Unlock Barnfield's mystery Fin angles

General Discussion
1

As an introduction, I am a garage shaper and have shaped (and sold!!) about 35 boards. As any new shaper, I tried to copy the best boards I owned. I am lucky to own 3 custom-made Bill Barnfields from the early 1990s.

6’6 x 20 x 2 3/4 , 6’9 x 19 3/4 x 2 3/4 , 7’0 x 20 x 3.

All of the boards ride fast down the line and have a loose, but positive feel. As I examined the fin angles that Barnfield used, I was surprised and confused by the numbers. All three boards had the exact measurements for fin placement. Rear fin was 3 1/4 " from the tail. Forward fins were 11 1/4 " from tail and 12" apart ( measured from trailing edge on deck). Those measurements made sense as Bill supposedly likes to place fins closer to tail than the standard 3 1/2 & 11 1/2.

The Toe-in angle was the mysterious number. Bill has a well deserved reputation as an exacting shaper and typically measures down to the 1/16 of an inch. However, when I drew a line with a long straight edge from the inside of the forward fins, the line intersects the exact tip of the board. ALL three boards, shaped years apart, of lengths from 6’6 to 7’0 use the same measurement. All the Toe-in measurements go straight to the nose. Exactly!

My mind has been bugging out on this point. How can such a seemingly simple Toe-in measurement be the most correct one? The boards are the best boards I have ever ridden, so Bill is right, but why this measurement?

I have come up with some theories. If you have others or if Bill Barnfield wants to explain, please do so.

Theory #1 - Barnfield once posted in Swaylocks that he had a board that he expermented with 12 different fin angles. (by exhaustingly glassing and cutting off the fins. Maybe a toe-in angle to the nose is the best for that size board.

Theory #2 - Barnfield needed a reproducable toe-in angle that he could communicate to his glassers. It is very easy to double-check this toe-in angle with a long straight edge. Bill maintains quality control be eliminating a potential error.

Theory #3 - In shaping hundreds and hundreds of boards, Bill prefers absolute fin angles that he ‘shapes around’. Meaning, he adjusts the template, rocker, bottom contours, etc. to modify the handling of the board, instead of changing fin angles.

I would like to add that Bill Barnfield is a legendary North Shore shaper and a upstanding individual. I hope he and his wife Wendy are doing fine.

Rob

2

What!! No takers?

What has happened to this otherwise highly opinionated group?

Go for it guys, Give it your best shot and later I will explain the purpose behind Robs observations

3

Here’s my theory:

As a board gets longer, the toe in needs to decrease, straighter toe for longer boards especially since Bill was in Hawaii.

So rather than relying on a set # that changes as the board length changes (i.e. 1/4 for under 6’10", 3/16 up to 7’8") Bill came up with a self adjusting method (to the nose) It easily could have been to a point 1" from the nose and that would have accomplished the same thing BUT with different riding characteristics (see #1 in the original post)

A method to maintain optimum toe angle as board size increases and yes it is easy to check accuracy

How’d I do Bill LOL?

BTW Thanks for the tip on saw stroke technique for cutting outlines, I tried it and it worked like a champ!

Jim N

4

consistency

5

With my very limited experience i don’t quite feel qualified to try and guess why Bill placed fins pointing directly at the nose of those three boards. Also it is only three boards and i’m sure Bill has shaped a couple more boards during his time and maybe these don’t have the same toe in angle, more research might yield more evidence of a toe in angle trend.

Personnally having made a 150cm kitesurf wave board which is basically a mini surf board (see attached photo) and tried placing the fins directly pointing at the nose of the board, I found the board to be very slow and hard to control with any sort of power. Admittedly here the boards driving power is the wind and not a wave so it may behave differently were you to try and surf it (wish i was 14 and only 5 foot tall again) but as soon as i changed the toe in angle to 1/8th" the boards performanced improoved, faster and much more controlable. Also found that smaller fins helped further, less lift induced drag allowing for a faster board.

It does seem to me to be a sensible idea though to have an easily reproduced toe in angle when producing lots of boards and i guess as i don’t know that to some degree you could alter other aspect of a surfboard to allow you to keep the same toe in on a variety of different boards.

Looking forward to hearing some other views on this one.

6

There is alot about this in the archive. This seems to be THE way to reference toe in if we go back a little. A standard board would have toe to the nose, or you could do toe in with a straight edge to x inches off the nose in either direction. Also for longer boards, the toe in would decrease, shorter would have more toe in and this seems to be the general way of setting up the fins.

I did some calculations at some time when checking this. It seems to me that the change in angle is very small. By referencing it towards the nose instead of saying 1/4" or 1/8" inch toe in (or even with angles) which is very inacurate and the angle of the toe in would depend on the length of the fin, you give it better accuracy.

