Fin Volume?

feralseppo

Billy Hamilton status
Feb 28, 2006
1,393
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I was listening to the Twinsman episode of the Surf Splendor podcast this morning. Among the eyebrow raising comments made (including spiral vee is a double inside single concave), Scales asked Matt Parker about fin volume and then posited that fin volume as opposed to surface area might be the most important characteristic of a surfboard. I believe he theorized that it could be even more important than surfboard volume.

What say you? Anyone measuring the volume of their fins? What is your fin volume guild factor?
 

youcantbeserious

Nep status
Oct 29, 2020
716
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Location location
Man I can't keep up with all this. My shaper doesn't write any dimension on my board but length. I think all these numbers are getting in everybody's head, and for the average surfer, we're not skilled enough to tell much of a difference. I always figure my board has way more potential under a better surfer's feet. 90% of time when I want to blame the board, I have to remind myself it's probably user error.
 

92122

Michael Peterson status
Jul 29, 2015
2,102
434
83
... Scales asked Matt Parker about fin volume and then posited that fin volume as opposed to surface area might be the most important characteristic of a surfboard. I believe he theorized that it could be even more important than surfboard volume.
That sounds ridiculous to me, but what do I know.

Would be interested to hear Greg Griffin weigh in here.
 
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flyinraptr

Michael Peterson status
Dec 18, 2008
2,490
798
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San Juan del Sur, Nicaragua
Seriously. Just surf.
I agree ... sometimes its better to just surf and not overthink ... but just for conversation since this is a discussion forum.... volume in terms of thickness at the base of a fin is an interesting thought... see it more with single fins ... the Greenough 4A for example is pretty thick ... would imagine it plays into lift but the question is at the expense of how much drag? The other thing that comes to mind with volume is overall weight. I had a pretty foiled out fish at one point ... and tried some old school fiberglass keels in it .... the keels were pretty heavy compared to other twin fin sets i had on hand .... noticed a difference in the board when trying to paddle for a wave .... felt like i had an anchor attached to the tail.
 

rowjimmytour

Kelly Slater status
Feb 7, 2009
8,645
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Rbeach
I agree ... sometimes its better to just surf and not overthink ... but just for conversation since this is a discussion forum.... volume in terms of thickness at the base of a fin is an interesting thought... see it more with single fins ... the Greenough 4A for example is pretty thick ... would imagine it plays into lift but the question is at the expense of how much drag? The other thing that comes to mind with volume is overall weight. I had a pretty foiled out fish at one point ... and tried some old school fiberglass keels in it .... the keels were pretty heavy compared to other twin fin sets i had on hand .... noticed a difference in the board when trying to paddle for a wave .... felt like i had an anchor attached to the tail.
Some boards "short and stubby" or a least for me this can help counter weight and love quad set up but I only witnessed anchor effect once on superbuzz but not paddling riding waves. Stretch sent my superbuzz with the FU controller set #3 and felt board bog and drag once up and going. Soon after tried thruster set worked better but once I got quad set of fu#2 took off like....
 
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Kento

Duke status
Jan 11, 2002
62,211
12,032
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The Bar
I agree ... sometimes its better to just surf and not overthink ... but just for conversation since this is a discussion forum.... volume in terms of thickness at the base of a fin is an interesting thought...
I know. I'm just grumpy because it's been strong NW winds for a while and I foolishly skipped that south because thought it would be destroyed but I found out later the error of my ways. :roflmao: Alas. Did a few dawn patrol runs in meantime to keep blood flowing; better than nothing. Hoping forecast for this weekend holds up - could be fun. Haven't surfed my 6'7" (glass-ons, not changing those!) since I got it repaired but looks like enough swell to drag that out again.

As far as the fins go, the larger fins (thruster) always felt like they bogged. Less volume will generally correspond to less surface area unless you're drastically changing material density or playing other games. The idea of osmium fins is intriguing but I'm guessing most fins (outside the LSD-infused ideas) are relatively similar to the point of area/volume ratio being about the same.

If you're going straight on a funboard/wavestorm, it probably doesn't matter too much though. :beer:
 

sdsrfr

Michael Peterson status
Jul 13, 2020
2,854
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San Diego
DLS went with calling it “volume” while actually it sounded like he wanted to know the 3D dimensions of a fin, not just the depth and base measurements.

knowing the foil is a big part of the equation and this does not show in the provided base nor depth (nor rake for the mfgs who report it).

I don’t think volume of the fin would properly represent foil, but I do think that’s something he was trying to decipher from it, as that will play a major role in lift and performance (maneuverability) at lower and higher speeds.