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attaching hydrofoil to twin tip and a foam directional

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fun2kite
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attaching hydrofoil to twin tip and a foam directional

Postby fun2kite » Tue Mar 11, 2014 6:24 am

Hi All,

Brand new to foliling. Just bought one from Moses. I hope to get some advise on how to attach it to the existing boards I have. thank you very much in advance for your help and time.

Questions:

1. Twin-tip:

a.
How to figure out where exactly on a twintip attach the foil? I have seen on directional boards, foil typically attach right at the end of the back foot strap. But twintip maybe different. Is there any rules on figuring it out?

b.
Will just drilling holes thru the twintip to screw in foil work? Or will my twintip break in a water after I drill 4 holes in it to attach a foil. (I have Cabrinha Custom 133 cm to sacrifice for this experiment)

Or should I be glueing some kind of a plate to the bottom of the board and then drilling in that plate? If there are any posts detailing the procedure of attaching to a twintip please point me there.

c.
Is ridding foil with a twintip recommended at all? to my understanding, it should not make a difference since once up out of the water, I would be ridding on a foil and just stand on a board.
Does it make a difference to which type of board foil is attached?
I would imagine, getting initial speed, maybe more difficult with a twintip as it has less surface and I plan to use foil in winds of 5-9 knots. is using twintip detrimental as far as getting out of the water in low winds or it does not matter?

2. Directional Foam based board. (Airrush Monaro 2009 )

I was told I need to re-enforce the board to be able to attach a foil to it.

Please help me with advise and maybe instructions on how to actually re-enforce the board?

And what are my options for attaching to the foam board? (Do I need to glue in some plate? should it be cut INTO the board? or attached at the bottom of the board (sticking out)
What materials I will need to re-enforce it? and how to actually do it?

Really appreciate everybody's time.

thank you!

-D.
Attachments
air-rush22.jpg
air-rush11.jpg

Bradn
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Re: attaching hydrofoil to twin tip and a foam directional

Postby Bradn » Tue Mar 11, 2014 7:00 am

I would say the airrushboard, since it looks to have a few positions to move the foot straps?
as for position, correct me if I'm wrong, but in between the footstraps maybe the centre of the main wing could work?

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Re: attaching hydrofoil to twin tip and a foam directional

Postby lodwik » Tue Mar 11, 2014 5:17 pm

I just did this to one of my Directionals , Since I no longer ride anything but the foil
The biggest problem is where to mount the foil relative to the foot straps .
the centre of lift varies dramatically with the foil manufacturers
The best is to get he position relative to the foot straps from someone riding one already or the manufacturer . :evil:
once you know where ,
remove the deck pad for an area 8 inch by 10 inch
get 1/2 inch pvc tubing , drill the front holes from the bottom & rear holes from the top
remove around 1/4 inch of extra foam where you will place the tubes
fill the hole with epoxy , then insert the tub so it also fills with epoxy .
roughen up the top & bottom surfaces around 10 by 8
apply 2 layers or glass & Epox to the top & them the bottom
once hardened drill your hole
I just used regular bolts with Large washers on the Deck & then cut the bolts to length on the foil side with self locking nuts , Stainless . :thumb:
If you can get nut inserts that you can mount on the deck side is even better :) .

fun2kite
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Re: attaching hydrofoil to twin tip and a foam directional

Postby fun2kite » Thu Mar 13, 2014 4:42 am

Thank you for your advice. Sounds like this is quite a big job.
Can I ask a few more questions?

1. Why drill front from bottom and back from top? I am sure there is a reason.

2. roughen up the top & bottom surfaces around 10 by 8
apply 2 layers or glass & Epox to the top & them the bottom :

When we do that, do we wind up with things sticking out on top and bottom of the board?
If we apply two layers of glass and epoxy on top of the surface of the board? Or do we need to cut into the board and then when we apply those layers we will wind up with the same surface as before?

Also what does these two layers accomplish, they will actually prevent the foil from caving into the board?

Do we need both glass and epoxy or just two layers or either one?

Nut inserts: is it better to have inserts at the top or bottom of the board?
I guess top as otherwise, you would have bolts sticking up on the top desk and you may need to stand on them?


If I were to use a twintip instead: Are there any disadvantages of using twintip vs directional board with a foil? is it harder to get going in light wind? And do twin tips also need re-enforcement or you can just drill thru them and not worry about all other stuff that needs to be done for directional boards?

Thank you again for your valuable tips!!

