Hi

I'm hoping someone can help me with this.

I've just bought a Formula board which has a deep tuttle box. This is a replacement box from the factory fitted one to reinforce for foiling.

I want to use the board initially for sailing with a fin, but all 3 deep tuttle fins I have won't seat. They are several mm proud of the board surface.

Measuring the box it looks like the box is around 6mm shallower at the front end than the fin head at the front end.

My question is - is it ok to grind 6mm off the fin head to make it seat correctly? Will this ruin the fin, especially in terms of shortening the bolt hole etc.

Anyone have experience of this? ??

One possibility is that replacement box installed could be "Surf Tuttle, but hopefully not because not only are too shallow for a deep Tuttle fin but also the fin screw holes ever so slightly different in position and angle
I had this same issue with a self install carbon GoFoil deep tuttle box, these are for sup and surf (Not windsurf)
Best of luck, do some research on what was fitted to your board
NB
Some foil masts used in windsurfing foils can be fitted with surf box tuttle (i have one)

Thank you. I'm tracking down the guy who put the box in so I might be able to check that.

This may or may not apply

Wow Paducah, that was enlightening! Thank you.

Thankyou for that - I also have no idea somebody had (inexplicably) made an in between size.
I will check my DT boxes I bought to make sure I don't inadvertently use one that's a "medium" and restrict the choices of what will fit. At least true DT can take everything else....

Still shaking my head about why they would think a new in between thing was even needed....

Could it have been installed backwards?

You sure you dont just need to sand the sides? Ive had at least 3 tuttle fin heads that were more than 6mm proud when installed new. I had to sand the sides quite alot but eventually fitted nicely.

Grantmac - it's actually the same depth front to back, but has the same tapered sides as a deep tuttle.

Olskool - the depth of the box is 6mm less than the height of the fin head a the front so it's hitting the top of the box. I'm sure the sides would also need some adjustment as the tolerances of manufacture won't be that precise, but it'll never seat any further in until the length of the fin head is shortened.

Starting to wonder whether it is a medium 'deep' tuttle box as mentioned in the video above.

My plan is to butcher the oldest fin and see how it goes.

Surf tuttle is equal both sides,
If the box is surf cutting down the fin will allow it to fit BUT the fin fixing screws will not work as the holes are in different positions and different angles
images of surf box and surf box with windsurf deep tuttle placed on top

I thought life was meant to get simper, wht purposely make it more complicated????
Unless it's to force you to buy more gear, or am I being to cynical?

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decrepit said..
I thought life was meant to get simper, wht purposely make it more complicated????
Unless it's to force you to buy more gear, or am I being to cynical?

Your not being cynical , thats exactly why they do it .

Tonyk - thank you.... that's a great illustration. The box in the board is 60mm deep front to back which completely tallies with the shape and dimensions of the surf tuttle you show.

I wonder if the surf tuttle is the 'medium' size box he mentions in the video above?

What a shame the manufacturers have done this without at least making things clear. I bet most people are only aware of tuttle and deep tuttle, especially as they are branded as deep tuttle when in fact they are this intermediate size!

Surf Tuttle is same depth front and back, medium tulle mentioned is deeper at the back. Medium Tuttle has bolts in same place and Surf turtles aren't.

at least that's how I understand it.

got to love standards

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OllyD said..
Tonyk - thank you.... that's a great illustration. The box in the board is 60mm deep front to back which completely tallies with the shape and dimensions of the surf tuttle you show.

I wonder if the surf tuttle is the 'medium' size box he mentions in the video above?

What a shame the manufacturers have done this without at least making things clear. I bet most people are only aware of tuttle and deep tuttle, especially as they are branded as deep tuttle when in fact they are this intermediate size!

Ok that's a surf box installed into your board
No point triming down a deep tuttle fin, the screws will not work anyway

As far as foils go, what i can tell you is aluminium masts on Neil Pryde flight AL 2019 & 2020 and Neil Pryde Glide Wind 2018, 2019 and 2020 can all be provided with a surf Tuttle head that suits you board
Other brands may also but i only know about NP
The Neil pryde mast head is interchangeable so later if you go to a different board with deep Tuttle / powerbox / track mount you can just buy the replacement head only
This is what happened to me, i unknowingly installed a darn Gofoil surf tuttle. Lucky for me I was able to use the Neil pryde surf tuttle head so I can still use the board
Since then I've changed boards and changed the head to deep Tuttle.

Jesus what a cluster f**K. Just like beta max vs VHS all over again.

