No-wind days: dock launch foiling.

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No-wind days: dock launch foiling.

Postby jv. » Thu Jul 02, 2020 12:34 pm

To enhance my all to weak foiling skills, I have begun to work on dock-launch foiling. YouTube it. Have equipment and raft in my back yard on Little M, anyone that wants to participate let me know. ;). Beats whining when there is no wind, and practice will pay off when we get wind...
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Re: No-wind days: dock launch foiling.

Postby Steve271 » Thu Jul 02, 2020 9:55 pm

Sounds like some great You Tube moments in the making. :D
I think each attempt should begin with “Hold my beer and watch this....”
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Re: No-wind days: dock launch foiling.

Postby jv. » Fri Jul 03, 2020 7:10 pm

Kai Lenny could probably knock it off enjoying a beer, and though when done I surely need my beer, it is tough enough with out a beer that I always wait. Though Stafford and Powerman foil skills may be at a level that they could accomplish it with a beer. I am still shut-out after hours of entertaining Bonnie so far.
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Re: No-wind days: dock launch foiling.

Postby PowerManJ316 » Fri Jul 03, 2020 10:26 pm

All I know is everything in Kiteboarding looks easy when a pro is doing it. :D Then I try it and learn just how good the pros are (and that I am not a pro) :lol:

That being said I am going to be over in the next two weeks to try that JV.

Also keeping fingers crossed for a light Sheboygan thermal on Sunday.
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Re: No-wind days: dock launch foiling.

Postby jv. » Mon Jul 06, 2020 10:21 pm

Well, progress for this old man with dock launching the foil has been slow enough to convince me to use more brain and less brawn. The engineer inside me has constructed a ramp and I am now toying with bungee solutions to augment the ramp. When in Maui last year at Kite Beach I saw some activities that bordered on child abuse as adults were launching kids on foils with bungees (no wonder the kids there that survive become such great watermen!). I borrowed the raw notion but am tweaking the implementation and In the process am providing Bonnie some entertainment. If this works, she is next!
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Re: No-wind days: dock launch foiling.

Postby jv. » Fri Jul 10, 2020 6:38 pm

Ok, in case anyone was watching this for any learnings, my findings so far...

A) Shorter ramp better than longer ramp. Since bungee is the energy source, the farther down ramp you travel the less energy you still have. So, shortest possible ramp (with least friction) is important.

B) Do not underestimate bungee energy needed. I can barely hold the tension needed to get me launched. Still really need more energy, still considering options...

C) Lower ramp better than higher ramp. Started where foil just on the water, but the drop at the end if ramp is almost impossible to avoid as end of board finishes ramp. Tried to compensate by hopping, but when managing an overloaded bungee this becomes unweilding. If ya got enough energy, ya gonna get up on foil anyway so start lower...

D) Clearly, big front foil wing important. I am using Naish Jet 2000cm, which should be enough, flys at 7mph. Considering the 2400, it would be handy for downwinders anyway. Maybe I can convince Bonnie she needs that...

E) Maybe continuing to work on old-school dock-starts is worth the effort - no shortage of youtube video help!! This remains my backup plan and every day I try a new angle.

F) Being retired gives me time to work through this stuff in the lake that is my back yard, but maybe retiring 20 years ago would have made my physical capabilities more up to the challenge. But I keep working on this...
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Re: No-wind days: dock launch foiling.

Postby jv. » Fri Aug 07, 2020 7:00 pm

Ok, probably nobody cares, but in case someone would benefit from my efforts.

A) Have not given up on ramp, now know it can work (elaborate another time) but focusing on bungee launching foil from water. Some good youtube video out there.

B) Bungee learnings interesting. Using a hand winch to load up the bungee. Standard disclaimer - understand risks of winches, measure your load so you know pounds of tension experienced, match each component (bungee, other lines, connections) safely within limits. Experimenting much with bungee (shock line) on 1 inch, 1/2 inch, 3/8 inch and 1/4 inch. There are charts online indicating pounds of force at 100% and more stretch for each, nice place to start. What is hard to find is anything indicating result when you double, triple, quadruple (etc) each size of bungee. I can say with high confidence that the result is not linear, but you certainly increase stored energy. Several online bungee foil examples use 3 strands of 3/8 in bungee (a little over an inch of total bungee capacity). I am presently using a combination of 30ft of 3 strands of 1/2 inch bungee + 15 ft of 4 strands of 3/8 inch bungee plus 6 ft of 1 inch bungee. Why this combination? See next point... I stopped using 1/4 inch bungee regardless of # of strands, too messy and inefficient.

