Or smaller fins further back?
What difference would there be in performance if placed on a slightly shorter, wider tailed High Performance shortboard? (Like an AM Flyer)
It’s hard to answer a question where you’re changing two variables. But the short answer is that,
for the type of board you describe, moving the front fins back a little loosens the board up. The
trade-off is that you lose some drive. But that’s usually acceptable in a small-wave board.
thats just the opposite of what i thought…?
I’m no fin guru, but here’s what I do know…
Front fins that are too big, or too far forward, can make the board too responsive… or “squirrely,” and lack adequate control. It will feel too twitchy, and throw off your timing.
Front fins too small will not be responsive enough, and will have less drive than appropriately sized fins. It gives it a “soft” or mushy feeling, like fins that are too flexy.
Front fins too far back will lack responsiveness, but be more drivey, but can also affect your timing.
Front fins that are too big and too far back will be really stiff, but really drivey, and, again, throw off your timing.
So I guess the moral is: fins should be of adequate size(s) and put in the right place(s)?
Now, seriously, I too would like one of the fins gurus to spend some time on this topic. I’ve made a few quads and I relied on Bruce Mc Kee’s indications for placement and angles (why not trust someone who’s heavily into it?) but some well-documented explanations would be most welcome.
Think of fins as the pivot point of your turn. If they are forward of your back foot, your turn will be more of a pivot, more of a spin like a top. By this I mean that the board will change it’s orientation (the direction it is pointing) but not the direction it travels. Fins in front of your back foot will feel more like a spin.
Fins behind your back foot will make your motion more like an arrow. Feathers are placed at the back of the arrow to create drag and make the tail end go slower than the front, thereby making the arrow fly straight. The farther behind your back foot, the straighter the board wants to go.
The best part of a custom board is that it’s sized for you. Its design is to put you standing on the board where it will give you the most benefit. First decide what kind of turns you want to make. That will tell you where you should stand in relation to the fins. Design the board so that its natural position will have you placed where you want to be.
Have you ever had a board where on the take off, you always seemed to jump up and end up too far forward? That’s beacuse your best paddeling position didn’t work with the best standing position. If a little of the floatation was moved back, you would paddle a little further back, and your natural movement would have landed you where you want to be.
Start with whatever board you are currently riding. Next time you catch a wave, look down at your feet and see where they naturally landed. Place the fin and size the board accordingly to get the turn you want. Long and drawn out? Put the flotation in the board where you need it to get you standing with the fins a little further back. Tight pivot with less speed? Add foam to the tail and less up front. Its all a matter of where you stand on the board, and less with where the fins are. After that is done, fine tune the board with fin sizing.
By the way, rocker is a HUGE factor in all this.
Quote:
Or smaller fins further back?What difference would there be in performance if placed on a slightly shorter, wider tailed High Performance shortboard? (Like an AM Flyer)
Here is the best I can do for ya’.
2 boards within 1-2-3" of length are equivalent for this discussion.
YOu have one board and the fin positioning is good and set.
You have another board,same as the other, only with a slightly wider tail.
Fin positioning for the wider tail board:
Several options:
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cluster gets moved back slightly: preferred
-
use same fin positioning but slightly larger side fins,
then figure out what works in the rear.
I cant’ make heads or tails of what the other guys wrote.
Wider tails need either bigger fins or same fins moved back
to get your control.
Narrow tails(hold better)…so consequently, you use smaller fins or move the cluster further forward.
…Make sense?
Narrow tails(hold better)…so consequently, you use smaller fins or move the cluster further forward.
Maybe, Maybe not. Narrow tails ride deeper in the water. That moves you forward to balance the board to level. That puts the fins further back from you. That makes you go straighter!
Narrow tails are easier to sink. Sometimes that’s good and sometimes it’s not. It all depends on what you want the board to do.
Narrow tails are easier to roll side to side and put on a rail. Sometimes that’s good and sometimes it’s not. It all depends on what you want the board to do.
Geez, someone who posts a question to swaylocks and knows little, has all this stuff, some of it contradictory thrown at him.
THE QUESTION IS FOR TWO NEAR IDENTICAL BOARDS!
KISS PRINCIPLE. KEEP IT SIMPLE S.
Thanks Everysurfer
For those that don’t visit the er BB, this was what I posted over there:
Fins preform two different functions. One is directional control and the second is kinetic propulsion. These two functions optimize in opposite directions. If all you wanted was directional control (like when you are surfing waves with plenty of power to spare) smaller lower drag fins will perform better. Note also that when you are surfing powerful waves a narrower tail and fins further aft will also improve the directional control if that is what you are looking for.
To maximize kinetic propulsion (weaker more grovelly surf) you want to grab as much water as possible and push it out the back. Bigger fins with either flat or concave inside faces will help pump up the volume better than a low drag fin the sheds water more efficiently. These types of fins also work better in wider tailed concave boards that develope more lift. But, these fins become draggy once you start to haul ass. There is a lot of middle ground inbetween. But, as a general rule of thumb if you are grovelling go for a fishy type board with big side fins and a smaller trailer. And, if your’e surfing big square sucking barrels that are just at or above your comfort level pull out the gun and stick smaller more efficient foils in that sucker. 