-D.

lodwik wrote:I just did this to one of my Directionals , Since I no longer ride anything but the foil
The biggest problem is where to mount the foil relative to the foot straps .
the centre of lift varies dramatically with the foil manufacturers
The best is to get he position relative to the foot straps from someone riding one already or the manufacturer . :evil:
once you know where ,
remove the deck pad for an area 8 inch by 10 inch
get 1/2 inch pvc tubing , drill the front holes from the bottom & rear holes from the top
remove around 1/4 inch of extra foam where you will place the tubes
fill the hole with epoxy , then insert the tub so it also fills with epoxy .
roughen up the top & bottom surfaces around 10 by 8
apply 2 layers or glass & Epox to the top & them the bottom
once hardened drill your hole
I just used regular bolts with Large washers on the Deck & then cut the bolts to length on the foil side with self locking nuts , Stainless . :thumb:
If you can get nut inserts that you can mount on the deck side is even better :) .

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Re: attaching hydrofoil to twin tip and a foam directional

Postby Peter_Frank » Thu Mar 13, 2014 10:43 am

fun2kite wrote:Hi All,

Brand new to foliling. Just bought one from Moses. I hope to get some advise on how to attach it to the existing boards I have. thank you very much in advance for your help and time.

Questions:

1. Twin-tip:

a.
How to figure out where exactly on a twintip attach the foil? I have seen on directional boards, foil typically attach right at the end of the back foot strap. But twintip maybe different. Is there any rules on figuring it out?

b.
Will just drilling holes thru the twintip to screw in foil work? Or will my twintip break in a water after I drill 4 holes in it to attach a foil. (I have Cabrinha Custom 133 cm to sacrifice for this experiment)

Or should I be glueing some kind of a plate to the bottom of the board and then drilling in that plate? If there are any posts detailing the procedure of attaching to a twintip please point me there.

c.
Is ridding foil with a twintip recommended at all? to my understanding, it should not make a difference since once up out of the water, I would be ridding on a foil and just stand on a board.
Does it make a difference to which type of board foil is attached?
I would imagine, getting initial speed, maybe more difficult with a twintip as it has less surface and I plan to use foil in winds of 5-9 knots. is using twintip detrimental as far as getting out of the water in low winds or it does not matter?

2. Directional Foam based board. (Airrush Monaro 2009 )

I was told I need to re-enforce the board to be able to attach a foil to it.

Please help me with advise and maybe instructions on how to actually re-enforce the board?

And what are my options for attaching to the foam board? (Do I need to glue in some plate? should it be cut INTO the board? or attached at the bottom of the board (sticking out)
What materials I will need to re-enforce it? and how to actually do it?

Really appreciate everybody's time.

thank you!

-D.


Hi

I can see you have never done any fibreglass jobs yourself.

Would advice that you get someone to build the Monaro attatchment setup for you (or even better, WITH you, so you can learn) :thumb:

You need to get some basic experience with materials and construction - and this is not as easy as it sounds, and will take time and experience.
Of course you have to use full through bolts from bottom to top, and reinforce on top of that - otherwise your board will be destroyed and bend or even break the foil off at very first journey.

With the TT I think you might be able to pull it off, just by mounting directly through - and a good construction should not soak water IMO.

Regarding its position, it fully depends on the actual foil, and can be extremely different from brand to brand.
The only thing you can do when new, is to make it as "the brands own position" for the given foil - or even better, buy a board from MHL, and you can experiment yourself later, with your own boards :naughty:
This way you KNOW the gear is OK, and it is you who need to practice more (good to know, eventhough you dont have an excuse when it wont work ha haa)

Bolts and screw heads can stick out, depending on how it is made.
No problems with that on the lower part - even the carbon plate can "stick out" (well, it will give a unnoticeable bit more drag before foiling, but no problem for you at all), apart from on the topside, where you need to hinder your feet getting "torn" somehow, if it is not countersunk/sunk into the surface.


Are you planning on going strapless on your TT ?
As straps is IMO not good, when you dont "jibe" and change sides...
I would not start out on the TT, not with straps, nor strapless - WAY too difficult when new.

You need a big board to keep you floating, while you learn to balance things.

Are you an experienced raceboard rider ? (really big board and fins that is ?)
If so, you will find the change to a non foiling foilboard possible.

If you are only used to waveboards and TTs and freeraceboards, you will absolutely hate the feeling at first - and you will fall nose over A LOT OF TIMES, as the foil acts as an anchor even more than the 45cm finned raceboards :o

Indeed YES, the bigger board will be an advantage in conditions "on the edge" at the lower limit.