For a 5" fin the a toe in of

1/8" is 1.43 degrees

1/4" is 2.86 degrees

For a 4.5" fin

1/8" is 1.59 degrees

1/4" is 3.17 degrees

For a board with fins set at 12" and 1 1/4" in from the rail and fins toed to the nose

6’ length 13" tail is 5.00 degrees

7’ length 13" tail is 4.17 degrees

8’ length 13" tail is 3.57 degrees

9’ length 13" tail is 3.13 degrees

6’ length 14" tail is 5.47 degrees

7’ length 14" tail is 4.56 degrees

8’ length 14" tail is 3.91 degrees

9’ length 14" tail is 3.42 degrees

Referencing toe in aginst the nose gives you a better chance of getting it right since the change in angles are so small. I doubt the set fins are that accurate anyway(how do you consistantly keep a .3 change of angle when routing, setting FCS plugs in oversized holes, setting in resinsoaked glassrope with only a flimsy piece of tape, etc.) Secondly, through trial and error, for the most part, setting the fins to point at the nose just works.

regards,

Håvard

7

why is this a mystery rob?

is this just more shaper mystique?

post some more information (rocker and outline pics) of the board, the type of waves they were designed for, the intended rider’s surfing style, and how control v. speed was factored in and maybe some of us could explain it to you

or is it simply taste?

i dont like that much toein on my boards…too much drive loss…i prefer 1.5 inches offset nose tip…but hey thats just my personal taste

isnt it interesting…when people spec board dimensions they always mention planshape specs but almost never a mention of rocker specs and more importantly its curve(s) …rocker…the silent majority

Here’s a good follow up question…

looking back almost thirty years, why is it that when a pop mag ran a story/profile of a famous shaper, the shaper always appears holding a Skil 100?

why not a sanding block?

or a mini-block plane?

where they just throwing everyone off the scent?

the ‘modern’ thruster has been with us for almost 25 years now…it is THE performance standard…why are there still ‘mysteries’ with regard to its setup?

8

bill im flat out but i really want to throw my bit in before you give the final word …

so dont give us the goods till i get to give the run down …

thanks

regards

BERT

9
Quote:

For a board with fins set at 12" and 1 1/4" in from the rail and fins toed to the nose

6’ length 13" tail is 4.17 degrees

7’ length 13" tail is 3.57 degrees

8’ length 13" tail is 3.13 degrees

6’ length 14" tail is 4.56 degrees

7’ length 14" tail is 3.91 degrees

8’ length 14" tail is 3.42 degrees

All of these are substantially too large. The end-limit for shorter boards in a thruster config is very close to 3.2 degrees.

I’ve seen shapers reduce toe-in on bigger wave boards, and had shapers reduce the fin chord length and keep the depth and toe-in preserved. I prefer the latter, although if you use 3 identical fins the former is preferred, of course.

If you do much playing with fin toe-in you will readily make your own observations…it ain’t that hard, but it takes a little time and effort.

10

Actually my calculations was a bit off, but I’ll correct them. But then they get a little worse… I’m not saying that these angles are the correct for all applications(rocker and template leaves alot to be desired). I’m just saying it’s better to reference toe in in relation to the nose as it’s easier to make small adjustments and make it accurate. 1/16" change in toe in is the same change in angle as doing a 1’ longer board with toe to the nose.

But let’s do it again with the numbers on the original post.

6’6, fins set at 11 1/4" up 12" apart, toed to the nose… I get 5.1 degrees

6’9, fins set at 11 1/4" up 12" apart, toed to the nose… I get 4.9 degrees

7’0, fins set at 11 1/4" up 12" apart, toed to the nose… I get 4.7 degrees

Or isn’t the angle here the same as the oposing side divided by the ajectant side and then do an inverse tangens? (f.ex invtan(6"/(6’6"-11 1/4")) )

I’m going with an adjustable fin system on my next board, regardless

regards,

Håvard

11

5.1 degrees!? no thanks i’ll pass…

to clarify my comments to rob earlier:

toein at the nose tip or a slight variation in and out of that has been the std for a long long time…no mystery to unlock

i agree with blakestah on angles…less toe more drive and projection…for tighter radius turning more toein is a bit better and smoother…were talkin only 1 to 2 degrees difference here

if its still a mystery, go with the available adjustable toein boxes in the market…eliminate any mysteries in no time

im set after some experimenting myself

12
Quote:
5.1 degrees!? no thanks i'll pass...

to clarify my comments to rob earlier:

toein at the nose tip or a slight variation in and out of that has been the std for a long long time…no mystery to unlock

i agree with blakestah on angles…less toe more drive and projection…for tighter radius turning more toein is a bit better and smoother…were talkin only 1 to 2 degrees difference here

More toe-in loosens the tail. The best riders, on highly rockered boards, reduce toe-in (from the standard), as that allows tighter radius turns. The rail fin begins to hold at smaller angles of attack of the surfboard.

