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Messages - JohnnyTsunami

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1
The Shape Shack / Re: Rail Structure and Impact Resistance
« on: December 17, 2023, 08:37:29 PM »
A rounded section with 10oz of carbon/glass should be quite strong, although you might be pushing your paddle handle on it when you get up to your feet like I do.

People have been mentioning your construction around and I'm curious. I think you use XPS and gorilla glue? Isn't gorilla glue just foaming PU resin? PU resin that is foamed (or any resin foamed) at all is likely far, far weaker than a composite using neat resin. It might be an order of magnitude weaker, for example. It's really impossible to know anything besides that it is far weaker. Have you done a test of a flat sheet using GG vs epoxy on carbon to test the strength?

2
The Shape Shack / Re: Maximum Displacement Hull Speed
« on: April 04, 2023, 08:01:15 PM »
There http://is a similar chat going on at one of the other forums and there are a few firsthand comparisons between harder chine boards (barracuda) vs softer chine displacement hulls (Appletree, Chapman, Gong) and several people say the speed of the softer chine board makes it easier to takeoff than the hard chine.  Perhaps designs like the barracuda  overstating the impact of “release” and compromising speed too much?  Early days here…

That was my hope! Thanks for the info. The more I thought about it the more like an Olympic sprint single canoe I was thinking of.

https://www.plastexboats.com/pliki/Hydromechanics-of-Sprint-canoes-ver-final+.pdf

3
The Shape Shack / Re: Maximum Displacement Hull Speed
« on: April 03, 2023, 09:04:33 PM »
Just wanted to comment on the "bob" that is done with SUP foils and is likely not factored into anyone's historic equations. The video of the 1st page with the SUP racer you can actually see the tail sucking water up the back just like the scientific a/b test of the canoe and the planing hull. The SUP sucks the water for only a portion of the stroke because the board sort of gets out of the water in conjunction with the riders momentum and seems to almost plane for a moment.

These race SUPS have hard a vertical stern section to allow for this - I believe - as do the barracudas.

I have watched a world class SUP foiler get his sup up in flat water. Bobbing was a major factor. In fact, he mounted the same foil on a friends board +20L with a wider tail. The tail produced so much lift that he couldn't get it to sink for a pump and couldn't "bob" the board and pump the foil. Something to consider.

As with all things foiling I think there is a golden area. Bigger is safer and "easier" to not fall on, but actually harder in every other way.

I have a 4'8" wing board with no bottom contours and a vertical tail rail. The thing indeed won't go above 3mph slogging (I have been passed easily by beginners slogging on their 6' 130L boards!) But, I can pump the s*it out of the thing and unstick it and get it going 8-10mph required to take off on <600cm foils easier than a bigger board with rounded tails.

I'm building a SUP DW board, 7'6" x 19" 100L. I have it shaped with zero hard chines. I'm hoping it will get me up to speeds where I can bob the foil and catch big swell. Inspiration from KT's board for Kane. Maybe something there in ditching the chines. Obviously they would be good for clearing water at planing speeds, but just cause drag below those speeds?

instagram.com/p/Cosy8HiuTaL/

https://www.instagram.com/p/Cosy8HiuTaL/


4
The Shape Shack / Re: Ultralight Board Designs
« on: January 30, 2023, 10:31:40 AM »
Use 2mm Eva foam for the deck pad. 1/2 the weight of any “traction pad” material available anywhere. You will have to scuff the surface or put holes in it somewhere to get 100% traction. I ride mine untouched though because I’m lazy/haven’t figure out a slick way to add texture.

5
You should ride with your weight balanced, especially when switching feet. Start there. Then figure out what your problem is. Sounds like you know the problem, so... what's the problem? Move back.

Typically, your feet don't end up in the right place and you breach because you end up too far back or forward and you're not sure what's going on for a second and you lose your balance on the foil. A front footstrap helps a LOT with this since you will never have any doubt about your front (most important) foot. It will be in the strap, or you will have kicked the strap and know how far off you are.

Absent a footstrap, you should have some sort of marking or indentation on your deckpad where your front foot goes (i.e. "a couple inches from the end," or "right over the last holes" or something like that). Personally I had to actually look down exactly when my new foot was about to land to make sure it was going far enough forward. Like .2s looking down. Once your foot is down and in the right spot, have CONFIDENCE that you are in control of the board. Thinking you aren't in control is the same thing as not being in control in my experience on the foil.

Work on the little pop as well, ride low, pop up, switch and come down all set on the other side. You can work on that without switching your feet.

Land practice is great, just do it in your living room. If you can nail the swap on land there is nothing at all stopping you on the water, just the good ol' brain overthinking.

6
The Shape Shack / Re: Ultralight Board Designs
« on: January 27, 2023, 08:45:24 PM »
Here is my setup. It’s very important to throw away the headset it comes with. You need reliable clear sound. I’m using this cheap $30 Sony headset. It works ten times better than the junk $2 headset it ships with.

I drilled a hole through the goretex plug and fit a plastic tube. It fits tight. No sealant required.

