Need some advice on boards

[Denisesewa]

I received the two doner boards for for the two foils I'm building, they are 157 X 40 ( grey one) and 159 X 40 (Red one), the red one is directional and on the heavy side but has very little tail rocker, the grey one is twin tip and is a very light carbon build, since my friend donated the boards I feel like I want to set up the light one for him so....
how do I figure out where to mount the strut ? I will install front foot strap inserts after its been ridden and location determined, the plan is to only have a front foot strap/straps ( or maybe no straps).
Should I shorten the board to remove some of the tail rocker ? I'm kinda thinking the length will be a good thing considering how narrow these boards are and perhaps the tail rocker will make initial lift off easier?
These kite foil boards are to be used to have fun on and learn technique, speed is not what we are after. I know these boards are not ideal but its what we have and they will be used.
Any advice on strut placement, attitude ( angle) of board ect. will be greatly appreciated.

[Hawaiis]

Based on your photos, I would mount the strut right under where your rear foot strap would be. This is based on average weight.

[Denisesewa]

Based on your photos, I would mount the strut right under where your rear foot strap would be. This is based on average weight.

So disregarding footstrap location are you basing this on rocker or percentage of board in front and behind?, approximate center of lift?
I am trying to understand the reasoning for placement other than footstrap location ( which can be moved)
My initial thoughts are to keep the plane of the board parallel to the plane of the foil and have the center of lift centered between your feet, problem with this is how to determine center of lift other than to guess its about 1/3 chord of the front wing ( Center of lift on "most" aircraft is between 1/4 and 1/3 chord) as well as center of gravity being just ahead of lift, since you are being pulled by a kite and have the weight of the majority of the board out front it seems to me would push the CG back a bit ?
Anyway, the center of the present rear footstrap on this board is 20 inches which is 1/3 the length of the board. from pictures of factory foils I've seen strut location is all over the place as is strut angle and design but most seem to be between 1/4 and 1/3 board length.
On a different subject , why is it you are just about the only DIY foiler to post videos of your creations in action, seems most build threads just die of unknown causes.

[Hawaiis]

I guess everyone is too busy foiling. I am basing the location from experience. I had to guess where to mount the original Carafino on my 3 1/2 foot Paipo board. Every time I change the wings, the foot positions change. I guessed the location of the Alpine 4.5 and Spotz 2. They were all pretty spot on.

[Tone]

yeah I always thought the position was based on where the front foil actually sits and it's relation to the mast.

Sword seem to have the foil right at the back where as some of the lower aspect foils have them infront of the rear strap.

[ahmthai]

The strut attachment location will be based on your strut and wings. On my Moses Silente, the rear bolt locations are just in front of you back foot. A friend's Sword mounts centered under your back foot. See if you can get a production strut and see how yours compares.

Regarding boards, I would go for the directional and cut off some of the narrow tail. It won't help much in early planing and will make the board more difficult to maneuver in the water. The directional rocker should be better for recovering after splashdowns and the 3 footstrap setup is more comfortable IMO.

[Denisesewa]

The strut attachment location will be based on your strut and wings. On my Moses Silente, the rear bolt locations are just in front of you back foot. A friend's Sword mounts centered under your back foot. See if you can get a production strut and see how yours compares.

Regarding boards, I would go for the directional and cut off some of the narrow tail. It won't help much in early planing and will make the board more difficult to maneuver in the water. The directional rocker should be better for recovering after splashdowns and the 3 footstrap setup is more comfortable IMO.

Well, its going to be tough finding a factory foil in colorado, I am in the proccess of building 3 , one for me, one for my friend who supplied the boards and another one for shallow water ( short strut) and to let others try.
The best thing I can think of is to place the strut so the front wing is basically centered between the original footstrap locations, after riding it strapless we will know where the front straps should go and then know how much can be removed from the tail, I think I'll end up cutting about 4 or 5 inches off the tail. the rocker profile and outline for both boards is virtually identical from the center forward so splashdowns wont be any different, the " directional" is actually a Mutant.
Like I said, these may not be ideal

[Peter_Frank]

"After riding it strapless we will know where...."

So you have experienced hydrofoilers in your area ?
But you dont have any production hydrofoils ?

What are he/she/they riding then ?


Because, I would not count on being able to ride your homefoil yourself strapless

You also write "we", so assume you have someone to ride it for you.

I know it sounds tempting to ride it yourself, and "how hard can it be ?" - but a very bad idea IMO, if you are not experienced, OR have an experienced friend who can do it, no matter what...

It will take forever till you can ride strapless yourself, AND, you dont know if something is totally "wrong" with the trim of your own creation

Of course you might hit it bulls eye in first take, and you will get along fine (only strapped) - but will just warn that you might also end up not getting along

So you should either let an experienced ride it the first time, OR, mount two straps and try yourself, eventhough not the best way IMO.

(and sorry if I am doing you wrong, and you can hydrofoil without problems beforehand, and just need technical inputs for your homebuild)

PF

[Denisesewa]

"After riding it strapless we will know where...."

So you have experienced hydrofoilers in your area ?
But you dont have any production hydrofoils ?

What are he/she/they riding then ?


Because, I would not count on being able to ride your homefoil yourself strapless

You also write "we", so assume you have someone to ride it for you.

I know it sounds tempting to ride it yourself, and "how hard can it be ?" - but a very bad idea IMO, if you are not experienced, OR have an experienced friend who can do it, no matter what...

It will take forever till you can ride strapless yourself, AND, you dont know if something is totally "wrong" with the trim of your own creation

Of course you might hit it bulls eye in first take, and you will get along fine (only strapped) - but will just warn that you might also end up not getting along

So you should either let an experienced ride it the first time, OR, mount two straps and try yourself, eventhough not the best way IMO.

(and sorry if I am doing you wrong, and you can hydrofoil without problems beforehand, and just need technical inputs for your homebuild)

PF

You do me no wrong
I live in Colorado which has no water kiting to speak of, my friend lives in Texas on South padre Island where I go for several months in the springtime, I will finish the first one and send it to him, he may be able to find someone who has experience to ride it first.
My only experience is from 2007 when I built a homemade foil, I was able to ride it after alot of effort ( mostly in a straight line) untill I hit the bottom at speed and broke it losing the front wing, I also fractured my ankle, at that time no one was interested in foils so I just gave up on the idea but now with people riding strappless I am interested again.
this is the foil I built back then.

[revhed]

" I also fractured my ankle,

This is exactly why 1 (one, front only) foot hook is simply the the set up learn with.

@D Do you think you would have still hurt yourself if exactly the same thing happened but only with a front half cut foot hook?
Please everyone listen well.
DO NOT learn with a rear foot strap, PERIOD!
And if you insist on a front strap please make it as loose as you can!!
I also hurt myself badly in 2008 being uninformed and using tight front and rear straps.
As for strut placement on a board.
If you want to adjust it to the front strap (foot hook) consider your stance.
I feel 60cm is about normal.
Eyeball your front wing 1/3 chord from the front and consider this your "lift center"
So if you want a 60 cm stance mount the lift center 30 cm behind your front foot placement.
This is of course a rough starting point.
R H