A couple of fin questions

I've got a couple of questions about fins for use with my 98 Ltr Gecko.
I've had this board for a while and have mainly used it with an old 32cm G10 Torquay fin when using a 5.7 sail which works well. Happy with the performance with that combo.
The board came with a 34cm fin from the factory.
I would also like to use this board with my 6.7 NP V8 in less wind. Last outing on this board I went out with the 6.7 and the stock 34 fin. I was disappointed that I wasn't powered up as much as I thought I should have been with that combo. So, I bought a 34cm Tribal freeride fin with a view to solving this problem. I haven't had a chance yet to use the Tribal with the 6.7 but I was keen to hear views on the following: -

1. Will I notice a difference between the stock fin and the Tribal?
2. Is the 34 Tribal big enough to use on this board with the 6.7 or should I have gone bigger?

FYI, I'm about 75kgs.

Cheers for any helpful advice.

Nice board ,on my 100 litre board I used a 36 drake with my 7,0 ,found it a little too big as a carbon it gave me too much lift
so i use a tectonic 35 now which is perfect for 6,3 & 7.0 .bare in mind I am 93 kgs ,so i think your sizing is pretty good .at 34 .I agree with kato the tribal fin is a great up grade .I'm thinking the only way to know is by riding it .I tried a 40 on mine one day ,was good up wind ,but couldn't get it down happy sailing .

Howdy partner!

I have a 105L with 63cm overall width like yours but... probably much less tail width.
The board is great in the waves but poor as a fast freeride unless control is a priority.

Anyway, tried 36cm with 7.0 and it wasn't working. Problem is the board lacked volume and width out back to fully leverage the sail regardless of fin length. So it felt slow and draggy, hard to stay upwind. Only worked when fully powered.

In your case, while the board's volume is slightly less than mine, the board is meant to take on more sail as rails stay wide as they reach the back straps.

A strong 34 should work well. Stiffer thicker fins provide more drive and solid input while slimmer fins feel more rubbery with less low end. A stiff fin may spin out quicker than a flex fin though. So in your case going to a "better quality" fin should improve performance and work better with a 7.0. In less powered conditions 36 may give you a bit more boost to stay on a plane when it gets light.

OW, is that a powermax fin?
ion my old 90x59 AB+ I used Tribal WeedSpeed 29 all day long 5.5-7.0. I think that the 34 will be great so try & report back. It's easy enough to go bigger or smaller build your tribal fin collection. if you can find a power box carbon fin give it a whirl. Dave

I only have a one cent worth . Depends on the board rails and type of fin . I use sharp rails and get away with smaller fins .Generally what I have noticed is a pointy fin grips and works better than a sweeping fin by at least 2 cm or more . They give more lift when going fast . I wouldn't say carbon is better than G10 . Is a Ferrari better than a Nissan GTR ? I've had both good and average . I'd say pointers are better in every way except turning especially in rough water . Because I'm only in flattish water nowadays , I only use pointer fins . On a sharp railed board 40 cm pointer sounds about right for 6.7 and 7.7 V8s . I use those sails but I'm heavier and like big fins for lift .

That's a funky looking fin . It kinda looks pointy but is swept back .
I really can't comment .
Saying that , it is the upper class model and JP make some good expensive G10 fins.
Generally boards come with fins on the large size , nobody wants a spinny outy board .

Too many variables to answer . You just have to try . For example , on my biggest board with a 9.4 V8 I use a 55 , 50 and 45 cm fin . 55 if it's borderline planing , 50 when comfortably powered and 45 when the water is flat and I'm trying to go fast ,a 28 cm Fangy when it's shallow .
As a side note , the Fangy 28 has more anti spin out qualities than my 55 cm pointer but doesn't produce the lift.

There are more to fins that just the length ... the thickness and chord make significant differences ..

I broke my 32cm slalom fin, bought a trendy racing fin in the same 32cm length as a replacement ... felt like it had about the half the lift of the original OEM fin .. might be great for racing pros at 40+knots, but quite different for racing with mates.

I've just gone from a 52G10 to a 44carbon fin on my big slalom board. 44 blows me away that it works with the same sail but better faster. Lockwood fins.

Gordon, powermax are a powerful fin for their length. You should be OK if properly powered up. Would be perfect in the 105 fox otherwise