One single invisible leak anywhere on the board will make the detector scream loud and possibly confuse you. When you find the leak, cover with masking tape and continue the search.


Now THIS is the sort of tips I need! Unfortunately these things are expensive :(.

I've resorted to doing the microballoon finish, sanding perfectly smooth with some pinholes no doubt. Seems like mixing microballoons gets air in the mix. Then just do a resin only hotcoat (pigmented like the one below it and sand that flat and polish if you like. Should seal up very well for minimal weight gain. 

The only other thing is that if you have multiple layers of carbon/glass and you did a sealing microballoon coat of your board, you shouldn't have to worry. I'm neurotic now after my first board was laid up too dry and resulted in a major weight gain.

I have seen the aussie windsurf build video say he rubs on "porefill" that fills any pinholes, then it gets absorbed by the epoxy layer later. But I can't find any info on that stuff anywhere.

7
The Shape Shack / Re: Ultralight Board Designs
« on: January 11, 2023, 10:58:37 PM »
A brand name for spread tow carbon. The same weight and strength fabric will be ~20% lighter or so using that instead of other weaves because the epoxy doesn’t have to fill as many kinks in the carbon weave.

8
The Shape Shack / Re: Ultralight Board Designs
« on: January 10, 2023, 10:16:05 PM »
When I made my last board (4’1” prone) I was thinking of ways to do closed cell foam skins. I’ve done Dcell on 1lb eps but the trouble is how much epoxy it needs to stick, even as a thickened mix. I was thinking gorilla glue would be good except that I can’t really spread it thin evenly on the board quickly, it’s pretty viscous especially for 1lb eps. Pour foam or pour epoxy was my answer and I started a thread on it.

Well after talking to a few crissy guys they just go 1lb eps and do 4 layers of carbon on the deck and one on the nose and wrap rails. Seems like it’s less durable but you will have no problems with dings or delams or boxes coming out of you do it well and avoid hard objects. If anyone can show me how to make it lighter I’m all ears but they are putting out sub 8lb 75L boards including the pads. I think even a 100l 7’3” DW sup under 10 lbs. I’ve done deck sandwiches, standing area sandwich and full board sandwich. Next is just carbon on eps and a patchy white finish job using textreme.

9
I cut some .01" polyester shim stock to a shape. I settled on 3 shims for this foil. You can see how the fuse is bent in the rear with the shims installed. I'm sure others just use round shapes/washers. This foil is a funky old proptype so it needs shims to work. I haven't shimmed any new ML stuff made for winging yet. I know some extremely fast wingers who never shim ML stuff, others shim and find less lift at high speeds is better with certain front/rear wing combinations. Anyway it's a whole topic of discussion...

I found for this old B3 fuse that with .03" / 1mm of shims the angle relative to the front wing went from 2.5 to 2.0 degrees. Over shimming is bad for the mast. It looks like the whole thing is tilted but it isn't.  ;)

I measure the angle using the delta method, but this isn't necessary for anyone to do. https://www.youtube.com/watch?v=jTCyag5N_vE

Anyway, sorry to get this thread off track.

10
Guys you are straight up wrong about ML shimming.

You can change the angle of the tail and not change the front angle. I have done so and measured it and tuned it. Like I said this is the design. Racers use this all the time. I even linked to it. I know it’s hard to comprehend, I was shocked too when other people who raced them told me about it.

The fuse has three 1/4”x20 bolts connecting it to the mast. Behind that is a smaller bolt. You shim under that bolt and torque it all up. This FLEXES the fuse between the rearmost large bolt and the small bolt you have placed a shim under. This changes the angle of the tail wing relative to the front wing (front wing and front 4/5ths of the fuse do not move).

I have changed the relative angle of the front wing/ tail wing on one mast from 2.5 degrees to 1.7, for example (which is a ton). This did not change the angle of the front wing.

If you want more info PM me or email mike or stephano.

11
…People doing 40+ knots and (kite)racing for their livelihood. You don’t have to.

12
"His thoughts in fixed stabs. No shimming allowed."

NO!

You can shim mike's lab fuses. In fact, they are designed to be shimmed. I keep running into people who don't know this, some of whom own his gear lamenting how they can't shim it, lol.

http://www.mikeslab.com/instructions/

Look forward to the interview.

13
I’ve heard there is “no wind” for the rest of the winter. Is this true or does it mean 15 knots every day instead of 30? Trying to decide between maui and Baja for a little December trip.

14
What density eps are these boards?

I’m in the middle of a prone board and have carbon on one side and some ripples from my peelply on the rails. I’m wondering how to deal with these (sand away the carbon or fill around with microballoons?) so if he could go over finishing and cleaning up between overlapping sections I’d appreciate it!

15
Wingsurfing, Windfoiling, Wingfoiling, Wing SUP / Re: Plastic Buckles
« on: December 02, 2022, 04:13:45 PM »
It's an "older" one. Things age fast in this sport! It's an actual buckle that clips together, not just the place for the webbing to turn like they have now. One of the two tongs on the clip broke.

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