One more point. Since it is a formula board, the deep tuttle box should go all the way up to the top skin, with no roof inside the box. This way, all tuttle fittings will work, be they regular, middle, or deep. I know a few board builders who are crazy insistent on this.

I have had formula boards modified for foiling, and have gotten a custom foil board with deep tuttle. In all those cases the roof of the deep tuttle box, BY DESIGN, is the underside of the top skin of the board. Reinforced, of course, so that the fender washers on top ride on the skin.

Of course, the screw locations have to be compatible.

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musorianin said..
Jesus what a cluster f**K. Just like beta max vs VHS all over again.

Just like mast bends all over again.

After spending the last week removing an old fin box from my formula board and replacing it with a Go Foil Deep Tuttle Foil Box. I am a little distressed reading this thread and wondering if I have completely wasted my time and made my board useless.

The foil mast is rock solid in the box however it sits about 10mm higher than it should be.

So my question is, will it work?

Will the loads be too much given that the full mast head is not supported. (70mm of the 80mm head is supported)

I am pretty comfortable with the construction method of the new box. I laminated the hole with 3 layers of 200gm carbon which is tied to the underside of deck. Shaped the high density foam and glued it in place before laminating over the box with 2 x 200gms carbon. The bolts were out by 5mm but new holes were drilled into the reinforced deck. I use a 5mm G10 plate to distribute the load on the deck of the board.

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AUS299 said..
After spending the last week removing an old fin box from my formula board and replacing it with a Go Foil Deep Tuttle Foil Box. I am a little distressed reading this thread and wondering if I have completely wasted my time and made my board useless.

The foil mast is rock solid in the box however it sits about 10mm higher than it should be.

So my question is, will it work?

Will the loads be too much given that the full mast head is not supported. (70mm of the 80mm head is supported)

I am pretty comfortable with the construction method of the new box. I laminated the hole with 3 layers of 200gm carbon which is tied to the underside of deck. Shaped the high density foam and glued it in place before laminating over the box with 2 x 200gms carbon. The bolts were out by 5mm but new holes were drilled into the reinforced deck. I use a 5mm G10 plate to distribute the load on the deck of the board.

It's far far from ideal, i think you need to take board + foil and show some other experienced windfoilers in your area and get their opinion
It would be a horrible shame to lose that lovely F4 foil

If the finbox has the name "tuttle" attached to it, it is required to comply with Tuttle's design. That said, there might be some wildcatters out there who are playing around with this and messing everything up.

Before you touch the foil with any sandpaper, Bruce Peterson insists you first REALLY work on getting it pushed down in there. He likes to use some sort of spray lubricant, such as McLube, to help things.

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AUS299 said..
After spending the last week removing an old fin box from my formula board and replacing it with a Go Foil Deep Tuttle Foil Box. I am a little distressed reading this thread and wondering if I have completely wasted my time and made my board useless.

The foil mast is rock solid in the box however it sits about 10mm higher than it should be.

So my question is, will it work?

Will the loads be too much given that the full mast head is not supported. (70mm of the 80mm head is supported)

I am pretty comfortable with the construction method of the new box. I laminated the hole with 3 layers of 200gm carbon which is tied to the underside of deck. Shaped the high density foam and glued it in place before laminating over the box with 2 x 200gms carbon. The bolts were out by 5mm but new holes were drilled into the reinforced deck. I use a 5mm G10 plate to distribute the load on the deck of the board.

To better understand the complete fit.

A couple of questions:
1. Are the tapers in the box in full contact.
2. Is the head of the mast bottoming out.
3. Is the head of the mast the same angle as the bottom of the box.
4. What is the G10 plate attached to.
5. Do you want to use the board for finning.
6. Do deep Tuttle fins fit the new box.

1. Are the tapers in the box in full contact. YES
2. Is the head of the mast bottoming out. NO
3. Is the head of the mast the same angle as the bottom of the box. YES
4. What is the G10 plate attached to. Sitting on top of the deck, used as a large washer to distribute load from bolts.
5. Do you want to use the board for finning. Foiling
6. Do deep Tuttle fins fit the new box. They sit proud by 10mm.

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AUS299 said..
1. Are the tapers in the box in full contact. YES
2. Is the head of the mast bottoming out. NO
3. Is the head of the mast the same angle as the bottom of the box. YES
4. What is the G10 plate attached to. Sitting on top of the deck, used as a large washer to distribute load from bolts.
5. Do you want to use the board for finning. Foiling
6. Do deep Tuttle fins fit the new box. They sit proud by 10mm.

