Thanks fellas for this thread and particularly the narchies amongst you. I've had some thoughts on this for some years and having participated in that field (and bellyboarding for 40 some years) I'm back into design and build of same. FWIW I'lll be using thicker fins that utilise both root chord and tapered symmetric (non aerofoil) fins. Specs are solid western red cedar (glassed) 52" x 22" x 1" but with a hydro step pintail.
Pics in time.
Always like thick fins...easier to foil without any flats and they are quicker.........Ive always considered that the standard 10mm thickness come about because its the minimal amount of material you can use to make mass-marketed fin systems and maximise profits.......kinda like when an accountant does your R & D....
Bumped, as a courtesy to interested readers.
Good work Bill… Re-re-rereading just the first page is a full on lesson from real experts…
As Greg L. said…
************** SWAYLOCKS RULES*****************
Now if I can just figure out how to measure how far those fins should go from the rail… Ha!
And, Mark S. you were a nice clear voice of reason and insight… You’re missed here Mang… ;-) Love and Peace - to be sure…
…hello,
yes, a big % is for that; but the younger surfers demand lighter boards and they did not born when the fins were thicker.
You would say that some weight in the tail is good for some surfing, model, etc but the guys only feel the lightness or not of the boards
Young surfers are all about tricks or pumping action to hit the lip and try aerials with the lightest PU board they can get.
The other day I checked several new FCS lighter fins, and they are really light and stiff.
-for the road you say about maximise profits, etc is the problem that you don t see marketed thicker fins done with foam and other materials; in that way you can obtain lighter, thicker fins…too much money…think sanded clear not glassed on fins boards
From what I can tell the fcs GAM fin and the fcs Sunny fin are the same template and only differ by thickness or foil thickness with the Sunny fin being thinner.
I realize thinner foils are for bigger, faster waves, any comments?
anyone?
[quote="$1"]
I realize thinner foils are for bigger, faster waves, any comments?
anyone?
[/quote] Otis , I have a simplified rule for fin size , ie the more the increase in velocity , the more efficient the fin works and the less fin area needed. When the waves get bigger or faster , I put smaller fins on the board....seems to work for me......I've always thought the standard production thickness for centre boxes should be 1 1/2 times thicker , to get a better foil........
[quote="$1"]
I realize thinner foils are for bigger, faster waves, any comments?
[/quote]
The fastest guns I've ridden in really big waves, (15 ft Laniakea, 20 ft Sunset, 25 ft Waimea) had one inch thick fins 6 inches deep, with a 10 inch base. Many things about design elements of surfboards, for optimum performance, are counter intuitive. Power, drive, and speed, were easily on tap, at will.
Another classic Swaylocks fin discussion that deserves to be bumped again.
Wow, I was just reading this thread yesterday, and lammed up some existing fins with some plywood this morning. I’ll foil them out and add a layer of glass. I’m really interested to see with my level of surfing if I can tell the difference. Also curious to see if it effects paddling.
Here is a short testimonial on two fins I loaned a surfer since I wasn’t using them. Both are thick foiled fins.
The orange fin with the dongle in the rear was a “one-off” request and came back to me not being ridden (I believe cause it was not “flexy” enough). I cut off the dongle and sent it on to another surfer.
Testimonial:
The ebony Thraikill template works surprisingly well in my 7’6" vaquero. It stiffens the board up for bigger surf , holds like crazy when it gets steep allowing for G-force rail turns. It also feels faster and more stable than a flex fin down the line. I still like a flex in it for less than overhead surf but after that the thick ebony fin shines.
The orange chambered fin has found a home in my 9’3" Vaquero. I literally haven’t taken the fin out of that board since I first tried it months ago. It works so well.
Very similar to the ebony fin in the speed and hold, and the template and stiffer feel allows for quicker direction changes than with Marc’s A flex. I use the this board allot in big winter swells because it’s like a mini glider. best paddling board I’ve owned and handles large thick gnarly nor-cal conditions like butter!
End Testimonial
Thick fins are awesome performing fins. Thick fins suck when it comes to manufacturing them. Basically cut out 3 fins (for 7/8’’ thick fin), hollow out one and laminate the other two on to the hollow fin. Now foil for hours. For 5/8’’ fin all that is needed is two fins and a couple hours of sanding.
