Added Carbon fiber Fluke/tail for pumping

Hello all,

I’ve created a prototype of a rear fluke tail attachment which is intended to create thrust when pumping. I’ve only ever kite hydrofoiled, so trying to pump with it will be new to me. I’ve used a LF foil fish with a Glider 125 front wing. I added a 6mmx30mmx500mm pultruded carbon strip to act as the “body”, and a 1.5mmx250mmx500mm panel to act as the fluke. Lots of factors to consider, but I feel like it’s a good starting point after messing around with it in the water. Will be attempting a test session today hopefully.

Check out the video of the water flex test and let me know your thoughts and ideas.https://youtube.com/shorts/gwegGwD8Ovk?si=IbHQDqsoOvotdbSr

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That’s interesting but looks like it’ll take some force to move.

I’m sure there’s a way to use a carbon “spring” somehow. Nike Vaporfly did it for shoes and got them banned from marathons.

On to something. Wakethief tried something similar with limited success. I suspect you will need shorter/stiffer strip and MUCH smaller paddle/stab

Lift fish tail from 5 yrs ago. Pumping was still so nascent that I don’t even know whether it worked or not.

Bigger isn’t always better for pumping though. At some point (a point I think you may have reached) you are just adding drag. A more efficient tail and a front wing with more lift might make things easier.

your drag on that flat stab will be thru the roof , and you have no profile to counter forward pitching

been there :wink:

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Here’s another similar concept, in a different orientation: https://www.fishboat.net

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Caspan - It’s really cool you are trying new things. I wasted over a year trying to dockstart a setup that I couldn’t even dockstart now I don’t think as it was a small front wing and very draggy setup. It will be very hard to learn to dockstart with that setup, maybe you are prone foiling I am not sure. Either way prone foil or dockstart for sure learn to do it on a “good” setup and then add in your new tail and see if its better or worse. There are lots of wakethief setup Axis 1150’s for sale used and cheaper as folks are going to the new Axis foils and the 1150 for sure is one of the easiest foils to learn dockstarting and pumping on. My advice would be to get a used 1150 dockstart setup if you are dockstarting and learn on that and then add your tail.

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Would love to hear an update on it. I’m skeptical that chasing more thrust is going to pay off for pumping, as that thrust is still ultimately coming from the work the pumper puts into it.

Fair point. I don’t have any recent updates on the tail. I’ve been out for a while with a knee injury (getting surgery today) and gave up on dockstarts and haven’t made any testing progress. It’s still an unconfirmed experiment at this point. As an outsider with no experience at pumping a foil, I see the whole pumping motion as means to gain thrust which leads to lift. If that can be improved upon by a carbon spring fuselage and carbon tail which when at an angle it pushes water in the opposite direction then it could be possible that it could be helpful. Whether or not it improves anything remains to be seen.

I’ve made myself two items to aid with the testing for when I’m healed up:
An 1100mm front wing to aid in the pumping efficiency. Similar in shape to an HPS 1050 and a DW board 7’10 x 22”.

Will give another update as soon as I can. Cheers!

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