Which fin length for Patrik Hybrid 91 Airinside?

    Hello!

    I recently bought a Patrik Hybrid 91 Airinside and I want to use it with a fin for light wind slalom/formula cruising. Anyone here who has this board and knows which fin sizes work well under it? I thought about rebasing some old formula fins to use under the board.

    I had this board and for Fin-Windsurfing I used an 48 cm Chopper - mit Avanti Machine sail (I think 8,4).

    It was a very good combination - but against the Phantom Foil-Set which I bought for the Hybrid 91, too, the fin-combination lost completely.

    Thanks for the reaction! I can believe the foil setup was earlier to get going than the 48 cm fin with 8.4m sail. I plan to use 9 and 10m sails with this board. 48 cm seems small for a 91 wide board...but I never used a 8.4m sail on such wide board. I will try my Carpenter 47 cm fin with 9m sail.

    The Chopper is a perfect powerfull fin - sail was 8,4 Avanti Machine, than Phantom Iris sails.

    From my personal experience: it's not worth. The combination with the fin on the water is in all point inferior to the combination with a freerace foil.

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    Hi t36,

    I understand your reply about the advantage of the foil but I tried foiling and to me it's something entirely different. The feeling is entirely different and I like windsurfing on the fin much more. Even if I need bigger sail sizes to get going.

    I have a Patrik Formula 180 Airinside too and use it with 11 and 12m sails. In those conditions I don't even see a lot of foilers because they can't fly unless they use big sails like 9 or 9.5m. On our homespot we see a lot of windfoilers but in really light wind the wing foilers are the first to fly it seems.

    There is a simple rule of thumb that says the right fin size for a board is the width at OFO x 0,75. In this case the OFO is 77 cm so the right fin size would be around about 58 cm. This is for a sail size that is ideal for the board and that is dividing the board width in cm by 10 and than you get the ideal sail size in square meters. You can add or subtract 1m surface so sails of 8 to 10 square meters would be ideal following these rules of thumb.

    This is only a startPoint because you just have to try fins, sails and setup like footstrap positions and see what works well. That's a really fun proces too!

    To find the "best" fin for the hybrid 91 PD AI - I discussed the fin type and length with Patrik Diethelm and Ludo Jossin.

    Compared with my AI Foil 190 - the hybrid 91 is one size smaller (volume and thickness) - it's not comparible at all.

    Even with the Chopper 48 cm the speed feeling was significantlyinferior to a large dedicated full-SL-finboard. It's a compromise between Foil and Fin.

    And therefore, these boards died without successor.

    That's good to know. I won't set my expectations too high then.

    But still I'm convinced a 48 cm fin is too small for this board. A wider OFO asks for more lift and That's why this rule of thumb of fin size = OFO x 0,75 works well with as good as all single fin boards. So I will try it and I will let you know.

    I asked Patrik Diethelm which fin type I would need for my Formula 180 Airinside and he said he didn't know because the board was mainly used for foiling. So I tried the fins I had and bought some others until the feeling was right (and the GPS speeds were ok).

    I had a first running on this board yesterday. I started the session on my Patrik slalom 140 Airinside with 8.4m Duotone Warp. When the wind dropped a little I just put the 8.4m on the Hybrid 91 with a 64 cm Kashy sXs formula fin.

    I thought the fin might be too long but I didn't have any other fin In the range of about 58 cm which should work according to the rule of thumb of OFO x 0.75 so I just tried it.

    The combination was pretty ok. Maybe the fin is a little too long but not so far from ideal. I did about 20 km on this setup with gusty wind. In the luls I could keep the board planing, in the hard gusts, I was afraid of the aggressive acceleration but the control was ok. I could go really fast for a board this size with only 8.4m sail

    After the session I went to pick up the formula fin that was rebased from 70 to 58 cm. So next time I will be able to try that fin. But for now I'm already happy with the performance of this board. It goes through lulls like nothing else and is fast. Pointing is really nice too.

    HI any verdict on the fin choice? I'm thinking of buying a 91hybrid or formula foil 190 for some light wind formula/ slalom cruising (yeah I miss formula).

    How do they compare?

    I'd use it for fin mode only when waves are too high for relaxed foiling.

    I had this board and for Fin-Windsurfing I used an 48 cm Chopper - mit Avanti Machine sail (I think 8,4).

    Hi Simen,

    I only had a few sessions with the Hybrid 91 and still testing different fins. Until now the Kashy 64 cm felt best but I guess it will be better with a 58 cm fin. I bought a Hurricane formula fin that I will rebase to 58 cm. I hope that will work nicely. I'll post my findings here

    AI Formula Foil is thicker, I think t36 has a comparison photo of both boards somewhere in this forum.

    And I think a Kashy is not the worst fin you can choose for those lightwind days.

    It was a huge difference between AI formula foil 190 and hybrid 91 (Phantom X Foil).

    The 190 is wunderful and far superior regarding in foiling in very low and low conditions.

    They both feel complete different - course race foiler vs. hybrid

    Hi guys!

    Today I had a good session on the Hybrid 91 Airinside and did some fin testing. It seems that t36 who told us he used a 48 cm fin was on the right track in spite of the rule of thumb that says a 58 cm would be a better fit for the Hybrid 91. Today I started with a 58 cm Boss fin. It's a formula fin type B6 72 S that I rebased to 58 cm for the Hybrid 91 Airinside. I was on my North Warp 9.6m sail from 2013 which feels really nice on this board.

    With the 58 cm fin thr tail of the board had to much lift and the mast needed to be far in front to make the set sailable. Wind picked up and it got difficult to keep control. The board never felt loose and fast in spite of the lift from the fin that was too high.

    Then I Switched to a 50 cm F4 fin. It's a 54 cm with 4 cm tip cut with good power and control.

    With this fin I could put the mast base much further to the back and after changing mast position several times I found a real good setting that makes the board getting on the plane very easily and let it run loose.

    Conclusion for now is that the 58 cm fin was really way to long/powerful and the 50 cm fin was the best until now. I'm gonna try 47 cm Carpenter and 48 cm Z-fins the next time to see whether those give enough lift.

    The board surprised me in the way that it doesn't need a long fin like a formula board while being shaped more like a formula board than a slalom board.

    OFO of my 85 wide slalom board is 57 cm.

    OFO of my formula board is 87 cm (Patrik fotmula 180 Airinside)

    OFO of the hybrid 91 Airinside is 77 cm so much closer to formula than to the slalom board but still the required fin length is much smaller.