Single fin question

[coldsup]

The saying is one inch per foot of board....that’s length wise.

Is there a rule of thumb for how deep a single fin should be to stop it spinning out if you were banking hard on a rail? Eg if you had a wide tailed board?

[burchas]

Other considerations you might want to take under account are tail rocker and fin box placement.
For instance, if your board has a lot of tail rocker and the fin box is placed very close to the tail you'll need
extra length to compensate as you might have much less area engaged.

Another option is to go with a fin with more area rather than depth, so a fin with 60 Square inches of area
but 7-8 inch deep rather than a 12 inch deep with 50sqi might feel better for you with your wide tail (if tail rocker is
low)

Other considerations would be fin template and flex profile. Some fins with a lot more area in the tip might feel
better to you and some fins with a good flex profile where the last third of the fin has some flex in it might do the
trick as well, allowing you to recover your balance.

[surfcowboy]

I need to see pics of you laying enough rail to pull an 8" center fin out of the water before I can reply.

Seriously though, how wide of a tail do you have on a board set up to be a single? That strikes me as a curious design. Most wide tailed boards have side bites for that reason.

Also, have you slid the tail? It doesn't hurt to try and see what happens. One of my most educational sessions was running my quad board as a twin with tiny fins on a knee high day. Fun session and interesting to see what held and where and how.

[surfinJ]

I love single fins on longer boards. But the none of mine have a wide tail.
There is no rule of thumb for fin size. A vintage noserider has a very large fin but the modern shaped fin is substantially smaller.

The range of longboard fins I use is from 6.5” to 10” with probably the 7&8 getting the most rotation. If you don’t get back on the tail the smaller fins won’t add much, otherwise they’re looser. Nose riding and surfing from the middle of the board will probably be more effected by where the fin is, fore or aft.

Although it is possible to break a single fin out in a turn, it’s not easy and you were probably going down anyway.

[coldsup]

Thanks gents......it was something I was discussing with a friend...curiosity really. I’ve never slipped out on a single but then I would never have my big board on such a steep rail as I tend to surf only small to medium waves. I mostly ride it 7 inch single with 3.5 sides.

Love singles though too.

[surfcowboy]

Coldsup, got it. I'm no fin master by a long shot but the only boards I've ridden as a single have has some sort of relatively narrow tail, rounded pin or swallow. The wider tailed boards I've ridden have all been set up as quads or twins so I can't really speak to their function.

But from what I've gathered from my minimal shaping and longboarding experience is that you are probably talking about a combination of tail shape/size as well as the single fin when you're saying "I love single fins" as those elements are linked in most boards.

By that I mean a Simmons shape set up with a single fin isn't going to ride like a classic longboard with the same fin.

What is the board you are talking about here? What's the tail like? I'm intrigued by this question even if I don't have the answers for you and I'd love to hear what the other more experienced shapers here say.

[coldsup]

Coldsup, got it. I'm no fin master by a long shot but the only boards I've ridden as a single have has some sort of relatively narrow tail, rounded pin or swallow. The wider tailed boards I've ridden have all been set up as quads or twins so I can't really speak to their function.

But from what I've gathered from my minimal shaping and longboarding experience is that you are probably talking about a combination of tail shape/size as well as the single fin when you're saying "I love single fins" as those elements are linked in most boards.

By that I mean a Simmons shape set up with a single fin isn't going to ride like a classic longboard with the same fin.

What is the board you are talking about here? What's the tail like? I'm intrigued by this question even if I don't have the answers for you and I'd love to hear what the other more experienced shapers here say.

Very similar shape to a Fanatic Fly but more performance....more thinned out tail and nose with more rocker too. 10 x 31 ...I guess the tail is around 19 inches wide using the 12inches up from the bottom of tail rule. Rounded pin

[surfcowboy]

Taking that width, and assuming you aren't Dane Reynolds, I'd say that anything over 7-8" should be fine but I'd go bigger for that board, myself.

If you can, borrow a bunch of fins from friends and just swap them in one day. I used to leave tools and fins in a towel on the beach when I tested fins so I could swap after a few waves.

[coldsup]

Taking that width, and assuming you aren't Dane Reynolds, I'd say that anything over 7-8" should be fine but I'd go bigger for that board, myself.

If you can, borrow a bunch of fins from friends and just swap them in one day. I used to leave tools and fins in a towel on the beach when I tested fins so I could swap after a few waves.

Take it you mean any SINGLE over 7 or 8 deep would be okay.....I’m using a 7 with the smallest sides I have just now. I would use a 10 inch single though.

P.s. I can confirm Mr Reynolds might have better skills than I. 

[Subber]

Is there a rule of thumb for how deep a single fin should be to stop it spinning out if you were banking hard on a rail? Eg if you had a wide tailed board?

My experience is that it is the width of the fin (more at the base than the tip) that is more important as far as spinning out.
I have a few pretty narrow but still tall single fins that I run sometimes - they work pretty good for nose riding
(which is what i got them for)
but I can't really push it if I want to go top to bottom or I will spin out.

On my board with 3 boxes, the solution is to add a side bite, or get a wider fin.

This is pretty much the same for 2 + 1 setups.  If the total width of the three fins (at their bases) is too little,
I will slide out when pushing a bottom turn hard.   So I increase either the side bites or the center fin.
but, as far as sliding out, I think it is the width more than the height.

[surfinJ]

These are what I use, thicker at the tip. Very loose and and yet holds when pushed.
A 8,9 and10”. Shaper of the fin is Wingnut, a longboard pro.


They don’t spin out. 
 

[PonoBill]

I like tall squirrel fins for noseriding (or rather, near noseriding), but a square tail seems to kill the ability to turn the board from the front.

[Subber]

I like tall squirrel fins for noseriding (or rather, near noseriding), but a square tail seems to kill the ability to turn the board from the front.

That's interesting.  I can steer fairly easily from the nose on my Laird, but it is a pintail.
But, I can also steer well from the nose on my Black & Blue and it is a square tail, but
the B&B has a lot, I mean a lot, of tail rocker.  So, I wonder if that is the difference
between it and yours.

I've read a few times that big tail rocker helps hold the nose down, but I'm not sure I believe that,
although, I do think it makes a board easier to turn from the tail; now maybe from the nose.

Is your's the Foote?  I'm looking at a used, older, Foote longboard SUP right now.
I've not seen it in person yet.  I wonder if it has less tail rocker and if that
makes noseriding easier as far as getting further up on the nose, getting toes over.