Fins are never under the center of planing mass. They are ALWAYS behind the center. Fins forward is an unstable configuration. So, if you want balanced lift, you need a separate keel fin, or you need two foils - one forward and one rearward (or both rearward).
Then it gets into the tricky part. Getting the aoa of each foil appropriate. A normal surfboard changes its aoa pretty substantially with speed - quite a lot for a stationary foil to properly deal with.
Makes sense, I wasn’t talking about moving it mid-board or anything.
Another foot to play with would be well behind center still.
My reason is the added depth and (tip length so to speak) those little wings create makes it way stiffer overall than when it was in its traditional state. (at the speeds I have tested it in so far).
These last 3 days would’ve been good testing but I ended up surfing two other boards more suited for the waves.
Another idea that has been floating in my head is (similar to what you just said?):
Imagine your stance on said board. The perfect sweetspot stance when doing a bottom turn that is maxing the board. What if you had a fin/plane for lift under your front foot, and a stabilizing trailer of sorts right under your rear. God knows what forms each would take, and the millions of factors affecting each, but it would be like the two points your weight is distributed through would affect lifting the whole board for increased speed, and backfoot control through the tail.
Just one of those thoughts that keeps swimming around right before I doze off.
This stuff is interesting but too complex to seriously undertake for my tastes right now. Sh!t I still have to get going with shaping my own foam and getting basic laminating down!
then again hmmm: http://www.springhoustonltd.com/mat.htm
Gadget,
I distribute the fins for Cheyen Here in the states or you can get them directly from Cheyne (prepare to wait and pay more because of shipping) my site is solosurfer.com and it’s in the marketplace. I usually have a min. of 50 of them in stock.
I also sell the Mccoy gullwings, You can contact both Cheyne and Mccoy through my site. I ride star fins on most of my singlefin longboards, but don’t care for them on boards with a lot of tail rocker. That curved one looks interesting, but the wings have a different angle than the keels. I remember Ben Lexen talking about the angle making a difference.
Hi solosurfer
Not to hijack this thread…but it’s something I’m famous for on other forums…
No wonder we had our “discussion” on template curve and flowing outlines!
You sell McCoys!
I was wondering why you so staunchly defended the templates.
BTW, that first one, the blue board, is just beautiful, smooth and flowing.
I won’t comment on the clear one.
I DO like the concept!
Hey Run - Thanks for sharing the ride. One of the more thought provoking threads in a while. A nice change of pace here. I learned a lot. Thanks
run, fin stall is always possible. The issue is what happens when a fin stalls.
If the fin is far enough back, the board straightens in a fin stall, and the rider can recover.
On a tri-fin, the rear fin stalls REGULARLY - it is so far back it is part of the normal surfboard control.
Now, on a single, move the fin forward and forward. Eventually you get to a place where a stall spins out the board. Unstable. Same with a twin fin - if those side fins are too far forward, a stall spins the board out.
Put a fin under the front foot - unstable. A foil with no side directionality yes, but a fin, no. Won’t work. Because in a stall, you are done.
I am fascinated by the possibility of using lifting foils to steer a surfboard. Terry Hendricks has a working kneeboard model that I do not think is correct yet, although he can use it with some success. I think you need dynamic angle of attack, and dynamic control of aelerons - controlled passively by direction of attack and/or weight distribution, and stable. Quite a tall order.
Keep it up Run, you remind me of me years ago. I haven’t surfed for a while, but there are leaps and bounds not yet reached with fins, and I really enjoy the pursuit. I know and you know, there’s so much more to come.
Thanks again all.
Blakestah, I understand man. You’re not talking to a brick wall my friend. I’ve felt fins give on bottom turns before. (it was due to pilot error in most instances)
This sentence from my last post "but it would be like the two points your weight is distributed through would affect lifting the whole board for increased speed {front foot with lifting fin/plane directly underneath}, and backfoot control through the tail {backfoot with inline control fin directly underneath}. "
clarification could be “since your weight is distributed to the board by two points (your feet placement); the front foot would be over the lifting plane/fin, and the backfoot would be over an inline control fin that provides stability (and what I learned from you that makes sense: recoverability after a stall).” Wildy seems to have already discovered this too.
Hey Wildy have you posted pictures of your inline setup before?
Sorry sometimes I type stream of consciousness and it doesn’t communicate clear images all the time. If you read that last post again with the above paragraph in mind it should be clear we have similar limitations in mind. Always appreciate your feedback Blakestah.