…however, Occy and T Carroll fins are big with wide base too
and for surf stronger conditions
and most 80s fins were big and plenty of heavy surfing style in those years
Now you’re getting into a matter of style. Have you ever seen Occy’s or Tom Carroll’s legs? They’re friggin tree trunks proportionally to their bodies. If you’re gonna treat a DOH Pipeline wave like your local waist to head high beach break and have have the legs to push it through. By all means go for the big fins. I’m sure not going to tell them not to!
Sorry Otis,
I will be sure to use smaller words next time. Oh, and I will also tink dat da dude righting da post jus want a little bit o help ;-D
Thanks for the replies everyone!
Here is the deal with the board. I have been riding it with some fuller tipped, slightly more voluminous fins (ala the K2.1 side fins) They are single foiled and pretty stiff in flex.
With these the board has felt closest to how it should feel. I have ridden these fins in similar boards (this tail is a little wider than normal)
The problems are
-
it’s stiff a little stiff in the kind of waves where I want a snappy bottom turn and snappy top turn.
-
It’s a little bit slidy.
Therefore, I was thinking that if I put in fins that sat way further back on the fin tabs, but were smaller and swept. I might gain control but keep the responsiveness.
“Have you ever had a board where on the take off, you always seemed to jump up and end up too far forward?”
this is how I can feel with this board quite often actually and that maybe why it feels a bit sluggish off the bottom. but I’ve seen pics and my stance looks correct (on tailpad placement as well) The board is definitely not too long for me.
I have on a few occasions forced myself to stand further back and I do get more pivot, but it feels harder to hold down a good carve longer (it’s harder to keep pushing and it’s always a little nervous going through the carve. I also lost a little of the front foot sweet spot of the board.
I was hoping that putting in 3 smaller fins that weren’t as upright and were closer to the tail might solve some of this.
Hey Tom -
Considering everything being the same - board, fins, wave, rider, etc.
Didn’t you say moving the side fin(s) forward would engage the rail more?
I think I got that from you, and thus have done that, with, what I feel is, success.
On my “toe side”/front side rail - I ride with the side fin further forward, and when I started doing this, esp. in bigger waves, I felt the bottom turns were much smoother and sure.
Subsequently - I think you also said side fin(s) further back turn more from tail - and going with this, and my experience would agree, I ride with my “heel”/back side rail fin further back and I like the snappier turns that way.
Anyway - just trying to see if my thoughts are correct with what I think I remember you saying.
Hope this makes sense.
I’m sorry man!
Bad day!
an don’t make me pull mah gat,
sho 'nuff!
Seems you need some help
TaylorO,
When you have an adjustable fin box like LokBox, Probox, Red X or 4-Way as you move the fins forward in the box because there is toe in and rail curve the leading edge of the fin moves away from the rail. Consequently, as long as you can keep your side fin engaged, your rail is going to pulled down deeper than if it was closer to the rail. That's what I was refering to about more rail engagement.
Now if you were talking about the initial layout of the board glass ons or fin system, positioning the side fins further forward or the side boxes further forward you may choose to have your leading edge further away from the rail or not. So, since an adjustable fin system was not discussed at the beginning of the thread, I did not factor that in to my response.
But, usually if I'm adjusting fins in a fin system I'll focus more on the spread of the fins fore & aft. A wider spread will provide more drive and stiffen the feel. A narrower spread will will loosen the board up. Same thing with rake of the fins. A rakier fin effectively widens the spread. A more up right fin will loosen things up.
Your assymetrical approach to setting your side fins sounds like it works well for you. But, I usually advise people to start tweaking their back fin/s first and then move to adjusting their side fins if they want more in a given direction. I have a lot of people that think tweaking their side fins is TABOO. "Only experienced shapers should go there".
Try the AM 7 line of fins (Assuming FCS since you mentioned the K fins.). I’ve tried the K fins and found that if I want a little more drive the FG7 work well, and if I want a lot I like the occy.
“I have on a few occasions forced myself to stand further back and I do get more pivot, but it feels harder to hold down a good carve longer (it’s harder to keep pushing and it’s always a little nervous going through the carve. I also lost a little of the front foot sweet spot of the board.” My tip for the nervous feeling is to totally commit to the turn, and put it as hard on the rail as you can. Bend your knees and drag your hand to pivot around. The best turn is the one where you have that “NO STOPPING ME NOW!!!” feeling.
Isss Allll Gooood d;-)
Quote:
Try the AM 7 line of fins (Assuming FCS since you mentioned the K fins.). I’ve tried the K fins and found that if I want a little more drive the FG7 work well, and if I want a lot I like the occy.
“I have on a few occasions forced myself to stand further back and I do get more pivot, but it feels harder to hold down a good carve longer (it’s harder to keep pushing and it’s always a little nervous going through the carve. I also lost a little of the front foot sweet spot of the board.” My tip for the nervous feeling is to totally commit to the turn, and put it as hard on the rail as you can. Bend your knees and drag your hand to pivot around. The best turn is the one where you have that “NO STOPPING ME NOW!!!” feeling.