looking for a new fin. Saw this. Wondering if anyone has any experience with this type of fin.
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Thread: high aspect ratio longboard fin
Feb 18, 2014, 01:34 PM #1
high aspect ratio longboard fin
Feb 18, 2014, 02:09 PM #2
Interesting...I remember back in the late 80's or even early 90's, can't remember his name, surfed with a sailboat type keel that was similar to the winglets. He actually had good success with the fin on a short board. It was great in the weak surf. Saw the Huntington pro with him surfing with it. Think he made it to the semis. He glided over those weak sections.
Feb 18, 2014, 02:15 PM #3
he states that his fin design is 30% less in drag compared to other similar sized fins.
I saw that and was intrigued by it too. He makes some great comparisons to F1 cars and fighter jets and the winglets came from sailing as well. The only draw back is that there is this guy talking about it and no footage of anyone surfing it.
Feb 18, 2014, 02:40 PM #5
i remeber seeing fins like that on my dad's sailboards when i was a kid & they look a LOT like the sails used in the america's cup last year, which were modeled off fighter jet wings...& very rigid, unlike sails in the past. makes me wonder if the benefits of the high aspect ratio only kick in over a certain speed...those winglets certainly aren't going to provide any additional lift at the (relatively) slow speeds surfers generally work w/. i also wonder whether he (or they) have taken into consideration the fact that there's a lot more going on as a surfboard moves diagonally through the water while riding a wave...the wave is pushing toward shore, while the surfboard (& rider, if all goes well) slides across the face of the wave. so water isn't just flowing straight over the foil of the fins, it's also coming at it from an angle & being redirected by the fin. sailboats & planes designed for high maneuverability still use low aspect ration sails & wings...airliners use long wings b/c they don't have (& are not designed) to maneuver quickly or in a tight space. same w/ short course racing sailboats...they maneuver quickly, but don't exactly haul ass.
then there's the hugely thick foil right at the leading edge of the fin. look at your surfboard fins...the thickest part of the foil isn't right at the leading edge, it's back a millimeter or so (w/ fcs, look around the front tab, it'll be right about there). & it's also not that thick...surfboard fins have become progressively thinner as time goes on, b/c we've found that thinner fins are more efficient & thicker fins tend to be slower & less responsive. bigger fins, of course, have to be thicker to accommodate the necessary foil, but that's a different discussion.
i have an interesting (& long!) article about fins saved on my hard drive if anyone is interested. it's primarily about fin flex, but i can post it if asked.
Very interesting as he does draw this shape from other applications and seems to have done quite a bit of research. It will be interest to follow how these things translate to surfboard performance. The only concern I have is how deep that channel is cut near the base (the one that aids the water flow near the board/fin attach point). If it makes it to thin at that point, it may become a a point where the fin might shear if it hits something (say shallow bottom kick out). However, I'd rather snap the fin than bust the fin box (which happened to a buddy of mine). Thanks for sharing.. something new to think about.
Feb 18, 2014, 03:05 PM #7
I never really understood hydrodynamics of fins beyond the basic principles, I'm not afraid to admit that, but I think there is a mix of real science and pseudo science surrounding surfboard fins, which makes it difficult to believe manufacturers, shops, friends, etc...
NJSurfer42, post that article!
Feb 18, 2014, 03:25 PM #8
i'll post the article in a new thread, just to avoid confusion & derailment of this one.
Feb 18, 2014, 03:30 PM #9Senior Member
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Feb 18, 2014, 03:35 PM #10