How Standard are Standard Fins?

[BlueSki]

I pulled the fin from my my son’s Vapor to put in the Denali fin. He has a 2017 Vapor. When I put the fin next to the fin from my 2018 Vapor I noticed the holes where noticeably different in their placement on the fin. I laid the fins one on top of the other in the pics that follow. Is this common across stock fins and does it really matter?

 

 

 

 

 

[BraceMaker]

How do they compare overlayed rear edge to rear edge (dft) and depth matched.

[Bill22]

Is the one with the round hole for the wing thicker than the other one?

[DW]

Looks like several differences between the two fins, more than just the hole position difference. It would be interesting to know the reasoning behind the changes.

[Horton]

Those differences are for all practical purposes trivial.

[BlueSki]

To answer questions, no matter how much I line them up off of the curvature or holes, there are differences. Using the front and rear contours, one fin is contoured deeper than the other.

 

@Horton, that was my expectation. The wing would be in essentially the same place and the holes are generally in the same place. Conversely, we have all learned that the sizes of the holes (angled drilling) matters quite a bit.

[Stevie Boy]

@BlueSki fit it, ski it, like it, keep it, don,t like it, dump it, simples.

[eleeski]

"Flex matters." I believe that was @Horton 's marketing for his fins. One of the few things he was right on. Materials, thickness and shape affect the stiffness. And noticeably affect feel and performance.

 

Pac man fins (a personal favorite before I started laying up my own fins) added some flex to the aluminum fins - especially if the fin was somewhat flexible to start with (yes, different aluminum alloys or treatment varies the flex in aluminum fins). Oversize holes (popular at Imperial) do the same thing. Other unconventional shapes also did the same thing.

 

Not sure about running the fin backwards but that was popular for a while. Schnitz fins? And there was a time when everyone had a Carbon Fin. People ran some incredible buoy counts on weird fins.

 

So your fins are effectively the same despite trivial differences.

 

I have a couple fins I like. They have a scribe line that gets the setup close to right settings regardless of what ski I'm trying. @Stevie Boy is on to something.

 

Eric

[DW]

What is the 'standard' material used for our aluminum fins?

[SkiJay]

@DW 6061 aluminum

[Fehlindra]

Changed the thick fin on vapor -16 to the thinner one that comes on vapor -17/18 i liked it better it changed the behavior in the turn more smoth feel fin settings was the same @skijay did an more complex explanation read it

[eleeski]

@DW I used 7075 in the aluminum fins I made. 6061 bent too easily and stayed bent. The 7075 was stiffer, resisted bending and would spring back into shape. The 7075 off the shelf felt like the stock fins I was comparing.

 

I don't know what alloy the manufacturers used, if they were heat treated or anodized for extra strength. 6061 is very common and workable. Lots of ways to do things.

 

There were some stainless steel thin fins.

 

For a while, Carbon Fins were the standard aftermarket fin.

 

@Fehlindra How did you shim your fin block for the different thickness fin? I had issues with some fin blocks and different thickness fins. Tape worked OK as did beer can aluminum for shims. I had some fun shimming with soft rubber which let the fin flex a bit but that took a special fin box. Details to consider when playing with fins.

 

Eric

 

 

[DW]

@eleeski : I was wondering if different alloys were being used. Did you do any data collection to compare flex v load?

[eleeski]

@DW Do I seem like a "data collection" person? I put my thumb against the fin and pushed.

 

I wanted a pac man fin for a really thick ski. So I made mine out of TLAR (that looks about right) material for the aluminum fin. Passed the thumb test.

 

@Horton gave me a bunch of Carbon Fins to try. I skied best on the softest ones he sent me. I did some mods to make them softer (pac man cutouts on both front and back were surprisingly good). I'm now making my own and found I could go too soft (great feel but I was just way downcourse through the wakes after being early at the buoy).

 

There are many ways to play with the fin. Denali fins, Donnatt's big hole fins, Schnitz fins, Carbon Fins, stainless fins, double wings and Leeski softies. Only @SkiJay can make sense out of it. Ski what works for you.

 

Eric

[Fehlindra]

@eleeski i dint chim the block or fin it just work flawless and i think the fin block just bends a litle more on both sides but cant tell for sure

[DW]

@eleeski : Good point, I have collected some data and have done a few of Johns fins along with a few I made. I agree, a soft fin feels good, and seems to reduce tip rise, the problem is I feel they slide / walk / or just don't keep the same angle of a stiffer one. I also went too soft on a carbon fin. I have a Pac Man fin that I like on a certain ski also.