Dave
To make thicker fins, I prefer starting with a center section of glass 10 layers or so, then add softer material like foam or wood on each side to get close to the thickness I want. The sides don’t go down to the bottom for box fins, just to where they would meet the board. Shape the foil then add more glass on the outside of that, re-foil (clean up), then get the base thickness right. I find it so much easier to get a nice foil with the softer material. The center glass section helps give the fin a solid middle for the glass on the sides to attach to and it serves as the bead. Similar to the fin on the bottom.
Nice thing about foiling all glass is the layers will help guide you, but I think it’s a waste of glass, resin, and time.
Dave is the bottom fin Bill’s template? How did the top fin work with that part in the back?
Do you think the fins work well mainly due to their thickness, or due to their stiffness? I’m sure with the lamination process of the thick fins, they are extremely stiff.
Both.
Harry, the orange fin I believe it was never surfed with that thing in the back. Yes, it is Bill’s template. The fins I have made with that template have made all it’s surfers stoked.
Dave
Phebus,
Foiling a fat fin we are able to add characteristics that skinny fins don’t allow due to lack of fiberglass. Having a blunt leading edge, thickest part of the fin pushed further back and a 12.5% thickness to chord ratio is what I’ve been using. Please know that I did not come up with this method on my own. I have had multiple conversations with Bill (and reading Sway) and aside from adding flex to fins…everything is his preaching.
To take Bill’s answer one step further…I worked closely with a guy who surf’s big gliders at Lowers all the time and once a year tours down to Scorps. He has changed up the shaper of his boards but a couple things have remained the same. That being the size/size range of his boards and his 9.25’’ Skip Frye flex fin. I made several 5/8’’ thick fins for him of that template with similar flex to the skinny version and everyone of the fins were reported to be better performing than the skinny version. Further down the road he asked to try the 9.5" GG 4c and that ended up being stiffer than the Frye template fins. Last I was told was that this was the best fin I sent him.
Dave
Picture of the surfer, Frye template and thickness. Using the Kumano System bearings which are also reported to work well.
I know the surfer, and he loves the fins you’ve made him. He is a big guy that surfs well, and really pushes his equipment. His comments on your fins is one of the reasons I’m going to experiment. Flex aside, aren’t the Frye template and the Greenough 4C very similar? Thanks!
phebus,
Yes, templates are similar.
On a side note…when looking at templates and keeping the 12.5% chord to thickness ratio the narrow base High Aspect Ratio fins (think Frye and 4c template) are the two outlines that don’t push the thickness into the 1" realm.
The fins we see in surf shops, if they’re for thrusters or quads are most often molded, however some are foiled from fiberglass/polyester laminar panels; if they’re center fins in excess of six inches 95% are foiled solid poly/glass laminations. There are some large center fins that
are molded as well but they form a small minority of the big picture.
One doesn’t see epoxy used as the glue in laminated fins.
Epoxy laminations of a given thickness yield panels 15% lighter than when done as a polyester lamination.
Each one has a very different flex modulus as well (Too damn soft IMHO, thus spilling off the drive leverage a surfer requires for performance). However, when carbon fiber is layered into the picture we have a new ball game. The flex modulus takes on a brand new pattern along with the lighter specific gravity. The same light lightness and variance on flex modulus will result when various types of
thin wood sheets designed for veneer work are introduced in the a panel.
If one wants a very light fat fin it can be done with a center spine of several laminated layers with foam applied to either side of it.
This can be foiled as desired and a laminated shell placed over it. If done as an epoxy/fiberglass/EPS composite the result will be very, very lIght but composite construction leaves one with a very rigid result for obvious physical reasons. Thick fins done this way can yield very nice performance when glassed on a long board. For box fins the technique works well as long as the fin base is beefed up in the lower 10 to 15% of the fin height. I believe that the increased fin thickness results in a soft feel through the turns and greater hold of the trim line.
I don’t think we can contest the thinner fins will mover through fluids with less resistance and thus will go faster as they create less turbulence. Thickness is of course relative and in the end on a given template of a given height of a given thickness the makes and breaks
are the subtleties along the complex curves on the foil.
I know Tom has given extensive research to recipes in producing molded fins that perform well. If one want to produce in quantity
there is no doubt the most effective method. It’s not for me. I neither have the money to invest in it nor interest. I’ll continue to experiment
with fins that incorporate some sort of lamination and study to disappearing wake-path of performance.
Stay Stoked, Rich
