Curiosity on standard fin sizing in new boards.

[theq]

Greetings all.

Recently I bought a 2019 104L Goya quad wave. I have now ridden it twice in less than optimal conditions. I'd have to say that of the three sessions only one was particularly fun. The other two had me sailing in gusty conditions with a less than favorable wind direction. The board did feel pretty nice on waves.

Not too sure about the speed in getting up on a plane though. It seems to be a bit sluggish getting there. And I can't seem to get it to point as well as I thought I would with the four fins. Of course that may be tied in with taking a bit more time and effort to get it planing. I don't expect it to plane up like a single, but a little sooner would be nice.

So I started looking at the fins. I found that my last new board, a 95L Simmer FSW, was was appreciably under-finned for me. Now I'm thinking that the set of QS 350 MFC fins might be giving me a similar issue. I'm considering putting in a set of larger back fins.

The 350 set that's in there has rears that measure a tad over 15cm depth. The standard side fins are ~9.2cm deep. So we're looking at 15's and 9's. Presently I have K4 side fins in that are a bit under 9cm but have noticeably more area. Since I have to two sets of sides, standard and K4, I may try just replacing the rears with a set of 16's. I know that my Simmer tri-fin improved exponentially for me when I replaced the 15cm rear with an 18cm, and decreased the sides from 13cm all the way to 10cm.

After all that lead-in, I'm really just curious about whether or not the prevailing tendency is to increase the size of fin sets from what comes standard in new boards. Or do some riders tend to decrease fin sizes from standard manufacturer supplied, or perhaps leave them as designed? My experience is that, at least in terms of the rear fins, I'm two for two with feeling they were undersized from the factory. With any luck, I'll get the same improvement in sail-ability by increasing the size of the back fins in the '19 Goya. Cheers all.


Then again, it may just be the way I sail, i.e. not super efficiently, that has me needing assistance from bigger fins.


FWIW, I weigh ~170 lbs.

[dllee]

At 170, that is a big wave board for light winds, so add your wider sidebites and get rears with more surface area.
You might be a backfoot sailor, so need more fin area.
If you only ride waves, fin sizing stock is better.
For blasting and jumping, more fin holds in better and planes up sooner by not sliding sideways.
It's a style thing. Freestylers might choose a single 16 cm fin, while bump and jump sailors use a 27 cm single fin.
Use what works for YOU.

[U2U2U2]

What size sail ?
What are the K4 sides , the 9 s that have more area than ? The 15 rears are MFC ?
Things I thunk of.
You recently got the Goya, certainly a possible contributor to slower planing.
It’s a Goya, it’s a wave board.
15 and 9, big 9s, I use this size on a quad of 96l, not smaller , but at times larger,I have a fin addiction, so I have a lot.
I would go with slightly larger rears, like 16 or 16.5 (K4 Rockets). 17 if small in area a maybe, in K4 the stiff Leon in 16 or 17.
I do like a combo G10 rear and K4 fronts, looser yet with grip drive ,all that stuff.

I could be totally wrong.YMMV.
I am downsizing my fleet I have a lot of fins that would like new homes.
PM, if you have any further questions.

[U2U2U2]

[theq]

[theq]

[U2U2U2]

The Ezzy fins will have toe in. Look at the bottom , base or bottom of the fin.
If they are 2 or 3 , that will reduce early planing, they will turn better. The have 1/2/3/
Often the case , worm can open, I feel that a 5.0 is pretty small for that board, if I was powered up on that I would be on small fins for sure, 14/9 15/ 7. I would even try all 12 or 13s, all the same or near to same size.

[theq]

For our conditions around here guys have been going to larger boards with smaller sails. That's why I bought the 104 as a lighter wind wave board that I could use a smaller sail on. Yesterday I could have used a 5.6M or so, but I might have been killed in the gusts. I got launched once when I had the 5.0 up. 2 minutes later it took me 10 minutes of drifting before I could waterstart.

My later, and longer, go-out was using the 5.3M Banzai. My best session on this board was in conditions where the wind was nice and consistent and I had the 5.0M up.

Oh, and I took out one of the Ezzy K4's. I must have had some parallax error when I measured the fin earlier. Doh! Once I saw a "10" molded into the fin I took another measure. Yup, it's a 10cm. It looks like there's a 1 degree mark on it, so I guess it's the "1".

You can see how much more area the K4's have than the standard sides with the 350 set.

[U2U2U2]

The 350 is the total area of all fins, I think. Which is useless to me.
How long is the MFC side fin ? This is not a G10 fin it’s resin .The Ezzy fin is a Stubby profile, the 1 degree toe in, is minimal, unless the board itself already has toe in.
The remark what we do here, with larger boards , where is here ? At some point the board is too large for a sail size, large also true.
It’s possible that the rears, the 15s are small in area as well. So you may need more area overall.
If I get bored I will work up what 4 K4 fins have in area compared to those MFC .
In 15/9.

[U2U2U2]

You will need to ref the K4 site for these fins but, using your 350 cm2 as total area.
These are some of the possibilities.

Scorcher 16+ Stubby 10= 392
Stubby 15 + 10 = 376
Scorcher 15 + Shark 10 = 344
Leon 15+ Shark 10 = 356
Leon 16 + Rocket 10=360
Rocket 16.5 + 10 = 376
One 17 option
Scorcher 17 + Shark or Rocket 10=396

This gives you a comparison