I still wish I had another 6-12 inches of finbox (in addition to existing) to try with the current fin’s state, I would love to feel it stall and feel the difficulty/impossibility of recovery; and it would also allow for future inline (read rear stabilizer trailing fin) stuff.
Too complex, keep it simple. One stainless spring steel 3/16"thick (maybe 1/8") foiled to a 1/16" tip 9.75" depth, paddle with the leading edge base at 15 " up and the trailing tip of paddle at 3" from the tail ah yeah.
run…
Also consider the idea that fin and board can be made to function in synergy, a balance of speed and control.
A surfcrafts directive contact to a wave doesnt need to be entirely dependant upon the fin(s).
Hey Run, no pics posted yet, I’m not at home. I’ve been sliding on snow and getting my head and balance around no fins, slide and edges. Snowboarding is nothing like surfing, except for the asymetrical stance, and the toe and heel control of edges is not incomparable to rail fins. But I have been doing longer faster leaned-over bottom turns than I could ever do on a wave.
Snow is no substitute for water and waves. Catch some for me.
Makes sense, I wasn’t talking about moving it mid-board or anything.
Another foot to play with would be well behind center still.
hey run, you can put another foot +/- of fin box in your board. just get another box and route out the front of the old box (carefully) and stuff some plumber’s putty in it before you glass in the new one with the trailing end cut off of course. another alternative (probably end up cleaner looking) would be to route out the old box completely get two boxes and cut the end off of each and glue them together and glass in place as usual.
Lee,
I defended the templates because they work not because everyone finds them pretty. Also I have ridden Mccoys for years (since way back in the late seventies early eighties) I just started ordering from Geoff back in 99. I know Geoff’s contributions because I have seen them from my 27 years in the water and I don’t believe anything magazines print (or very little) I will agree the wild one that you mention is ugly for many to look at but it was shaped for a 6’1’’ 240 lb surfer who does not always want to ride a longboard in small waves. I have had it out in double overhead and it holds great. I have only been selling Mccoys for a short time and proud to be able to. I have many other shaper influences, but I give Geoff the credit he is due unlike the majority of surf mags, which skip right from MR to Simon with little mention that Geoff influence them both prior to their contributions.
I also sell Joel Tudors and though he is not a shaper it could be said he has had more influence on kids today than any of the last three world surfing champs.
Thanx for the response, the answer, and the explanation.
Hope you do well with your business and your personal life…and get some great waves!
Thanks LeeDD,
Surfing is a great sport not simply because of the waves, but because of the diversity of our approach to riding them.
This last month I finally aquired a Starfin and surfed it in varied waves all the way up in the box.
Observations:
It definitely lifts the tail and holds that nose down. The feeling is reminiscent of the adjustable alum monstrosity I made, though looser. I believe it is looser because it is so upright, with lack of ‘rake’.
The physical appearance of the ‘winglets’ don’t indicate they would provide any noticable amount of lift. (aoa as we thought would be so obvious), but something must be going on with the angle of placement and subtle foiling that makes it work. The physical appearance of the winglets is more in line with my first winged piece o’ crap of alum, though we know that one lifted the nose.
It is draggy. In flatter sections it feels draggy and doesn’t glide ‘pump’ through as easy as a stage 6 or rich’s mental. You feel very slow.
It is harder to recover when on the foam. (re-entries/cutbacks to soup). A strange lifty floaty feeling is felt at times, very noticable at the top of pivotty backside snaps as well.
It holds well in the face (especially considering it is lifting the tail). The winglets act as fin material closer to the rail (?), allowing the board to hold high in the face if desired. I made the latest drop I have ever made on that board with any fin that far up on a overhead lowtide super hollow beachbreak set a while ago that still sticks in my mind. The kind where perfect positioning and paddling like a madman still only get you to the absolute brink of air-dropping in. Felt the fin at its absolute limit just starting to skitter a hair, half-way down the face.
Possibly my imagination but the fin needs to pass a threshold of speed to feel good in turns. Like most things it feels unworkable in really small (waist high and under) flatter waves, even if decently shaped.
Your observations on the Starfin sound about right.
My fin came w/o a bolt hole. Cheyne said “don’t worry about the bolt, the fin will adapt to the bottom.” Then I hear in his movie he’s said the same thing since 1983. Haven’t tried this (drilled my own hole) but it’s an interesting idea to let the fin adapt up or down slightly; controlled by the water moving under the board. Cool.