Electric Surf Board

I am dead keen on making a jet drive, it seems so good, light weight if made from plastic, small...


do sealed bearings get used to support the shaft?
I had in mind using one right behind the prop, A second about 50mm back and the last one near where the motor would connect to the shaft?
Or do bushings or something get used ?

If I can make these, I would make two of them for a dual jet drive canoe...

http://www.youtube.com/user/MarshallM5011/videos

[youtube]VfVkjx2qh3s[/youtube]

Finished my project...


[youtube]ilNCC6ttRO8[/youtube]

Really good work!

Can I ask what propeller, rpm, motor and voltage you are running?

Hilfe, bitte! Motor, esc, voltage, and prop? What happened to the jet drive? I just ordered a trolling motor prop to get going on my build. I bagged the jet idea myself because I thought it was too difficult and not efficient enough. I'm behind on this thing, I wanted to have something done by this time of year. Here's the prop I ordered, Machete III:

Had to watch the vid again to find out what you'd done. Took a minute to realize you had someone on the dock with the remote. That would make it fun! Did you try and put the remote in zip loc bags to keep it waterproof?
Seriously awesome job on the build. I can't wait to get mine going. Too many problems for me to solve with waterproofing and such. I will honestly pay you for some help on this. It looks like you got a motor mount that fits the motor size you are using? I was going to leave mine open for now if I can't find a way like you did.
One other question for you would be board size. It looks like you are one a 7'6" RRD sailboard and your weight 170? (just a guess). Do you think the motor will push you on a shorter board?
Stoked! It can be done.

Well, finally got a chance to try out the 3 blade prop on an inflatable SUP. I used a 270kv 6364 motor, believing that the torque would be sufficient and wanting higher RPMS. Since no one has been much help on this, I'm going at this blind as a bat. The prop fit well - had to bore it out a bit to get it to go on the prop adaptor of the motor. I've made some ghetto EV's, but the motor mount I made for this was ghettotastic. An all time low for me. A basic Erector set with two crossbars and a metal strap bent upward to hold the motor. Stepped on the metal bar and pulled on it to get the shape. I folded it over for two layers to give it more rigidity. The best Home Depot had to offer in custom metal work. The whole thing is screwed together with whatever I could find in the extra screw bucket. Copious amounts of duct tape was used to cover screws and metal edges, placed some foam over the edges. I used all the straps I could find in the garage to wrap and secure this hunk to the board. Still my biggest concern is getting near that prop and losing an important body part. Wouldn't be pretty for the mount to come undone.

I wired up the motor with a 120a boat esc. Figure its waterproof. I read somewhere that the average kayaker uses 100w will paddling, don't know if that is true or not. A 6364 motor should get me up and running on 6s, it works for my eboards, right? I used some extensions for the phase wires, about 2 feet or so. A Glad container was going to hold the ESC, battery and receiver. I made a small hole and pushed the phase wires into the container. Siliconed the hole. My remote control was double bagged in Ziploc to keep the water out.

I did some dry runs with the battery installed. Everything seems to be okay. I don't really know about the motor direction, if that is correct or not, but figure I can switch wires after I see which way it is going. The prop spins fast, but how fast do you really know?

Grab the kids and head to the lake. Didn't want to make a fool out of myself without my kids around. My neighbor who knows I'm mentally challenged even offered his kid up. I now think he's more mentally challenged. A couple of kids and a deranged man that want to ride a jerry rigged electric paddle board. Who in their right mind let's their kid come along? I told him I'd be lucky if I made it home without an ambulance.

Luckily, the board goes in the right direction. It powers up well. I do a few checks to see if everything is going okay under the deck. Get up the guts to finally sit on this thing. It pulls ahead at a good pace maybe 10 mph or so. This isn't full throttle though. I can't steer sitting down though. So I stand up and cruise for a minute or so at about 3/4 throttle. Its alive! I stop to turn it around and restart. Now the motor is cogging. What the? I check under the board and see a screw that must have gotten sucked in by the magnets. Piss. I go to shore and unplug the battery. The esc is oozing adhesive, feels like its fresh from the oven. One phase wire is loose and I've got some melted wire. I thought I'd toasted the ESC. After waiting to get the ESC cooled down and attaching the phase wires again. I do a check. Still getting the cogging. I then took the extensions out of the picture and hook the ESC direct to the motor. The motor beeps and spins on command. Thank goodness. Problem is without a garage nearby the fun is over for the day.

