El Cheapo Foil Drive

[PonoBill]

A little video of my cheapskate foil booster (and a basic ADHD demo). If anyone is interested I'll look up the company I bought the powered fin from, but they are fairly common.

[PonoBill]

The fin drive was about $400, including the battery, controller, etc. the only other cost was twenty bucks for a chinook fin box from fiberglass Hawaii.

Of course shortly after I made a special trip one-hour round trip to Kahalui to buy the box I spent two minutes looking for a good place to store the extra mast box I bought and found my stash of inserts, PVC blocks, mast and fin boxes. I had five chinook fin boxes and five mast boxes. Now I have five fin boxes and six mast boxes.

Moron.

[SUS4Life]

Nice, following this thread for more updates.  I was also looking in to meshtastic communication but haven't found a use for it yet since I mainly surf but I can see it will be a good use for DW without cell reception. 

Do you plan to chop the fin portion off since it just creating unneeded drag once you have a foil on it?

[SUS4Life]

here is another option using underwater scooter, just need make mount or possible bolt it directly on to the foil mast.  Looks like have less range 30-45min and 3mph top speed.  But you don't have to deal with wiring or battery pack and put the weight right under the foil.

[red_tx]

Pono, awesome rig.

My takeaway however is that I am not the only wierdo walking around with socks in flipflops..

Thanks for sharing
-red

[surfcowboy]

This is cool to see. And yeah, a couple of mods and that thing will be perfect.

Seems like this will be ripe for a 3d printed mast mount before long. Can't wait for ride report.

[PonoBill]

My takeaway however is that I am not the only wierdo walking around with socks in flipflops..

I don't usually do that since it's so very haole geezer, but it's been cold as hell lately, all the way down to 65. Little known fact, water freezes at 65F in Maui.

[SUPJorge]

I'm following this closely and have the same question as SUS4Life: "Do you plan to chop the fin portion off since it just creating unneeded drag once you have a foil on it?"

And, yes, please shoot tell us where you got the fin, and a bit more for us slow ones of how you attached it to the board.

[SUS4Life]

Any update on the el cheapo foil drive?  Were you able to get it to foil with just pumping or you need a few hard strokes to get it on foil?

[PonoBill]

I have indeed trimmed off the fin. I was having some problems with the power which turned out to be a bad spotweld in the battery pack. Fortunately, I have the guts of a spot welder I was going to build here in Maui, so I breadboarded it together long enough to zap the strips and get them connected much better.

I was going to try it today at Ka'a but my knee is screwing with me. I was barely able to stand on my big Kalama board, never mind on the little Flying Dutchman I installed this on. I'm going to get a PT to bang on my knee, and probably get someone more agile to give this a go.

[surfcowboy]

I just wanna know if you can install it in the back of one of your existing boxes with the mast all the way forward.

[PonoBill]

Hmm. I didn't think of that. Probably not, If I had one of the long 14" Chinook boxes then maybe, but probably not with a 10". I installed a Chinook fin box between the mast boxes to mount this thing. There isn't room on the Kalama board to do that. It's about 1/2" short on clearance.

[surfcowboy]

Yeah I'd figure. Bummer though.

I'm hoping if this thing works that people might design a 3D printed case for them that uses 2-3 FCS plugs or something less obtrusive.

I love that you are hacking these things. It looks really good.

[juandesooka]

I too will be curious to hear how/if it works.  I am on the waiting list (maybe forever maybe never) for a Boost Fin, same idea.  The knock on these is they are low power small battery, maybe not enough boost.  Our crew is also building DIY FoilDrive (FauxDrive), testing in next couple months hopefully.  These are mini e-foils, quite a bit more juice than Boost or equivalent. 

My board has a tuttle mount (gofoil) with tracks too, I am thinking a fin like this could probably be installed into the mast boxes behind the tuttle.  But for boost, my intention has been to install FCS mounts behind, as it comes with an adapter that fits into FCS.  That is, if not a complete scam / hoax.

Anyways good on ya for tinkering and dreaming.

[PonoBill]

Yeah, I'm on the list for the boost fin as well. If it's a scam it's an elaborate one, but having played with this fin with a substantially larger motor and battery I doubt it does anything useful. Which is probably the real reason why we're not hearing anything new.

the bad news for the fin I'm trying is that it's too weak to really do much. It will push the board along at perhaps 2mph, which at first seems like it might be enough to be a help in waves. But the weight added from the battery pack (probably ten pounds) and the general clumsiness and drag of all that stuff make the little bit of boost probably not worth the effort. I still haven't tried it in real waves or swell, mostly because my knee is giving me fits, making it hard to get to my feet just to do ordinary foil surfing. But I'm not seeing much benefit in little swell, which is bad news since they are traveling so slow. I should have been able to paddle fast enough with the added boost to keep up--at least briefly--but I couldn't.

I'll get someone else to try this thing in the surf, but I think I've established the below lower bound for how much power we need for a practical boost. I can't find any spec from the company that sold me this fin for the wattage of the motor, but my guess given performance is that it's somewhere in the 100 watt range. The issue might be propeller efficiency as well, though the folding prop on the successful Australian booster looks fairly crappy as well. I'm surprised that it works as well as it seems to.