But eventhough foiling is easy as eating pie, WHEN you can, it is not just something you step up on the board and do, or learn in a couple of sessions :(

On a beginner foil like the Carafino, it will come quite fast.
On a racefoil, you have to practice over and over for a looooong time - but this time is well spent, as when you CAN, it becomes easy one day :D

The MHL Lift is, as far as I can see, a foil somewhere in between, good for allround purposes.

But dont expect you to just go out and "ride away" :-?

Every single one who has learned, knows what I mean - and those who havent tried it yet, havent got a clue how it feels...
It is impossible to explain - you got to feel and try it yourself :rollgrin:


Hope you can use above.

8) Peter

fun2kite
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Re: attaching hydrofoil to twin tip and a foam directional

Postby fun2kite » Fri Mar 14, 2014 2:40 am

Peter,

Thank you very much for your very valuable advise and the time you took to write it.
It will be very helpful to me and any others who will look for this advise at later times.

I will indeed seek help to do this work since as you pointed out, I have never done it.


-D.

fun2kite
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Re: attaching hydrofoil to twin tip and a foam directional

Postby fun2kite » Sat Apr 12, 2014 4:40 pm

Thank you all for advise. This is the final result of my setup.

1. Four holes with aluminium tubing in each hole.
2. fibreglass re-enforced top with an aluminium plate on top of that to hold the foil.
3. since the aluminium tubing inserts go from the bottom of the board all the way thru to the top, there was no re-enforment done on the bottom of the board. As foil attach to the bottom with 4 screws all the pressure is transferred thru the inserts to the top plate.

Picture of the setup is attached.

-D.

1982180_10151971472822352_1093939751607257195_n.jpg

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Re: attaching hydrofoil to twin tip and a foam directional

Postby wdric » Sun Apr 13, 2014 12:02 am

Nice looking setup

In that picture am I seeing a slot in the board to adjust the foil position forward or back?

You mention no reinforcement in the bottom of board?
You should keep an eye on this incase it goes soft, the bottom is under a crush load (compression).

fun2kite
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Re: attaching hydrofoil to twin tip and a foam directional

Postby fun2kite » Sun Apr 13, 2014 8:04 am

No, the foil can't be adjusted. there are four holes in the board all the way thru and the bolts holding the foil go thru those wholes.

The holes in the board are lined with aluminium tubing which is cut to exact "thickness" of the board. So the idea is that even though there is no reinforcement on the bottom of the board, the foil should NOT create compression pressure on the bottom as it will be pressing against the metal tubes inserted into the wholes and those tubes are pushing against the aluminium metal plate on top of the board. Will that work or you still think I will have problems with the bottom of the board?


wdric wrote:Nice looking setup

In that picture am I seeing a slot in the board to adjust the foil position forward or back?

You mention no reinforcement in the bottom of board?
You should keep an eye on this incase it goes soft, the bottom is under a crush load (compression).

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Re: attaching hydrofoil to twin tip and a foam directional

Postby ronnie » Sun Apr 13, 2014 8:47 am

fun2kite wrote:No, the foil can't be adjusted. there are four holes in the board all the way thru and the bolts holding the foil go thru those wholes.

The holes in the board are lined with aluminium tubing which is cut to exact "thickness" of the board. So the idea is that even though there is no reinforcement on the bottom of the board, the foil should NOT create compression pressure on the bottom as it will be pressing against the metal tubes inserted into the wholes and those tubes are pushing against the aluminium metal plate on top of the board. Will that work or you still think I will have problems with the bottom of the board?


wdric wrote:Nice looking setup

In that picture am I seeing a slot in the board to adjust the foil position forward or back?

You mention no reinforcement in the bottom of board?
You should keep an eye on this incase it goes soft, the bottom is under a crush load (compression).


What you say is correct while there is no load on the foil/mast assembly. The compression from the bolts will be taken by the aluminium tubes.
Once leverage forces come into play, its going to be different. You could try levering the foil rearwards to see if you can feel any board skin movement at the rear edge of the top of the mast.
If the foil lifts 100kg and the lift/drag is about 10 to 1, and add the drag of the mast, maybe 15kg force rearward applied at the foil would simulate the minimum sort of forces you could expect.

So I suppose with the board upside down and someone putting their weight on the foil where the mast attaches while another person pushes rearward with bathroom scales until they read 15 kg would simulate it.

Board and foil look great when sitting there.


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