The question now is whether or not this is really going to work with the current setup. I was going ghetto to see first if it would work with the smaller motor, prop and at this RPM. I didn't know if this would be able to push me at any decent speed. Also didn't want to invest more time into a motor mount for the paddle board if I could get up on a 7' 6" shortboard. I think if it works, I would do a direct drive like RC boats have. Still hate the idea of an open prop. Definitely need a prop protector. I know Lampuga doesn't use one or Matthias. Problem is I didn't get enough time up on the board to really figure out how fast it would go. A bit sketched out to fall and hit a spinning prop at full speed. I'm not real excited to go 5mph or so. 20 is my hope. Looking back on the minute I was standing, I think you would need a higher RPM or bigger prop. I'm thinking of using my HV ESC that I've used on my MX 500 motorcycle build for the next attempt.

In regards to the phase wire extensions - Is there a certain length which doesn't work and is causing the motor to cog? I think the connectors are fine and it still cogged. Should I use thicker wires on it? I have some room to shorten the wires, but not by much more than six inches or so. I could also leave the esc in the water and have the power wires exiting the container instead of the phase wires. I don't know if the ESC is waterproof anymore after the beating it took. Also don't know how the motor will hold up submerged like that without waterproofing. I'm using an extra motor that I've no use for, so if it burns I won't care too much. I thought I'd use the 80/100, but don't really think that is a better option, due to the RPM factor. Might be totally wrong on that though.

I'm open to any suggestions. I'll try and grab some pics when I get a minute. Probably only good to mock me. Kids had fun fishing.

Second go around went about as well. Got it re-wired. The top speed is maybe 6-7 mph. 24 volts isn't getting the job done. I will try once more with a HV controller and see what happens. Positive thing is I still have my fingers. If 48v doesn't work the prop will have to be bigger. I don't expect it to go too much faster though. I don't know where to buy a plastic prop in any bigger size than the Machete.

Hey Dirk, my first ES post. I'm researching a similar project. The main problem is the prop. Trolling motor props only have a 4 inch pitch, good for low speed thrust (pushing heavy boats around slowly) therefore bad for "high speed" low weight craft. Even if you spin it really really fast, it can't be efficient. There is a particular Torqeedo prop that is ideal - designed for about 20kph I think. It's what Matteus above has used, it's also used by the water wolf electric board. Not cheap though. A prop for a motor called a Protruar seems to be a copy of it and cheaper. The other interesting one is the Propel prop for the Native Watercraft pedal powered kayaks. Just bought one, seems to be a 10inch pitch. The design is like the Rick Willoughby homemade props - efficient. No idea if it will work in practice though.

Kas.

Thanks for the reply and advice. It's much appreciated. Also I've been discouraged enough to think of bagging this project and your post helped me have some desire to keep trying.

I also noticed the prop Matthias (You Punk, show my how you did this!) was the same as Waterwolf's. The Torqeedo props are listed for around $100. Seems they have two versions, don't know which is better. A 1915 and a 1901 model. Both have the same writeups, so have no idea the differences. I looked into the Protruar props and can't seem to find just a prop for sale. Although I'm tempted to just buy their whole setup. They have a 24v brushless motor with 110 lbs of thrust. On Ebay it's $550 and would have all the housing. The price is steep, but if it save me $100 for the prop, so really only an extra $450. I would like to find out the motor and controller that they are using. The waterproof housing would also be great to have. A few reviews mentioned they got a 14" inflatable dinghy and 400 lbs of passengers going 8 mph. If you cut that down to 190lbs of me and 25lbs board/batteries/motor, we should be able to at least double that speed. If you can overvolt the motor, I could get to my desired speed. Matthias looks to have a professional looking covering for the motor and prop. He must be using something like this, as the brushed trolling motors have magnets built into the housing. I guess you could remove them, but likely not worth the hassle. What an extra couple hundred when I'm comparing this to all the $10,000 working surfboards that are available. What is the price of my frustrations and time? I'd pay a few thousand for a working version, but not 10. Sometimes building stuff is fun Anyone have any experience with the Protruar?

I read through some of Rick's things on here, I believe he was active on ES, correct? I might have to just try the airplane props that he suggested. I have a few at home and they are pretty cheap comparatively. How far along are you for testing the prop you bought?

Looking into them, the 1915 and 1901 Torq props are the same, but made for different motors - the shear pins are different. So you can choose the one that suits your motor best. The second product image on this page compares the two. http://www.murrays.com/71-1901.html A very handy photo. The 1901 on the right seems to be the "standard" connection used by other (by "other" I mean cheaper :wink: ) trolling motor brands.

