Up to now I have just been marking my toe-in as fractions of an inch along the fin base… as in: toed-in 1/4" …
I have read numerous posts by shapers who measure by going a distance ‘x’ off of the nose. I tried this the other day when I was finishing up a shortboard;
6’4"x 19" x 2 3/16"; with a quad setup. I decided to try out the different method, using the strait edge on the back of one of my templates, and going with 2" off the nose for both the front and back fins. Only thing is they looked a little extreme for toe-in, and when I checked, the front was 3/8" and the rear was 1/4". Is this not a little too extreme? for reference the fin placements are: rear-5 1/2" up, 1 1/2" off rail; front-11 1/2" up, 1 1/4" off rail
Now, I am sure that someone could chime in and give me numbers to use on this board, but what I am wondering is; what is the ‘golden rule’ is that applies to using this method?
I could go on just doing fractions along the fin base, but it seems upon reflecting that by measuring off the nose you not only get a wider set of increments, but perhaps it flows more with the overall board measurements.
I lined up the strait edge of my template on the trailing fin mark, and then lined up the other end at 2" past the nose, along a square that I was holding on the board.
I’ll admit it was a tricky way to be doing it! But I want to find out how it works…
I’ve always measured using a square at the nose , 2" off to the side ( oon either side of the stringer), not in front. I tried in front but the toe seemed excessive
I’ve always measured toe-in “off the nose.” I use a long straightedge and line up the fin dot with the measurement I want. Having somebody hold one end on the dot while you adjust the angle really helps.
There are a lot of variables to think about when deciding to do the toe-in. Tail width, distance from rail, length of board… are factors I consider. For high performance thruster type boards, I toe in straight to the nose. For one-sided foil keel fins on short, wide fishes, I’ll go out to three inches or sometimes more off the nose.
So in terms of a golden rule, I don’t have one. But I can tell you that you’re numbers are in the range of some pretty common quad designs. The only thing you didn’t mention is single or double foiled fins (or both) and cant. Generally, single foiled fins are toed and canted more than double. What kind of fins? Canard? Thruster type?
For this board I went with 6 deg. cant for the front and 2 deg. for the rear. I have a set of future fins (molded), the Jon Carpers I believe, 4 1/4" high, and I just got an extra trailing fin to make up the rear pair. What I am planning to do though, is to make a batch of fins, and for this board do a similar set for the front, but a smaller set of single foiled fins for the rear, as well as a couple of sets of canard quads for some fish that I have/will be making.
I installed the boxes today, and yes, they do look right.
I guess the eye is the best tool to sharpen up in the shop eh?
For a quick look at how different aimpoints in relation to the nose effect the toe, I wrote a program that does the calculations for you, taking board length, tail width, fin size, etc, into place. Check out the calculator at http://www.kainoalani.com/design/toecalc.html. Feel free to reuse it on your own site.
Johan1 - I think you’ll find anything over 1/4" toe in per fin to be too much. I’ve ridden boards that had more - they turned tight but you could really feel they drag- they just lost too much getup and go. For 6’ to 6’2" range I like 1/4" toe in per fin . For 6’4" to 6’6" I like a total of 7/16" and my 7’1" semi have 3/16" per fin. I’m very comfortable now with these numbers. Rick Hammon got me using the numbers instead of the off the nose approach. More precise. Also you really only surf the back half of the board so I think it’s more about the rail/fin relationship and wave size not length of board- which can really distort fin toe in measured off the nose.
That calculator is great, thanks! All three ways to measure are covered with it. Change in measurement from stringer, line to point in front of nose, and degrees of toe in…cool. Personally, I think angular measurement is the most universal for measurement of toe (and cant).
Kainoalani - nice tool! I compared 3 of my board’s fin toe in placement to what you’re calculator suggested and I’m impressed. My 6’2" was the same, My 7’1" semi was the same and my 6’5" is real close - I have it at 7/16" total toe and your calculator suggested 1/4" per fin, only a 1/16" difference total. I would hope you’re tool does not get lost in this post only, but could be put in a wiki type place with other good ideas-very creative- I’d love to see what you’ve come up with for canting - Regards - Pat Reen
I gotta say, the thruster rail fin toe measurement off the nose has always made little sense to me, except as a rule of thumb that gets you in the ballpark for a given length, since the fin interacts with the rail edge right next to it, not the nose, except much more indirectly. The width of the tailpod vs. the WP, the length and curve of that stretch of rail, any V, rocker behind the WP all have way more to do with the fin’s toe-in being right.
The fin’s effectiveness if measured off the nose can be skewed by any asymmetry in overall template, like WP back or forward, or a really short length (eg: the original Lis short twin keel fish, if applying the same logic to those rail fins, would never have been the magic board it is, it would have lost all its speed and magic), since the rail line’s curve behind the WP will tighten or slacken with any non-centered WP (and with changes to the tail pod width). The rule of thumb works at all because length of boards generally slackens the rail lines and the reverse is also true.
Not concentrating on the interaction between the rail fin and the rail right next to it, the thing it’s working directly with, well, I have a conspiracy theory involving Merrick but forget it…
janklow- please continue- I can’t handle the suspense, and I agree - you surf the back half of the board (mostly) unless you’re on a fish carving like hell and using a lot of rail AND I find Kainoalani’s tool very interesting for typical thruster/ semi-guns- from my limited experience. - (ps - you’re not gonna get flamed by me - no time for that crap!)