As the tapers are in contact you have a good connection through the entire box.
As the head is not bottoming you are not relying on the bolts alone.
If foiling only then no worries that it's the wrong box apart from resale.

I would say you will be ok as you have a solid fit into the box & a good box install.

To get the other 10mm in you would have to change the tapers on the mast head & if you don't get them accurate the good connection will be lost.
Once the head bottoms out the tapers stop engaging and you then load up the bolts & point-load spots in the box.

If the head of the mast doesn't bottom out, you can also pour in an epoxy spacer to fill the void.

I have on old Formula board with very deep Tuttle box, the head of the mast tapered and fit perfectly flush with the board, but left a few cm gap at top of the box. I drilled another hole between the screw holes, fitted the mast and screwed in (with plastic straws around the screws), then filled with liquid epoxy and solid balls shaped out of knead-it. The mast now bottoms out, is tapered and fits flush, and more importantly, shows no signs of weakness - yet.

You don't want the head of the fin/foil to bottom out at the inside top of the box. What you want is solid contact on both tapers (and the parallel sides, of course) and that's it. There should be a gap at the inside top. This ensures taper contact. The screws are meant to hold the foil/fin tight to the tapers.

If you are getting solid contact in the tapers, and it is still proud of the board, either the box is not per tuttle design or the foil/fin top is not.

My bet would be that the box is wrong. Don't go sanding the very expensive foil/fin until you have determined this. Try to fit your foil/fin into other boards if you can. Use McLube.

Agreed it should not bottom out, it's a taper lock. No Tuttle or power box fin should ever bottom out- it jams into tapered sides.

tuttle and deep Tuttle have been a standard ie: engineering drawings etc
for soo long that if I bought a deep Tuttle box and it was shallower I'd demand a refund. That's crap if it's called deep Tuttle and it's 10mm shallower than 'real' deep tuttle
go foil or whoever can make a new size if they like but they can't call it deep Tuttle if it isn't ..... go
refund man

Plenty of cases of foilbox walls cracking, expanding or softening with use, and the mast jamming up into the gap, sometimes at a really bad angle (front up, rear down), also further damaging the back end of the box. With a 10.0 sail and race foil, the up forces into the box are far more extreme than a slalom or even formula fin. I'll take one that bottoms out any day.

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Mark _australia said..
Agreed it should not bottom out, it's a taper lock. No Tuttle or power box fin should ever bottom out- it jams into tapered sides.

tuttle and deep Tuttle have been a standard ie: engineering drawings etc
for soo long that if I bought a deep Tuttle box and it was shallower I'd demand a refund. That's crap if it's called deep Tuttle and it's 10mm shallower than 'real' deep tuttle
go foil or whoever can make a new size if they like but they can't call it deep Tuttle if it isn't ..... go
refund man

Bit of a piss off after all the work to install the box.
Too late for a refund

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Mark _australia said..
Agreed it should not bottom out, it's a taper lock. No Tuttle or power box fin should ever bottom out- it jams into tapered sides.

The people that actually build this stuff disagree. The top is tied into the deck and provides a wider area to spread the load rather than point loading the front of the box when the foil wants to rotate.

windsurf.star-board.com/products/foil-boards/ scroll down to "foil box"

"FOIL BOX
The Foil Box is larger and stronger than a normal fin box to distribute loads over a larger area. It is built using solid sheets of 20 mm thick high-density PVC with 8 mm thick carbon fibre walls, and has a flat, parallel bottom which allows the box to take both types of foil bases: tapered 'Tuttle-style' base and rectangular foil bases. In either case, it is strongly recommended for the front of the foil's base to reach the bottom of the box. This ensures that the vertical lifting load from the foil will be carried by both the front wall of the box and the bottom wall of the box."

Several shops sell shims to fill the gap between the box and tuttle head if one exists to either alter or fix the rake of the foil mast
Example: marseille.glissattitude.com/blog/reglages-windfoil-le-rake.html

Translation via google: Note. We recommend this setting solution without reserve on the floats dedicated to the foil, and which are fitted with reinforced boxes. Whether it is Flika or Cobra, we have experienced this solution for months in no structural problem. On the other hand, we have no hindsight concerning the use of a support at the bottom of the case on old slalom float cases.

Sidenote: Gutted for AUS 808 Too bad when they went off and made their own standard they didn't make it absolutely clear.