It also says they have a 10in pitch, good to know for calculations e.g. for you to go 20mph (that's fast!) and assuming a slippage around 8%, your motor would need to turn it at 2300rpm approx. This is the prop Mattheus is using. There's another one (1916) that has a 12in pitch and can handle more power. This would have the same connection type as the 1915 mentioned above.

I have a 56lb trolling motor (1370 max rpm) that I'll be testing with, and the 1901 just might attach without modification. Fingers crossed it will be powerful enough to get on the plane. I've been researching the jet route and the RC brushless motor route and it's all bit too advanced for my metal fabrication abilities.

I think Rick has mostly been on boatdesign.net.
Re the prop testing, I won't be on the water in the near future, I'm building the craft from scratch at the moment.
Let us know how you go.

Cool, I wonder how long it will be before we need a sticky thread that says "I am a noob and want to build a 50MPH electric surfboard".

Love the concept, but those blades are intimidating. Hoping to see someone out work out the jetski design.

Got some info back about Protraur props. $60. Now what... Buy something tried and true for $100 or go cheap at $60? thanks for the links again. Murray's didn't pull up on any of my searches. The 12" pitch or the 10"? My 6364 motor is 270 kv, so at 24v I can get over 6000 rpm. That's if the motor is up to it. Probably should get the 10" torqeedo. The machete prop has a 8mm 5/16" ID IIRC (could have been 10mm) which I bored out to 12mm to fit the spinner on my motor. Hopefully these are the same. The spinner setup works well so far.

Cool, I wonder how long it will be before we need a sticky thread that says "I am a noob and want to build a 50MPH electric surfboard".

Click to expand...

I wish that was already here, it would make my job so much easier.

The jetski design is what I had originally planned. I have the drive still. It's heavy and will be more difficult to implement, a bunch of extra fab work. I'm going for testing at this point. Proof of concept. The open prop scares me too, but if you get it positioned under the board, shouldn't be an issue. Mikebikerad has it on his paddle board and Waterwolf does too. Jets are supposedly only half as efficient. I think with a decent cage around the prop it'll be just as safe.

Here's the small scale mock-up:
[youtube]7joSzkMzVGA[/youtube]

The jet being more work and heavier and not as efficient to rip your body to shreds?
I want to see you juggle a chainsaw while riding the board, cmon tough guy.

Hi All,
Im also in process of building an electric powered jet propulsion surfboard. Im building the jet drive in cad(inventor) first. Id love to hear some feedback on what size impeller is needed. Also does anyone know of any reference regarding stator design, i cant find anything. I started with a 3 inch diameter impeller. But Im wondering if I need 4 or more inches?? Any thoughts?


Has anyone checked out the TP100 motor from TP Power? its 720kv but it looks like it could generate some serious power. Im also looking at the turnigy rotomax 150cc.

Ideally id like to be able to go 30 mph on the surfboard.

A fast electric surfboard is cool, I want to build one too.

High speed impeller is probably very efficient etc, but a high pitching noise is something I would like to skip.

Building a waterproof case around a brushless motor would run hot, but can be liquid cooled maybe.

Maybe a brushless motor inside the board itself and seal it from water is an idea, but would need a gearing, with extra shaft and bearings and will make noise too I think.

Using a big 110 lbs trolling motor at 24v and mount a high pitch prop like torqeedo, that won't run hot but can probably not run 5 kw.

Maybe this is a stock motor with other prop ?? It is from Matthias his video.

I have build a c80100 Turnigy inside a 110 lbs motor but got into new projects since so never tested it. Also I have made many other electric outboard motors and it is not easy to get several KW completely silent on the water.


But what if we just get prop straight to the motor like a big RC motor from alien power systems and run it all IN the water ?
Like this.

[youtube]dL_5UewOYIA[/youtube]

I think this can run very silent, very efficient, direct water cooling, no extra sprocket, gearing, bearings. after each day just spray some oil at the motor bearings and it will probably run for a long time.
Maybe we can coat the windings with something, but probably it doesn't need extra coating.

But than the RPM.

I believe most props are most efficient at about 2800rpm I believe.
A lot of big brushless motors like Hobbyking Rotomax etc run about 150 rpm/v so at 2800 rpm = 18V. But for a desired 5KW that will take 277 A so that is not going to work.

