Fin Alignment: Measurements, toe, etc ...

 

Quick question about fin placement/alignment:

 

On my board, the fins (FCS) are the same distance from the stringer at the front. But the left fin sits about an 1/8" further than the right fin does in the back. Thus adding a bit of extra toe on my heel edge (goofy foot). I have had the board for months and never noticed anything. But, I have always had trouble with the board on frontside carves. It wasn’t till I was describing the ride issues with another shaper/friend told me to check the alignment.

Do you think a being off a 1/16 - 1/8 of an inch would affect the way a board rides for a mid-level surfing? Furthermore would something like this merit a plug reset or other fix?

Anything about the fins can seriously affect how a board rides, even 1/8".  That said, the heel side fin shouldn’t have very much affect on front-side bottom turn as it usually is not engaged if you are turning the board hard enough.  If you are not getting the board up on edge, on a front-side turn, the heel-side fin may still be in the water and cause a little drag and pulling the board back toward the heel-side rail.  But that would occur regardless of whether the toe-in was symetrical or not.

If it was a big issue, I would imagine you would feel it more when you are paddling or dropping in.  You would feel the board pull toward the heel-side fin.  If that is not a problem, then the difference in toe-in isn’t a big deal.  In fact, it may help you on back-side moves like cut-backs.

If you like everything else about the board, try changing the fins.  Try using different fins on each side of the board.  I’d try that before relocating the plugs. 

Great advice Lee, Thanks. I have been mixing things up a bit in terms of fins with the board. Previously I had chalked up the issue to: NOT driving off my back foot enough. Making the adjustment on the fly to use my back foot more on the board definitely seemed to help things a bit. I have always like the board on my backhand (especially on waves with space). I just thought it was interesting that my buddy pointed out that I should look into it… I get home and it was a tad bit “off”. 

At first blush I figured there was little to no chance that 1/8" of extra toe under my heal would meaningfully impact my surfing. But since I’ve been frustrated with my turns on that edge I thought their might be a coorilation. Mainly, I wanted to get the opinion of some experts as to what was considered “off” versus an acceptable variance (since boards are hand made). With my limited shaping experience I would be thrilled to accomplist symetry within 1/8", but on a $600 board … I have no point of reference. 

Currently the rest of my boards in storage so I dont have access to another board to use as a proxy. I imagine that once I do, it will be MUCH easier to decipher how much of the problem lies with me. 

If you end up re-aligning the boxes, you might consider toeing the toe-side fins to match the heel-side fin rather than the other way round…

If you want to see the real effect, take a long straight edge (do you have a rocker stick?) and lay it over the boxes and see where the stick intersects the nose.  Most people measure the toe-in based on how far off the stringer (at the nose) the straight edge is.  I think that is a better indicator of the possible affect on performance than measuring from the stringer to the aft box…If you have a short board, the stick should probably not hit the stringer at the nose or you could be pushing water.  Every designer has a different distance to the stringer and it will depend on the boards length and how you want it to surf.  Ultimately it’s about angle of attack but in general, more toe=shorter turn radius.  Less toe=move drive and longer turn radius. 

The board is a shortboard. I will try to capture a dimension when I get home, I am sure I can track down something to make the measurement (I am thinking a vertical blinf will do the trick), although… as you pointed out, on a short board they will likely not intersect (based on how I was measuring previously they run pretty close to straight). 

 

Question:
When a dimension is provided for “toe”: Does it generally refer to the line drawn from the fin box and the distance from the nose that the line intersects the stringer?

And the standard of that measurement seems to be 1/4"

*Update: Found this - http://www2.swaylocks.com/comment/1282263/Re-brasco-Whats-deal-toe
I will be measuring this evening.

The “standard” is not really a standard unless you only use one kind of box since the measurement is the difference between the distance from the forward box to the stringer and the rear box to the stringer.  A little geometry will show you that the 1/4" means different things depending on the length of the box or whatever you are measuring.  Toe-in should be really be measured in degrees from the stringer as that is independent on the box length.  Unless you have the right tools or templates, transfering the measurement in degrees out to the actual box location can get messy.  That’s why I use the rocker stick…fairly fool proof and repeatable.

The pros have templates and jigs.  If you make enough boards; that’s the way to go.  

Oh yeah…If you go into a shop and pull 10 thrusters out of the racks, either by the same manufacturer or different, you will be hard pressed to find a board with the fins installed exactly like they should.  There is just too much room for little wiggles or scoots between the shaper and glasser; stuff gets off.  Especially when they are being mass produced.  Your best bet is glassed on fins since its pretty easy to tack the fin exactly over the shaper’s mark.  And that is only as accurate as the shaper’s tenacity in measuring a marking the fin locations…

Ride a single fin and eliminate two thirds of the fuck-ups!

I’ve got 3. One day I will pick up a 4th more functional version.

 

hahaha 

In order to get real measurements I think I need a tool, but using crap I had laying around the house I got:
Port: 3"
Starboard: 3.25 - 3.5"

The above is the distance from the stringer at the nose after attempting to make a straight line that followed the fin boxes. The board is a fat stubby thing, thus pretty wide at the tail. I did get some measurments with bigger discrepencies, bit the above seemed to be the median.

