Hi wanted to throw the question out there,
How stiff is the hydrofoil front blade to the keel and the keel to the board?
I am just thinking that there has to be flex in both and not totally ridged.
Its a pity that no shops in wa sells them.
Thought I would make my own, which I have still to try him out.
Even out of ally it would still have flex?
Cheers
Hey mate you don't want any 'play' or movement in the attachment of the foils to the fuselage/mast or the mast to the board. In terms of flex the stiffer the better all around I would say. I have a Taaroa Sword and a home-build and comparing them the Sword is super stiff. The foils don't flex at all and the mast has very little flex. The front foil is attached to the fuselage with 3 bolts and doesn't budge a bit and it is attached with a plate to the board with 4 bolts which can't have any play in it.
The home-build on the other hand is made with fiberglass/epoxy resin and plywood and has quite a bit of flex. The foils are glassed on permanently and I used a plate mount so no movement there but there is quite a bit of flex in the mast. Upwind the flex doesn't make too much of a difference but downwind the flex makes it quite hard to go deep and fast (it has almost a skatey snowboard carve feel to it going down wind, fun but not fast!)
If you are going to make one I alloy could be a good option if you can get your hands on it, but ultimately carbon would be the best option for weight and stiffness (but very $$$). Glass and plywood worked great tho. Stick with a plate attachment which is the best option. A tuttle box is a lot more work and whilst you save a little on drag when taking off (if the boards in the water your going slow anyway 
) there is a lot of force on the board/box and surely a bit of play in the box if you take it in and out quite a bit.
The big names in the market are Sword and Spotz at the moment and if you bought one of them you would have no issues :D Lots of new brands coming on to the market with big brands rumoured to start making them too, time will tell. Go ahead and make one though lots of fun and a cheap option to learn on (my build was around $250-$300). Foiling is such a cool feeling...say goodbye to chop!
I would agree with doycle that in term of flex: the stiffer the better.
You want the mast to be super stiff, but you also want the bottom "tail" to be quite stiff in the longitunal axis, otherwise while you'll be pushing on your foil upwind while the main mast will twist with the bottom part...and be quite inefficient...
The stiffness will also play on the longevity of your foil, the stiffer the less your foil will be prone to delam' or breakage over time.
However, in my opinion, a tuttle head such as the one on the SPOTZ (and now AGUERA foils & KFA as well) is a much better option than a plate like on the SWORD to avoid any play on the board-foil attachment over time, and is also a much easier way to pack & travel with :0)
We are a growing fleet of foil riders in Perth, most of us riding SPOTZ foils (Dale S, Jonno K, Pete M, Allan, and myself), and it would be great to see more kite-foilers! So smooth, quiet & fun to ride :0)
Haha I guess time till tell which attachment method is the best, my raceboard fins in a tuttle box need tuning to keep them snug/tight from taking them in and out. It's interesting that Taaroa Sword and the new Carafino and Zeeko foils have the plate. They both have their advantages and disadvantages I guess.
In terms of a home build the plate is a no brainer, much easier to make and very difficult to break. I've seen a DIY tuttle box and a professionally installed tuttle box fail/break with a foil. The tuttle head could be a good option if you were going to eventually get a Spotz, Ageura or KFA in the future but i'm sure they all have different sized tuttle/deep tuttle boxes and heads...
All foils will have some amount of flex regardless. Similar to the raceboard fins there is different/ good flex patterns.
Carbon is def the stiffest method to achieve the least flex but also manufacturing technique and designs play a big role.
KFA (Kitefoil Australia made in Melbourne) uses Autoclave to achieve very stiff and light foils. Others use foam in their foils...
Generally the less side and torsion flex you get the better it is when having lots of load on the foil.
I think tuttle is the way forward because the head sits flush in the board so no drag when board touches water plus it is stronger than the plates.
Select to expand quotedoycle said..
Haha I guess time till tell which attachment method is the best, my raceboard fins in a tuttle box need tuning to keep them snug/tight from taking them in and out. It's interesting that Taaroa Sword and the new Carafino and Zeeko foils have the plate. They both have their advantages and disadvantages I guess.
Yah I think the plate is a stronger method due the the larger surface area of the actual mounting on the board and in theory should last a long time.
Recessing the plate into the board would eliminate the drag issue (which inst a problem 99% of the time on a foil anyway).
In normal use a tuttle box mounted fin has lots of sideways force put on it from the pressure generated by the water hitting the fin, but it doesn't usually have much force put on it in the other directions unless you hit something on the leading edge while going forward, and as we all know the bolts occasionally need tightening and the fins needs shims to make it tight from time to time.
The tuttle box although has been used in many forms of windsurfing and kiting over the years I dont think it has ever been used in such a way with somebodies weight directly on the board without any support from water, and the foil is mounted right down the back so all this weight it put on the thinner ends of the tuttle box, if it bottoms out in the box and pulls up tight is also probly a better option and would offer more support.
Only time will tell if this new use for a tuttle box last for the life time of the board.
Keep an eye on the guys that are throwing in high jumps and stuff, this would add more force to the mount and test it out, if these handle it then all is good.
