Time for a summary report.
Before I get started: Why the heck do the attached photos from my previous posts not show up any more? Does anone else have that problem? They showed just fine initially, now they have been replaced by a link that does not work.
In a nutshell:
A): What I think:
I think the polycarbonate fins made by Roy are in all likelyhood better than their fibreglass ancestors, but I cannot find a way to prove this, not even to myself.
I believe they are better because:
- the material is light and strong and has a decent amount of flex to it.
- I was able to fix a ding to the trailing edge (not sure how it happened) by dragging the fin along the edge of my car boot. On a fibreglass fin, the ding would have required sanding and would then have left a defect. On the polycarbonate fin, the trailing edge could be bent back into shape so perfectly that I cannot feel the damage any more with my fingers, although it is visible because some paint from the car appears to be permanently embedded...
Using more appropriate tools, the trailing edge of the fin could probably be repaired more easily than a fibreglass fin and it would leave next to no trace.
- The poly fins are buoyant, you can find them again if they ever come loose in the surf. I guess the reduced weight conveys a performance advantage, but that might be a wrong assumption, considering that most people seem to like the weight of polyester McCoy boards compared to the lighter Surftech's.
- The foil of the polycarbonate Gullwing and Gullwale fins is much thicker than the foil of the various fibreglass Gulwing fins I have. It is based on a particular foil (Eppler 168?). I assume this foil has some sort of evidence base regarding it's performance, but I have not researched this at all. Roy can probably explain why he thinks that the Eppler shape is better than the thinner original fin foil.
A disadvantage of Roy's fins could be that the fit is less than perfect if the fin box has been sanded off during installation. The original gullwing fins always have a rather abrupt (i.e. no) transition between box and fin, while the polycarbonate version is shaped much more like a glassed-on fin (but only fits snuggly if the fin box is unaltered).
- the shape of the printed polycarbonate fins is reproducible, and small changes could be made and then reproduced accurately every time, whereas the hand shaped original gullwing fins are a bit different every time. I don't know what degree of inconsistency can be accepted and how much (if at all) the small differences would impact on performance.
B: What I could find / feel / measure regarding performance differences so far:
I was unable to find a noticeable difference in performance between original fibreglass Gullwing fin and Roy's Gullwhale or Gullwing fins. (Gullwhale = Gullwing with BLEF)
- In my 8'0'' single fin Nugget, I did not feel a difference between original Gullwing fin and Gullwhale fin. This includes only one session when the fins were swapped while in the surf, but numerous sessions in various conditions over several months when I used either the original, or the Gullwhale fin during a session. The main limitation to this testing is that I rarely manage to pull off anything that tests the limits of the board or the fin. My surfing ability is the main limiting factor in it all. However, a 14-year old grom on a 5'8'' Franken-Zot did not feel any difference between the fins, either (The grom gave up using the Franken-plugs a long time ago and uses the Gullwing fin exclusively instead of any other combinations).
The other main limiting factor is that the crowd factor at my local breaks is bordering on ridiculous, so that whenever there is any quality to the waves, the surfer density is so high that I cannot turn where I want. Instead, I need to slalom through masses of surfers. That (in combination with my lack of skill) makes testing of the fins difficult.
If there is an advantage imparted by the Eppler foil and/or the BLEF, then I think it would most likely be felt during extreme situations, i.e. high angle of attack, high speed, critical barrels etc. Unfortunately, I'm not the one to test anything in these conditions! I can sometimes pull these maneuvers off if everything comes together just right and I'm lucky and have a good day, but I don't have the competence to do this consistently, at will, or in a crowd.
Steve Shearer had the Gullwhale fin in one of his boards for a couple of months and told me he never took it out because he liked it so much. I'm stll hoping for a report from him, he's got the skill to actually test equipment near it's limits.
Testing the Gullwing and Gullwhale fins in the pool by hand revealed no difference except what can be attributed to the weight difference.
Comparing original fibreglass Gullwing fin to floating polycarbonate fins is difficult due the difference in weight. They certainly feel different, but it feels to me like it's mainly (and maybe exclusively) due to weight difference.
Comparing a polycarbonate Gullwhale fin to a polycarbonate Gullwing fin in the pool:
There is in my experience no discernable difference. I am unable to tell if I am holding the BLEF version or the non-BLEF version in my hand, no matter how I move the fins through the water. I think I've tried to find a difference for over an hours without any success.
Moreover, the polycarbonate BLEF and Non-BLEF fins behave exactly the same when tested in the pool using their buoyancy as the driving force: When pushed flat against the pool bottom before letting go, they will follow the exact same spiral to the surface, and they take the same time to get there.
When held vertically at the bottom of the pool and then let go, they both shoot to the surface of the pool in a straight line and take the same time to get there.
Other fins tested by hand in the pool (Ben Lexcen Star fin, dolphin fins, and various others) all feel clearly different to each other. I have not actually done it, but am certain that I could learn to tell the fins apart in a blind test.
However, I have not found a way to differentiate between polycarbonate Gullwing and Gullwhale fins, not even when I know which fin I am using.
My conclusion is that the Gullwing and Gullwhale fins work very well, at least in McCoy boards, and that the difference between Roy's Gullwing and Gullwhale fins is probably insignificant for intermediate surfers. I cannot rule out that BLEF might make a difference for good surfers, or for average surfers when surfing in good, uncrowded conditions. More testing is required.....
If all my fins disappeared, and I could only buy one fin to replace them, then I would buy the polycarbonate Gullwing fin without BLEF - if I could afford it. It costs significantly more than an original McCoy Gullwing fin, but is lighter and would be just like the last one I bought.