Today was out in 20-50 kph on-shore winds...
Tested the winds with the old Mistral Equipe II XR carbon and the North Sails Duke 6.9.
No dagger needed , especially since I just repaired the gasket...

Was having a blast and just when I was considering going to a slalom board with deep tuttle box, I hit a BIG rock with my fin.
Heard a BANG and spun out completely and went in the shallow water ...
Knew it was fin gone, which i confirmed ...

Since it was a power box/PB, the fin broke OFF completely and there was NO damage to the fin nor the board ...
Was around the time to leave and so I did after checking everything out ...

Was thinking to myself, if I had been sailing with a tuttle/deep tuttle, would it have ripped out the box , or just catapaulted ?
Either way, there would have been damage to the board ....
The last time this happened to me, it was with a US / Euro box and the rock incident resulted in damage to the nose....

So, does this mean , for such a calamity, the power box is our best option ??

There are probably a 100 different ways to bust a fin or a fin box, your single example I would consider non-conclusive.
Speed, angle of collision, box installation, fin material, way too many variables.

The fin bolts are designed to strip out first, to protect the box.
Usually that happens.
You will notice the barrel nuts in fins are much looser than a normal nut.

^^^ yep. I've lost powerbox fins in the past and come home with the bolt still in the board.

I prefer to lose the fin rather than damage the board (though getting back in can be a struggle)

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joe windsurf said..
I hit a BIG rock with my fin.
Heard a BANG
Knew it was fin gone,

there was NO damage to the fin

no damage at all ? You're lucky !!!

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Shifu said..
^^^ yep. I've lost powerbox fins in the past and come home with the bolt still in the board.

I prefer to lose the fin rather than damage the board (though getting back in can be a struggle)

At least your car would smell better on the way home.

^^^^ gold !!!!!

yeah - no damage to fin BOX - fin was gone
and so the smell was gone too

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Sparky said...

Shifu said..
^^^ yep. I've lost powerbox fins in the past and come home with the bolt still in the board.

I prefer to lose the fin rather than damage the board (though getting back in can be a struggle)

At least your car would smell better on the way home.

That's the silver lining right there. Good old power box.

The Tuttle deep or not , IMO. Would be the strongest . Having 2 bolts and a large base. Requires a thick tail .

FWIW

tuttle
powerbox
trim
USBox

for multi use
mini tuttle
USBox
slot box

the surf fin boxes for side bites or...
ProBox
Futures

FCS.. only single units not the series 1
of course opinions will vary, installation and the box itself are all variables, not all slot boxes are created equal.


I know some Australian units are made, saw them on surfinggreen.

The variances in the Tuttle boxes that come on boards out of the Cobra factory are what annoys me the most. Over the last 6 boards I have had not one has been made to the Tuttle specs and has needed work to make fins that were on spec fit.

^^^^^^ MrFish has been tuning Shifus fins?

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MrFish said..
The variances in the Tuttle boxes that come on boards out of the Cobra factory are what annoys me the most. Over the last 6 boards I have had not one has been made to the Tuttle specs and has needed work to make fins that were on spec fit.

I find this the case with many fin boxes.
It's annoying when the box and fin both come from Cobra. Tutte being the hardest to fit.

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Sparky said..
^^^^^^ MrFish has been tuning Shifus fins?

I'm assuming Shifus is an acronym for something ?

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MrFish said..

Sparky said..
^^^^^^ MrFish has been tuning Shifus fins?

I'm assuming Shifus is an acronym for something ?

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MrFish said..
The variances in the Tuttle boxes that come on boards out of the Cobra factory are what annoys me the most. Over the last 6 boards I have had not one has been made to the Tuttle specs and has needed work to make fins that were on spec fit.

What are these "Tuttle Specs" you speak of?

I have copies of the original Larry Tuttle drawings and they are Wrong, so where do we begin?

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AUS 808 said..

MrFish said..
The variances in the Tuttle boxes that come on boards out of the Cobra factory are what annoys me the most. Over the last 6 boards I have had not one has been made to the Tuttle specs and has needed work to make fins that were on spec fit.

What are these "Tuttle Specs" you speak of?

I have copies of the original Larry Tuttle drawings and they are Wrong, so where do we begin?

If they are the original Larry Tuttle drawings how can they be wrong !

I have been told by a couple of sources that when Cobra was originally set up that they had the wrong dimensions or sample and that caused issues from the outset.

The width of the box is usually the biggest issue. I have had a number of fin manufacturers confirm that Larry Tuttles original design had the width at 15.75mm and that is what I base my measurements around. I have had boards with boxes from 15.6 to 16.0mm wide which is a huge variance on something that requires a fit between parallel sides. This is where power box comes into its own with the tapered sides and ends.

Have a look in the QLD section to see how Jeff has tested this theory. It's a trade off between the strength of the connection to the board and the lack of damage to the board when you hit something. Which is cheaper/easier to rectify, a lost fin or a broken board? Surely PB has to be the winner for most general purpose sailing. So you hit a rock, you spit the dummy over losing a fin, get another one out the back of the car and keep sailing or you spit the dummy over breaking your board, pack up and go home sulking. Both ways cost money, but only one way keeps you sailing.

I still like having adjustability, fin distance to the tail, for a single or a tri. I wish PB or Tuttle would come up with a way to have an adjustable fin, the insert base remains fixed in the box, but the fin part can be moved forward or back, sliding along the base somehow, then locked in.
Because of that, I still prefer the US box.
Only need about 7cm (2 3/4") max of adjustability, maybe some year, in a land far far away.

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If they are the original Larry Tuttle drawings how can they be wrong !

Exactly, that is my point but I can assure you they are wrong.
Either a dimension or an angle are wrong.
Obviously Larry didn't have CAD

Powerbox fins need fitting too. I have always had to do some fooling about with sandpaper and files. Especially so in recent boards the boxes of which are a little tight. I think there are variations in boxes and fin heads.

I really haven't had a lot of problems with Tuttle fins, sure you need to sand new fins to fit the board, but at least you can get a nice tight fit. Boards have been, iSonic, Futura and Patrik Slalom.