C) The interesting constraint for me turns out to be the winch. Realize the limitation there is having strong enough rope to account for max load, yet enough capacity to hold enough rope to load bungee. I can fit a little over 65 feet of 1/4 inch nylon rope (well over 200 lbs max load I would experience.). The 51 feet of bungee I use (see above) can be loaded over 100% and I have room to maneuver and set line to be ready to use.

D) So, what have I found Regarding inertia that I needed to launch me? Well initially I was trying to achieve my total weight - or 180 lbs including me, board and foil. Problem is, though I can load the line to that capacity, it is impossible for me to hold without an aid, at least not in a position where I can launch under control. I set up various trigger devices to remedy this, but decided to dial back my launch power to see what happens and was pleasantly surprised that I can launch at a more manageable 100lbs. What is actually more important is how LONG I have enough power. That is a place where more lines help. I find having at least 50lbs for at least 20 feet can do the trick (probably overkill for a more efficient foiler). Also, launching with my 95 L board helps, vs a less buoyant board (except in next version with a ramp....). Also, instead of launching directly toward anchor point, angling slightly across (like aiming outside instead of following boat) helps.

E). A unique challenge for me is the fact that I launch from a 8x16 foot raft I have fitted for the exercise. Getting enough anchor to both hold and keep stable when under high load was a challenge, as is doing this in a way that I can avoid and understand any drift. And, as I am in a shallow (3 ft deep water) channel In front of my boathouse, must use my shortest mast and walk the area to clean up any weeds. The good news is boathouse has radio so I have tunes while playing, and Bonnie enjoys making herself useful and entertained. She is good enough to watch the scale as I measure load under various configurations, and record my disasters. However, this is a wonderful and productive way to get through a no-wind day... ;)
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Re: No-wind days: dock launch foiling.

Postby dmonn » Sun Aug 09, 2020 6:17 am

Sounds like fun. I don't know if you've considered amsteel instead of nylon for your winch. It's super strong stuff with minimal stretch. It probably comes thinner than 1/4 inch.

Another thing you might want to consider is a rope puller. It uses 1/2 inch 3-strand rope, but will pull as long of a rope as you have. It doesn't wind the rope on a spool. It's like a come along, but with rope. It has a WLL of 1500 pounds, so you could rig it 1:2 or maybe 1:3 to speed up the process. A rope puller with a come along mechanism would be way slower than a hand winch so you would probably want to speed it up with a mechanical disadvantage setup. Maasdam Rope Puller is what I use in my tree work, and they're $50 at Fleet Farm.
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Re: No-wind days: dock launch foiling.

Postby dmonn » Tue Aug 18, 2020 6:40 am

just for fun, 1/8 inch Amsteel has a minimum breaking strength of 2300 pounds. Pretty cool stuff.
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Re: No-wind days: dock launch foiling.

Postby jv. » Wed Sep 09, 2020 11:11 am

Great feedback Don, and with regard to the rope puller idea that is one I am considering. In fact, on Youtube Kai Leny can be found doing something similar in a setup in his friend's pool, though it is actually a power winch. I have had to set this aside for a while, injured my back running and had an MRI today. Though I have been kiting, windsurfing and wing foiling a lot lately, it has been a bit painful. When using bungie to foil, I find I need about 110 lbs pull to get up, and this bothers my back at the release enough to keep me from doing it until my back is closer to 100%. Although I am not sure winging in waves like I did for 3 hours yesterday is much better, especially when going from knees to standing or when pumping foil in the surf...

That said, I have begun to design a more portable and friendly alternative - a foil launch slide. No need for outside energy, use gravity. Thinking just 4 ft high or so, a flat stand on top, then a relatively steep slide, followed by an angle into water that is favorable for foil. Would use 1" PVC for slide, thinking 3 on each side of foil. Need separate infrastructure on each side to keep foil and mast open top-to-bottom. This would be more portable on my raft, could put it in deeper water. Think I would have to construct in a way that would allow me to vary steepness of drop as well as entry into water so some experimentation would be necessary, but if done right should allow me to practice dock foil launches, or just get me foiling on flat water days. If some ambitious genius reads this and cares to construct before me and sell me a working prototype, feel free to patent it. Otherwise, when I get this right I will report back, but that probably will not happen until my back gets a little better - but we go to Hatteras last week in October, hope to have something by then.
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