However, “thrust” is optimized with a slightly larger toe-in, at the industry 1/4" standard. If you use a 5/16th toe in, the board will whoosh through turns, having a substantial loss in turning radius. And if you use a 3/16th, the board will turn more quickly, but the thrust will diminish. At 1/8th, I cannot feel thrust at all.

1/4" toe-in applied to a 4.5 inch length is 3.18 degrees.

A change to 3/16th inch is 2.38 degrees, a 0.8 degree difference.

Whereas one may claim a 1/16th error in toe-in makes the difference from a great board to a dog, in reality it is fairly easy to make this work if you simply draw a coupla dots on the board with the measured line, and make sure the fin, or a blank, is held in place while the boxes set.

Toed-to-the-nose on a 6 ft board with the rear of the fin 1 inch off the rail and a 14 inch tail is 6 degrees, which is way too much.

Toed to three inches outside the nose is a little bit more ballpark.

HTH.

13

More toe-in loosens the tail.

yup with ya on that one…

The best riders, on highly rockered boards, reduce toe-in (from the standard), as that allows tighter radius turns.

Too much toein on a heavy rockered board = DOG!

But put some smaller front fins and some good near world class surf and youve got rail surfing majic…given the ideal combo of board, rider and conditions

However, “thrust” is optimized with a slightly larger toe-in, at the industry 1/4" standard. If you use a 5/16th toe in, the board will whoosh through turns, having a substantial loss in turning radius. And if you use a 3/16th, the board will turn more quickly, but the thrust will diminish.

optimal AOA…or best allround position to minimize flow seperation…which is highly dependent on wave conditions, particularly wave face shape, and the rider’s board placement on said wave face…ie style

At 1/8th, I cannot feel thrust at all.

Massive flow seperation in effect countering other benefits of said toein…???

Toed to three inches outside the nose is a little bit more ballpark.

yup, especially on wider tails…my everyday boards vary from 14.4 to 14.9 wide

here’s my bottom line…GENERALLY, slightly less toein more powerfull drivier bottom turns, slightly more toein better easier smoother top turns…

14

It’s kind of funny because you seem to be arguing but actually agreeing.

here’s my take:

-toe in to the nose on a 6’ board: too much angle

-3" of the nose: better (close to standard angel normally used)

-more toe in: looser

-less toe in: faster

how am I doing so far?

going back to the original post, all 3 boards mentioned are longer than 6’6". this means their angle is lower than at 6’3" (3" off the nose of a 6’ board).

this emans it’s probably in the right ballpark, leaning more to the ‘faster’ side.

my guess is that, for boards longer than a certain size (without oing all the way to longboards), toe in to the nose delivers a balanced solution for that lenght (a shorter board is looser by definition, as a general rule, and a longer board is for higher speeds and draws longer arcs)

15
Quote:
bill im flat out but i really want to throw my bit in before you give the final word ...

so dont give us the goods till i get to give the run down …

thanks

regards

BERT

No worries Bert. I am not jumping in to this for awhile yet. All the ideas and theories are great! I can’t wait to read more.

16

Do any of these numbers still apply with a thickness forward/symmetrically foiled leading edge fin? I’m thinking specifically of Halcyon’s custom foils and FCS’s new forward edges.

Would seem that a fatter symmetrically foiled leading edge allows a wider range of AOA without being as sensitive to specific toe in angle. When going straight through flats or around sections, the more toe in, the more the fins are working against each other. Does it seem logical to be dragging fins sideways through the water?

Is the Blakestah on to something hot with his variable toe in system? I.E. straight ahead in “neutral” and toed-in during turns? (I’m dying to try those)

What about 4-way fin systems?

Clyde Roger’s Rotatable Edge Performance System?

Sab’s home made adjustable toe-in plugs?

(http://www.swaylocks.com/forum/gforum.cgi?post=186086;#186086)

17

I generally agree with Jimthesaint but I have used the Edge sysytem and these measurements are not something that should be carved in stone. I’ve gotten to play with this quite a lot thanks to the Rodgers boys and very much depends on where your surfing and what you doing. Get a very down the line wave like Pavones and I would use the fins almost straight. Meanwhile at a peak you like Sebastian you’d use more angle. On some waves the fins could actually be set each different. Straighter for a strong bottom turn and more angle for a tighter line off the top. The standard measurements IMO are a median setting meant to work well in a variety of conditions. Again Balance… Fin angle effects mostly resistance balance.

