom I think. But the Phantom is not going to be so good (it's a big wide and long board) when the windspeed reaches Bft F5.
If you can only have one board, my suggestion would be to try to find an '06 Starboard Hybrid Carve. It's smaller than the Phantom, and also "transitions" to being like a large Carve board by simply swinging up the centerboard. It's good to probably 18 knots, maybe a little more.
That's the closest I can come to a "one board" solution for you.
If you looked a getting 2 boards, then a Phantom and a GO 155 or 139 could be a good combination or perhaps the Carve 145/133 with the Phantom.
Hope this helps,