Fin size - effects on surfing

[aurfalien]

Hi,

So I've been tossing around the idea of getting smaller fins as I only weigh 145-150LBS.

FCS sometimes has small and grom sizes for a particular fin template.

If I look at the Nexus H3 for example in the S/M/L sizes, the characteristics are all the same regarding drive, pivot, etc...

So what effects does size have for the same template?

[Slowman]

Well if you have fins that are too big they will stiffen things up. If they are too small you end up losing drive, and possibly sliding around. Sometimes slide can be good if it can be controlled and is predictable, like you want hold through your bottom turn but some slide on a cut back can be fun.

[iggy]

Hi,

So I've been tossing around the idea of getting smaller fins as I only weigh 145-150LBS.

FCS sometimes has small and grom sizes for a particular fin template.

If I look at the Nexus H3 for example in the S/M/L sizes, the characteristics are all the same regarding drive, pivot, etc...

So what effects does size have for the same template?

Small fins, something with a bit of rake to compensate.The nexus are gonna be a bit loose, as a quad they will go great. For thruster check the PC3

[aurfalien]

You're talkin hold but there are 2 more characteristics, drive and pivot.

The size or depth as FCS puts it on there site, adds to hold which is what I assume most think of when they say stiff/loose.

But what about drive and pivot?

So, if 3 fins have the same drive, pivot and hold ratings such as the H3 in S/M/L sizes, then what would be the real diff in getting the S,M or L?

They rate it by weight but this is a confusing rating as once we are on a wave with some speed, don't we all plane on top of the water about the same?

BTW, does any one wanna trade a set of unused H3 Medium tri set with a small?

[prjwebb]

In a straight line your just going to get a little more drag off of bigger fins no matter your weight but once you start turning and pushing against the fin it's going to depend a lot on weight. In steep, powerful waves I don't think you need as much fin as you would in smaller, weaker waves where you need to generate speed. I'd probably use a smaller but more raked set in powerful, perfect waves as the wave in generating speed for you.

If you're too heavy for a small set of fins when you push hard against them they'll slip and release when you don't necessarily want them too and you'll be losing drive because they won't have the area to handle the forces you're putting against them. If you're using too big a fin it's going to feel stiff and slow through turns but could well fly straight down the line.

The drive, pivot and hold ratings on the FCS site are dependent on you using the correct size for your weight. If you used a large set when you should be on small you'd probably find lots of drive and hold but little pivot and they'd probably feel sticky on subtle movements and direction changes.

I'm no fin expert but that's what I think anyway. Bigger fronts with a small rear are a good remedy for that extra drive but still a looser tail.

Also it comes down to the template and the materials as much as the size of the fin. A smaller, very stiff fin with a more efficient template and foil is going to offer more drive and better release than a large, soft flexing fin with a big sweeping template. It's worth hunting for someone like Greg Griffin's comments on fin design. If you can sift through his vague answers and random remarks you can find some real gold.

[aurfalien]

Many thanks man. I understand now.

I'm at the very low end of all my fins which causes me to put effort into my turns, that is until I get better.

So, all in all not a disadvantage as I need speed in order to get to the point were a maneuver is in order.

[prjwebb]

Yeah you need speed to do anything.

In your thrusters try a smaller fin at the back and it'll free the tail up. Also try pushing the rear fin right to the front of the fusion plugs, that'll free things up too.

[Chris]

good debate here!! lots of good stuff already!!

my only 2 cents is that its important to remember that you only want to increase in size in a manner that reflects your weight and the size of your board and that there CAN be too much of a good thing. Meaning don't just jack up the area of your fin if you want speed, address it by paying attention to sweep, how the area is distributed across the template of the fin and also by paying attention the foiled vs flat fins...

Cheers!

[prjwebb]

Good point, inside foils are a whole new thing altogether!