There is an option to rewind the motor or buy somethink like this: http://alienpowersystem.com/shop/120mm/120100-outrunner-brushless-motor-50kv-25000w-2/

I believe they sell other custom windings too.

So let's take a 50kv motor and let it run 2800 rpm, we want 5kw that is 56v and 89A that is getting closer.


Maybe someone can answer my questions about this:

A 50 kv motor has a very low resistance winding, can we run it with 24 fet ebike controllers ? Maybe sensorless ?

Can't we run a low pitch prop at 5000 rpm ? Cavitation ? If that will work, we can use normal motors and controllers.

Another option would be to get inline 5:1 planetary gearbox (like in Torqeedo outboards) for the 80100 motor. And then run at 18s and with the gearbox, the output rpm should be around 1731.6 RPM (18s x 3.7v x 130kv /5 = 1731.6 RPM). BTW Torqeedo has max RPM of 1300.

I think with the gearbox the 80100 should have more than enough amount of torque to drive the torqeedos high speed prop ( 1923-00 v30/p4000): http://www.torqeedo.com/uk/electric...-sailboats-up-to-4-tons/product-a-accessories
Then you should be able to go over 30km/h

I'm trying to build outboard with that same setup, but I still have to find the gearbox for it. If anybody would give me a link were I could get a 5:1 planetary gearbox that can handle 6-7kw and doesn't cost very much would be epic .

Planetary gearbox would be nice. But will make a lot of noise I think and it needs a waterproof housing and liquid cooling. In real life those torqeedo's make noise too. I have seen this

Electric outboard motor: http://youtu.be/kjdPS-0ZY0Q

If you make waterproof housing for the motor and gearbox under the surfboard then it will silence it. And if you are going 30km/h on water then you wont hear it much anyway . You will hear torqueedo because the noise can travel through the leg and transom mount... but if the whole system would be submerged then it would be so much quieter.

True ! What about that video? Pretty cool how he made that. Unfortunately I can't find videos of the motor running in water

Yeah that was very awesome. The gears looked very small... and what about eddy currents inside that aluminum casing? I'm thinking of something like that in the video, but with clear acrylic cover over the motor and other parts would be form aluminium for better cooling.

I am still waiting on the torqeedo prop. Ended up ordering the 1901 version. The 12x12 seemed a bit aggressive, but we'll see.

I am not sure if Matthias was using a a 63 size motor or the 80-100. The casing seems too small to house the larger motor. Would be nice to hear from him about what he actually used. Hint, hint. I'll be trying mine with a 6364 size motor and the torqeedo prop on 6s first. If that isn't happening I'll jump to 12s. Depends on what blows first.

The video was interesting, but we never got to see what the final result was. I wish I had the machine skills and equipment to make custom parts like that. The prop was the Machete that I used on my first attempts. Not very efficient for speed as was discussed earlier. I like the idea of using a trolling motor casing, but don't know if I'll be able to remove the magnets. A plastic bottle should work well as a temp solution. I am interested in the eddy effects also, and that is why I've opted to try an open motor live in the ROV. I watched a bunch of that guys videos, and he never mentioned any issues. I think if you want to use this in salt water, you'd get some real corrosion issues. I spoke with someone in the Bermudas about RC stuff and he said nothing electronic like that lasts in the humidity and sea air. Good thing I live in a dry state. If things work like hoped, I imagine going to a system like that of an RC boat. Electrics inside, with the motor connected to a shaft that exits the board on the bottom of the hull. Still have the open prop issue though.

Here's something new though:
[youtube]hTdAqrXm9ck[/youtube]

Board is a little more my style, but looks like it could be improved. At those speeds you don't need such a floaty board. I've emailed them, but I'd be very surprised if they aren't selling for less than 10k.
'

Here's another one from Waterwolf (Wasserwolf) fuer die Deutschen:
[youtube]TEd5ud42YaI[/youtube]
Ohne wind, ohne Wellen, Surf trotzdem los!

If I understand correctly the speed is controlled on the board, not by a remote. What he seems to be holding is only the safety leash. When pulled, the board stops. I still don't see how the prop being beneath the board can be optimal. Seems like a waste of power. Curious as to what prop that is as the torqeedos are all orange.

Wow ! Both last videos are nice.
http://www.emarineinc.com/products/Torqeedo-1901%252d00-Spare-Propeller-v8%7B47%7Dp350.html

Can we see somewhere about what pitch each prop is ?