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Footstrap position and reinforcing tuttle box

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Created by sausage Wednesday, 15 May 2019
sausage
QLD, 4781 posts
Wednesday , 15 May 2019 9:05PM
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I've finally taken the plunge and on some excellent advice from Azymuth, purchased a Slingshot hover glide 76 (it is an intimidating piece of kit to say the least). It arrived the other day (thanks Jesper) and I have decided to repurpose my less than regularly used 2012 iS117wide as my foiling board. I haven't plugged the foil in and ridden it yet as I really want to reinforce the fin box and insert inboard plugs for the footstraps first before stressing the board.........any advice on optimum position would be greatly appreciated i.e. do I keep them in line with existing and just bring in 2-3cm or should I look at bringing front ones back and in???

I have included some photos of the foil (position B) in relation to the existing strap position for reference. As you can see the centre of lift is not centre between straps but I am told that the glide is pretty forgiving in respect to feet position???? I know position C would bring lift closer to centre but I've read it's not ideal to learn to foil in this posi (please correct me if wrong)








In regards to reinforcing the fin box, my idea is to add carbon / fibreglass layers top & bottom & possibly try to key some of the layers into the side of the fin box itself for lateral strength. My theory is that the foil wants to punch up and sideways through the board so layers on bottom more critical but extra around bolts essential also - yet again would appreciate any experience in this method

azymuth
WA, 605 posts
Wednesday , 15 May 2019 9:46PM
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Stoked you've got it - let us know how it goes


I moved the Tuttle box forward 15cm (early days with the Naish WS1 which has less lift) - not sure if it's necessary with the SS wing.
You can always try C position if you need more lift.
I glassed the sides of the Tuttle box to the top and bottom of the board - a glass I Beam.

I would get a few sessions in before you reinforce the box - then you can reinforce and move it forward at the same time if you want your back foot over the mast.

Rear footstraps were maybe a touch too close to the centreline for power upwinding but good for downwind.
Front position's great.
The big spread (44cms) between the footstraps works for me - transfer weight on the back foot to get going in light winds and transfer weight well forward to counteract increased lift when flying down waves and swells

segler
84 posts
Thursday , 15 May 2019 11:46PM
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Rather than estimating or guessing about center of lift position, you can measure it exactly. See this youtube:

sausage
QLD, 4781 posts
Thursday , 16 May 2019 1:12PM
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Cheers JJ...some additional food for thought. I'll probably just go for a test run on the iS137 85cm wide board this weekend to get a feel for it as i've already started to stuff around with reinforcing the iS117w. Also I need to get some longer M10 cap head screws to fit the 117 as the fin box doesn't have chimneys (unlike the iS137). I'm going to leave the fin box where it is as there's always position C as you've mentioned.

Segler,
Thanks - I have watched that vid before and my photo shows the foil (position B) in exact position in relation to footstrap position (it's not a guess). I have attached photo indicating centrelines of footstraps (burgundy lines) and what I assume would be the approx. centre of lift (white line) that said, can anyone actually elaborate where the centre of lift is on the 76 wing?). I'm going to fit 5 hole footstrap plugs inboard to give me a good range of adjustment to find optimum position. I'll take some photos of the process and post progress.




2keen
WA, 37 posts
Thursday , 16 May 2019 2:23PM
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Hi,

Some photos of SS Foils in relation to the Wizard 125.

The infinity 76 has the fuse in the B position, which pushes the lift quite along way forward. I find it comfortable to foil with front foot in the strap and rear foot infront of the rear straps, ie weight evenly balanced. I would guess therefore the centre of lift is probably further forward than your white line.

I find for the Timecode 68 to be balanced similar to the Infinity 76, I need to switch the fuse. The photo shows the Timecode in the C Position.

JJ's suggestion of getting some sessions before serious mods makes perfect sense.

Hope you get as much joy from Foiling as I am!!

Simon.






sausage
QLD, 4781 posts
Friday , 17 May 2019 9:33AM
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2keen said..
Hi,

Some photos of SS Foils in relation to the Wizard 125.

The infinity 76 has the fuse in the B position, which pushes the lift quite along way forward. I find it comfortable to foil with front foot in the strap and rear foot infront of the rear straps, ie weight evenly balanced. I would guess therefore the centre of lift is probably further forward than your white line.

I find for the Timecode 68 to be balanced similar to the Infinity 76, I need to switch the fuse. The photo shows the Timecode in the C Position.

JJ's suggestion of getting some sessions before serious mods makes perfect sense.

Hope you get as much joy from Foiling as I am!!

Simon.







Simon,
Thanks for the valuable advice. That's reassuring to know the centre of lift is further forawrd on the 76 foil. i'll just do a temp reinforcing job on the iS117 and test it before making any mods & inserting footstrap plugs. Now to locate some longer M10 SS 316 bolts!

PS - For the first time ever I'm hoping for the wind to back off here over the weekend

CAN17
213 posts
Saturday , 18 May 2019 6:02AM
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Select to expand quote
sausage said..

2keen said..
Hi,

Some photos of SS Foils in relation to the Wizard 125.

The infinity 76 has the fuse in the B position, which pushes the lift quite along way forward. I find it comfortable to foil with front foot in the strap and rear foot infront of the rear straps, ie weight evenly balanced. I would guess therefore the centre of lift is probably further forward than your white line.

I find for the Timecode 68 to be balanced similar to the Infinity 76, I need to switch the fuse. The photo shows the Timecode in the C Position.

JJ's suggestion of getting some sessions before serious mods makes perfect sense.

Hope you get as much joy from Foiling as I am!!

Simon.