A potential for an easy fix exists... simply scrape the inside leading edge of the fins with a single edge razor blade to reshape your own "80/20", "70/30", or beyond.  Whatever you want to call it, a more blunt and more symmetrical leading edge allows for a wider range of angle of attack without interfering with the flow. 

There is a reason why Skip Frye and others utilize a straight ahead, straight up and symmetrically foiled twin keels on their fishes. 

In any case, a smidgeon of body english here or there should allow you to easily compensate once you get the hang of your specific board.  As Lee points out, most side bites on surfboards are off to greater or lesser degrees.  I'd be more inclined to suggest a change in position of your rear foot than to go ahead with reinstalling your plugs.

Frankly, I doubt that 1/16 of an inch is going to be noticeable.  1/8 of an inch?  Maybe for a pro level surfer but still negligible.  

WATER IS STUPID! 

 

I’ve found water to be playful one day and a cruel mistress the next.  It has to be coaxed, cajoled, and occasionally caressed.  It has a short memory but vaguely predictable… Stupid - no, stuborn -maybe, fickle - always.

Well - I'm no Occy (more like Edna everidge really) but I've experimented a lot with toe (using the 4wfs) and1/16" is very noticeable past a certain point.  That is, 1/16" too much turned a good board of mine into a total dog - felt like I was surfing with the handbrake on.  1/16" too little and it became quite tracky.  I found toe in to be very critical and expereinced real differences resulting from very small tweaks.

The actual measurements are rough without the the tools to do it right. I’ll probably run it over to a local shaper and have them take a look at it and get me some real measurements.

I took some actual measurements this evening and did some math:

 

**PORT**

 

 

***Nose aim point - 3.75"**

 

*Angle - 2.39°

Front - 5 15/16

 

Back - 6 1/8

 

 

--

 

**STARBOARD**

 

***Nose aim point - 3"**

*Angle - °3.18

Front - 5 15/16

 

Back - 6 3/16

 

 

(Nose & Angles generated using 6th grade geometry)

 

 

What matters now is you have a reason to go back and complain to the guy whose name is on the board so you can complain, and think he owes you something.  There is probably much more  you can complain about to the guy, and in fact you can tell everyone you know what a crappy person he is because your fin is off, according to your measurements.  I have owned more boards than most people on here, and ridden them in all kinds of extreme conditions, and guess what, sometimes the fins have been a bit off.  I used to be a great surfer by many others compliments, but am quickly becoming irrelevant, but my experience has taught me to adapt, and learn from all the subtle variables that end up as the surfboard under my feet.  There is not a perfect board for every condition, and many surfers end up blaming the board for their own lack of ability.  So hide behind your belief that your mediocre surfing is marginalized by a mis-set fin placement- what a sissy.

I have gone out of my way to NOT bring up the shaper and as I have mentioned several times that I have no intention of doing anything besides potentially fixing it on my own. The ONLY reason I intended to POTENTIALLY talk to the shaper is because he is a friend and therefore might be interested in the outcome. The whole reason I have been looking into this was to LEARN something about my surfing. As you said “… to adapt, and learn from all the subtle variables that end up as the surfboard under my feet”. I stated several times that I was positive this was so marginal it couldn’t impact my surfing at my level. Did you even bother to read this thread before commenting on it?

 

Congratulations on having owned more boards than most people on here.

Oh yeah, I read it, and understand more than you know.  I’ve paid my dues way too many times, and made enemies for my frankness.  Your making a big deal out of nothing, so perhaps you should “fix” it and your surfing will magically improve.  As bad as my surfing is these days, I bet mine is better, even switchfoot.  Experience doesn’t come overnight, and insight comes with experience,as well as, intellect.

Thank you for your frankness. I appreciate it. I also agree with you. That’s why I am not really sure what the fuss is about.

The purpose of these threads it to discuss surfboard design. That is exactly what is happening here. As for the attacks… The bottom line is you have no idea how I do or don’t surf. If you surf better than I do… Awesome.

[quote="$1"]

I took some actual measurements this evening and did some math:

 

PORT

 

 

*Nose aim point - 3.75"

 

*Angle - 2.39°

Front - 5 15/16

 

Back - 6 1/8

 

 

--

 

STARBOARD

 

*Nose aim point - 3"

*Angle - °3.18

Front - 5 15/16

 

Back - 6 3/16

 

 

(Nose & Angles generated using 6th grade geometry)

 

 

[/quote]

Hi redreef -

In all honesty, I'd say you're good to go.  With the trailing edge 1/16" off as measured across from the stringer, I'd say the offset is negligible.  Measuring to the stringer at the nose can be deceiving as few stringers are perfectly straight.  A stringer even slightly bowed will throw your fin-to-nose angles off by a lot. 

Try measuring some other boards and see how many are off by at least as much.  I'd say don't overthink it - just ride that thing.