View Full Version : gemini trifin?

vw surfer
21st November 2009, 04:15 AM
Hi, last year i bought a gemini and me and my son started surfing 'tandemstyle' We really enjoy it. It's great fun to do. we are getting better at it, tacking is no problem. Even gybing goes well, not fully planing but getting there. The problem is: we find the board to be a little slow. it lacks topspeed and upwind ability. Or we lack technique.
In another thread i read some tips to improve upwind performance by keeping 1-2 mtrs difference in sailsize front to back. I think we need sharper rails and more fin-drive. With 7 at the front and 8 at the back( hellcat/saber) the standard fin is ok, but with 8 at the front and 10 at the back (saber/rss) we start to get spinout's wich is a really awkward feeling on a tandem!?
The 70 cm depth is a problem too sometimes. After this long introduction:
Is it possible to make a trifin? and do you think this would help give more planingpower?
If yes, what would be a good position for the two extra fins?

21st November 2009, 11:12 PM
My guess would be that a tri-fin configuration would just make your Gemini slow and sluggish to jibe.
I've had very good results on the Gemini with the big Lessacher Formula Duo 40 cm weed fin.
No spin outs, pretty good upwind, solves your depth issues over the OEM 70 cm.
Here's a link:
The Formula Duo is asymmetrical and this design seems to pretty much eliminate soin out.
My experience on the Gemini also suggests you are over sheeting the rear rig (this is easy to do). Open the rear sail up a bit so you get maximum drive with minimum side push and you won't spin out, and you will be alot faster.
Remember, as fast as the Gemini is (when fully wound up with good rigs and skillful sailors) it's still not as fast as a formula board and the rig positioning is a bit forward when compared to a formula board. Add the force from the front rig and you are dealing with a very different overall balance.
Hope this helps,

vw surfer
24th November 2009, 02:02 AM
Thank you for such a quick response. I am not sure your answer will help though. maybe i'm not asking it at the right place.
When we were sailing the Gemini the other day(well, a month or so ago), windspeed was up to 20-22 knots, slalom guys were using 5.8m2. we put on 7.2 at the back and 6.2 at the front and the standard fin (NR70). I admit it was a bit of a handfull, but then the board started to fly and i don't mean jump-fly but surfing on the fin with the leeward-rail in the water. three quarter off the board out of the water. That's what we want. If we are surfing in lesser windconditions with bigger sails, i think the fin can't deliver enough lift(i'm not sure this is the right technical term) to tilt the board on the leewardrail and really lift it out of the water. it sort of glides like sailingboat. Don't get me wrong; this is great to do, but is it possible to get more fin-area?
Has anyone tried it?
Have the designers thought about it?
Shall i look for another racingboard, design my own, or is it worth trying?
That's enough for today. Again, thank you for answering. I just keep looking

25th November 2009, 12:46 AM
Hi VW Surfer,
OK, if you do not have any water depth restrictions, you could get a more powerful 70 cm fin (or even something larger like comes with the Starboard Apollo), but I suggested the big Lessacher Duo Weed becuase I know it works on the Gemini.
I've had the Gemini fully out of the water and "flying" as you suggest, but I've done it with a pair of 4.8 m2 Sailworks Huckers, A 5.6 m2 Hucker and and 6.6 m2 Hucker, and any number of 7.5-9.5 m2 Free Race and Race sails but down in the 13-15 knot range.
Are you using the center board?
I was getting about the same performance in 40% less windspeed.
Sailor weight was 150 lbs. in front 180 lbs. on the back.
You should be able to get the nose up and lee rail lowered in around 12-14 knots.
Hope this helps,

vw surfer
25th November 2009, 02:58 AM
Hi Roger,
It must be our technique than, or lack of it. The situation i was discribing was when we were pushing up-wind, downwind is no problem. I read about how to get better upwind performance in another thread. we'll have to try this first.
I did use the dagger once,:o When the wind picked up (and the speed) it snapped. My dealer replaced it for free. Now i ordered one from the phantom.
If i can get my hands on a duo weed, we will try it.
What i don't understand is: with this Apollo you mention you can sail a 12.5 m2, but on the Gemini we have for instance 6 more meters and (almost) twice the weight on one side of the board. Well, enough said. Its winter now, we'll try and get a duo weed and maybe a 75cm Apollo fin. Try it next season. let you know if it worked. Thanks for sharing you experience,