Simon,
Thanks for the valuable advice. That's reassuring to know the centre of lift is further forawrd on the 76 foil. i'll just do a temp reinforcing job on the iS117 and test it before making any mods & inserting footstrap plugs. Now to locate some longer M10 SS 316 bolts!

PS - For the first time ever I'm hoping for the wind to back off here over the weekend


Thanks for the pics guys!

I realize SS bolts are a massive M10 and metric but what does "316" mean? Thread type( pattern)? That sucks that local windsurf shops don't carry these. The bolts that come with the foil are 45mm long right?

Did you have to drill out the bolt holes in your iS117w. If so, was waterproofing necessary. I realize you will do some beefing up anyways but I've heard most people have to drill out the old holes to accommodate M10s. Some say waterproofing is unnecessary but some do it to be safe.

Stretchy
WA, 443 posts
Saturday , 18 May 2019 8:01AM
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I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?

sausage
QLD, 4781 posts
Saturday , 18 May 2019 12:35PM
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Can17, 316 grade stainless steel. And you can just drill bolt holes out without waterproofing .

Stretchy,
Photos below of reinforced bolt area and bottom around the box. not the neatest job but in general I think it'll do the job. Bolt area effectively has 3 layers of carbon / 2 glass (two 50 mm strips either side of centreline and then two 50mm x 100 long carbon strips over holes then a layer of 4oz glass, then carbon then a sacrificial layer of 4 oz glass so I could give it a sand without going into carbon layer). bottom was pretty much the same layering. Have also made a leash for the foil by drilling hole for formuline leash (which will be screwed into a footstrap plug).

i'd push a couple layers of glass or carbon into the chimneys and wrap over deck and then layer up just to tie the box to the deck albeit if the bolts come all the way through to deck then it may not be necessary??









Windbot
73 posts
Saturday , 18 May 2019 10:48AM
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Nice job! I especially like the leash hole idea.

Stretchy
WA, 443 posts
Saturday , 18 May 2019 11:16AM
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+1 nice work, thanks for posting. Leash arrangement looks great.
do you think the bottom layup will compromise slapping much due to negative rocker?

sausage
QLD, 4781 posts
Saturday , 18 May 2019 1:22PM
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Stretchy said..
+1 nice work, thanks for posting. Leash arrangement looks great.
do you think the bottom layup will compromise slapping much due to negative rocker?



No I doubt it ......i just checked and it still has a very small amount of rocker (1mm) at the tail. In fact I think it'll still perform in standard windsurf mode

Paducah
336 posts
Saturday , 18 May 2019 1:06PM
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Windbot said..
Nice job! I especially like the leash hole idea.


Alex Morales in the States has been doing this for a long time on the foils he builds.

See the 4th pic in this insta post: www.instagram.com/p/BtWJC9tHPKG/

jamesf
NSW, 880 posts
Monday , 20 May 2019 12:38PM
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Stretchy said..
I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?



I used the aluminium plate idea to try and distribute the force across evenly across the deck. I put rubber tyre tubes between board and plate to try and spread the load. Unfortunately all that did was cause cracks around the point where the chimneys meet the deck, and finbox eventually failed. on the upside, that meant i had an excuse to buy a proper foil board

One of the local guys here uses a similar is117W with Slingshot foil and loves it, so give it a try before you spend a lot of time on new inserts etc.

sausage
QLD, 4781 posts
Monday , 20 May 2019 1:10PM
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jamesf said..

Stretchy said..
I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?




I used the aluminium plate idea to try and distribute the force across evenly across the deck. I put rubber tyre tubes between board and plate to try and spread the load. Unfortunately all that did was cause cracks around the point where the chimneys meet the deck, and finbox eventually failed. on the upside, that meant i had an excuse to buy a proper foil board

One of the local guys here uses a similar is117W with Slingshot foil and loves it, so give it a try before you spend a lot of time on new inserts etc.


jamesf,
Out of interest are you able to confirm he just uses the current footstrap positions?

Stretchy
WA, 443 posts
Monday , 20 May 2019 12:10PM
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jamesf said..

Stretchy said..
I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?




I used the aluminium plate idea to try and distribute the force across evenly across the deck. I put rubber tyre tubes between board and plate to try and spread the load. Unfortunately all that did was cause cracks around the point where the chimneys meet the deck, and finbox eventually failed. on the upside, that meant i had an excuse to buy a proper foil board

One of the local guys here uses a similar is117W with Slingshot foil and loves it, so give it a try before you spend a lot of time on new inserts etc.


Useful feedback James, looks like Sausage's recommendation of laying glass across the deck and down into the chimneys might be best approach

azymuth
WA, 605 posts
Monday , 20 May 2019 4:04PM
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Stretchy said..
I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?


Stretchy - you've probably already figured it out but I would look at freeride/surf foils rather than high aspect race type foils for the Futura.

Stretchy
WA, 443 posts
Tuesday , 21 May 2019 4:54PM
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azymuth said..

Stretchy said..
I don't have a foil yet, but when I do I'm thinking of nicking my son's Futura 122 and reinforcing it a bit along the lines of Sausage's ideas. My board has Tuttle box "chimneys". I was was thinking of filling them in and either layering some glass over the top or use a wide ally pressure distribution top plate. Good or bad idea?



Stretchy - you've probably already figured it out but I would look at freeride/surf foils rather than high aspect race type foils for the Futura.


Yep, that my understanding, I'm just thinking of light wind freeride for now. Slapping when the wind picks up, I'll never tire of the exhilaration of bouncing over the chop. I prefer driving to flying also. Of course it remains to be seen if I'm still saying the same thing a couple of years from now!



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"Footstrap position and reinforcing tuttle box" started by sausage