18

Ok Bill!! It is time for you to explain. Please…

Also, even though I copied your template and fin angles, my boards were extremely slow down the line, so your

rocker must be EXTREMELY important in relation to the fin angles.

I am also suprised that so many shapers use absolute (1/4" , 4 degrees) measurements when laying down the toe-in.

Thanks.

Rob Seppanen

19

dam im so pushed for time ,

so here comes the quick version …

i would consider that amount of toe in more than my average …

as a general rule most shapers will tune for there average conditions so if i had to compare those setts to something i would build , they enter into the realm of fin setts for solid waves …

as the waves get bigger we are going faster ,that means when we load into a turn ,the water wrapping our fins is doing so at higher speeds …

template aside , 2 things will have a bearing on the point at which our fins will fail and start losing hold and sliding out …

1 the angle of attack …

2 the speed at a critical angle of attack …

for our fin to work effectively water has to stay attached to both sides of the fin …

on a thruster , when we bank onto the rail ,our one side fin still in the water is starting to take the bulk of the load …

changing toe in angles affects the angle of attack …

less toe in means a higher angle of attack …

more toe means a lower angle of attack as we turn …

remember that a fin or wing to maintain lift and hold has to stay within its threshold of AOA and within a speed range …

the faster we go the easier a fin will slide out at a given angle of attack , so if we reduce the angle of attack we can comfortably push our board into a turn at speed without sliding out and having the fins fail …

to reduce the angle of attack we increase toe in …

there is also another aspect …

the faster we go the more lifting force a wing generates …

same on your surfboard side fin/wing …

now lift is good sometimes …

but to much turning/lifting force at high speed and your board can become over sensitive and sporadic at high speeds …

so increasing toe in , reduces the turning or lifting force in the early stages of the turn so it wont over steer and pull to hard and fast into a turn if we just want to do a drawn out turn at speed , but it will allow us to push the board in harder at a more critical angle through the later stages of the turn and the fin will still maintain hold , which translates to drive out of your turn because your fin is still functioning while your pushing your board tighter …

if we didnt have enough toe in , then we would over steer at speed and if we didnt lose it then , we would probably go into a drift through the later stages of the turn and then lose all our recovery time , thus not setting up cleanly for the next turn …

now the posistioning of the fins …

further forward , means we stand further forward to turn …

further back means we stand further back …

same , at speed we naturally stomp on the tail more through tight turns , we need to get the tail to bite and get some hold …

setting the fins back makes the board feel more comfortable in solid waves …

there are a number of related issues , but time is working against me …

i run a range of 6mm or 1/4" difference from the least amount of toe to the most amount , depending on what the board is being designed for …

if i had to generalise , without taking all the other varibles into consideration …

those fin setts mentioned above would go into boards that i would make for someone surfing our southwest , which has speed and power …

all the boards originally mentioned fell within a narrow size range …

i would be curious to see what bill did as the board got up to 9 or 10 ’ (not longboard)

as that would decrease toe in substantially …

now one thing that wasnt adressed was foil …

because that changes the rules again …

depending on the foil , we can still decrease toe in and not create a sensitive sporadic feel , but the down side is , it wont handle the real hard angles of attack as well , but in 9’ plus boards the shear length of rail line , will be a limiting factor to how tight we can hook it and load the fin anyway …

honestly bill , i know i havent covered 1/4 of it , buts its all i can fit in at the moment …

regards

BERT

hey just finished this one a few hours back …

trying a new finishing rapid dry clear …

not bad …early results are promising …

20

At a pure guess tow in pointing straight to the nose would work better on a board with more relaxed tail rocker. Most of the boards ive ridden in recent years have had a fair amount of tail rocker and when ive tried experimenting with more tow in the fins it just didnt work very well at all. Quick rail to rail transitions but difficult to get and hold speed to get through sections. Ill try it again on a board with less rocker when i get some time.

Some surprising observations (for me) while experimenting with tow angles and the 4way fin system on a few boards

As others have mentioned tiny changes in tow make a difference…i was surprised at how little. maybe 1mm seems huge

The tow on the left outside fin loosens or tightens the turn going right and vice versa going left.

asymetrical tow angles works pretty well when your going only right or only going left.

there is no magic tow angle or placement that works for all boards and waves and riders

so many damn variables with fins, fin size, shape, foil, camber, placement/cluster, tow in…AHHHHHHH! brain overload…then getting it all to work well with a particular board. especially a board type youve never shaped. For me I dont longboard so when I decided to shape one it was looking at where other people put the fins and then…UGHHH best guess…live and learn.