Questions on Fins

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Graham_U
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Questions on Fins

Post by Graham_U » Fri Jan 28, 2005 12:21

My new board has a 40 cm. Deep Tuttle Box. Must admit on first fitting I actually found the trimbox on my old Techno quicker and easier to use, and more flexible. But I know Trimbox is seen as old and out of favour now. Any care to enlighten me on the pros and cons of fin development.

I've seen the term Tuttle and Deep Tuttle used, are these the same thing, is one a deeper hole in the board?

If different can a normal Tuttle fin will fit in a Deep Tuttle box?

This is all new to me, and the sort of thing that people assume you know.
Graham

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Post by kelvin » Sun Jan 30, 2005 07:55

Fin Systems
Explaining the difference between the Powerbox, Trimbox, Classic box and Tuttle box fin systems used nowadays.
- - - - - - - - - - -

There are 4 major fin box/slot configurations currently in production. The type of fin box used is often a function of the intended use the designer has for a particular board.

The 4 basic configurations are:

* Tuttle Box (both Std. depth and "Deep Tuttle")
* Power Box
* Trim Box (often referred to as a Power Trim box)
* Chinook Slot (referred to as an "A" box if it's design depth is 2.5 cm or approx. 1" and as an "E" box (for European) if it's design depth is 3 cm or approx. 1.25".

The Tuttle box has straight sides and the root is a uniform 1.60 cm (.625") and the "fit" is supposed to be quite tight on the sides. The depth is set by the angles on the front and rear of the fin root. If your fin will not go all the way into the box until the root of the fin is even with the bottom surface of the board or finbox, then you need to file or sand the radius's on the front and rear of the fin to allow it to go further into the box. You do not want to alter the width or "thickness" of the root unless you are sure it's oversize. The fin gets most of it's support from the close fit between the sides of the fin root and the sides of the fin cavity in the board.

The "Deep Tuttle" configuration is the same width on the sides, but the fin root is much taller (deeper), measuring 7 cm (approx. 2 3/4") at the same point on the root that your std. Tuttle measures 5 cm.

The front and rear angles and radius are the same for the std. and deep Tuttle, the major difference being the extra 2 cm of root "height".

The Powerbox is a system using a root with both tapered sides and tapered front and back. It's most commonly found on mid size boards from F2 and Mistral. On the wider race boards, both of these manufacturers have adopted the stronger Tuttle or Deep Tuttle system.

The Trim box, was designed by Bic and features straight sides, and the ability to move the fin forward and aft in the fin box, by sliding some plastic spacers to be either in front of the fin, some in front, some behind, or all of the spacers behind the fin. It's a pretty strong finbox, but even Bic uses Deep Tuttle boxes in their wide race boards.

Smaller wave and Bump and Jump style boards often use an "A" box because they are much thinner in the area where the fin mounts, and they are designed to use small fins as they are for waves, jumping, and radical maneuvers where a big fin would only cause problems. These boards typically use fins < 30 cm (12") in span.

Slalom boards in the 90-130 liter range usually come with the std. depth Tuttle, the Powerbox or the Trim box as they are intended for use with fins in the 28-48 cm range.

Both the Powerbox and the Trimbox are strong enough to handle fins up to about 50-52 cm. Beyond that, and you need a Tuttle box for really good fin/finbox integrity.

The Std. Tuttle Box can handle fins up to about 58 cm with good results, but for racing use and larger span fins (i.e. > 58 cm) the Deep Tuttle is the way to go. But these boards are usually very wide and quite thick in the finbox area to accommodate the deeper fin root.

Are they interchangeable?
Std. Tuttle fin roots fit nicely in deep Tuttle cavities if you can find screws long enough to secure the fin. The inserts in the Std. Tuttle root will be 3/4" further away from the top surface of the board. Deep Tuttle fins WILL NOT fit in std. Tuttle boxes, for the obvious reason that the root would stick up out of the bottom of the board at least 2 cm (3/4").

But there are down sides of putting a standard tuttle into a deep tuttle box.

1) The long screws transfer the load to the screw heads and even with thick rubber washers they can/do/have cracked the deck above the box.

2) These long screws can pull the std Tuttle up into the box causing the box to overflex and crack the board and box.

3) Assuming you don't over tighten the fin and cracking either the box or the deck. We also experienced deflection in the screws. Causing them to bend in the unsupported area. Making removing the fin impossible (as well as retightening).

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Graham_U
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Post by Graham_U » Mon Jan 31, 2005 17:57

Many thanks, that helps a lot. I won't try to put a standard Tutle in my BicT2 then.

Is it just fashion, or was there a real reason why Bic have moved a way from the trimbox. Seem so much quicker to fit that the deep tuttle.
Graham

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MartinF
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Post by MartinF » Mon Jan 31, 2005 22:26

Graham_U wrote:Is it just fashion, or was there a real reason why Bic have moved a way from the trimbox. Seem so much quicker to fit that the deep tuttle.
It's more akin to the VHS/Betamax wars of the 80's. The company with the best marketing beat the company with the best technical product.

BiC, Tiga (for a while, as they're owned by BiC) and Fanatic all used to use Trimboxes. As this was a considerable percentage of the marketplace, it stood up well to the less flexible, but (arguable) stronger and less expensive Powerbox.

Then Mistral bought Fanatic, so bye bye Trimbox, hello Powerbox.

So now, only BiC use Trimbox. Also, since the advent of gurt big fat-arsed boards and gargantuan fins, the Trimbox isn't man enough for the job. enter Tuttle & deep Tuttle. Less flexible again, but far stronger & able to support those 80cm fins on 1m wide Formula boards. Classic box was always used on wave boards - crap though it is. Freeride boards are getting wider, thuse necessitating longer fins & stronger finboxes, leaving the Trimbox just on the remaining smaller freeride boards.
It's an ill wind that never blows at all.

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Post by steve powell » Tue Feb 01, 2005 22:50

A quick word from the (mostly) silent majority which would like all fin mountings to be the same. I know life doesnt work like that but if they were all the same we could all have a good range of sizes instead of maybe 2 boards and 3 fins!

Steve
I will learn to carve! (and jump)

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fins bloody fins

Post by Brian D » Wed Feb 02, 2005 22:11

I thought I was over it - the coucellors told me the worst was over, then the fin dialogue in this formum brought it all back :cry:

- first ther were:-
- the technical explanations :roll:
- then the planning - a quivver of fins of the same type in incremental sizes :roll:
- then the purchasing, swapping & horse trading 8)
- to end up after several years of effort with seven trimbox fins in 2 cm increments.
And what happens - Fanatic Change over to powerbox.
I end up with three boards - one with a tuttle, one with a clasic and one with a powerbox. - ooh and of course seven trimox fins - all of which totaly useless for the current boards. :cry:
Oh yes and of course I also bought a betamax vidio player as well.
swaps anyone ??.

mother always told me it was a mistake to think too much!! :idea:
Cheers
Brian

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MartinF
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Post by MartinF » Thu Feb 03, 2005 09:33

Brian - if you've got all this old kit that you don't want/can't use, why isn't it up for sale :?:
It's an ill wind that never blows at all.

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