Thanks for that answer I looked around for something like this to tell my parents
I don’t want to underestimate the risks involved in this sport but to put things into perspective my crash test dummy and chief R & D guy is my 12 year old son followed closely by my 15 year old daughter. Both are now accomplished efoilers and are the envy of their mates. I come a close third at 47 years old. I insist on helmets and impact jackets, the rest is just up to them.
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So what’s your setup then and you don’t have a duct right.
But what I want to explain is:
Do you want to get hit at 5000rpm from an aluminium prop with a 7ps motor. I think not and I think that the helmet would not sustain this impact
However thanks for your feedback
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i took me a few pinched fingers before i tried something better :
exact order is:
Remove the alu piece where the wires exit,
Remove the 4 radial screws that hold the part where the big bearing fits
Remove the snap-ring on the shaft and the washer below.
That should allow you to extract the stator.
mis-using a clamp like that work smooth,
Before i was using 2 sharpies to push it from the bottom (you can see that in my movie), but that’s not safe at all…
Then i started just threading a thin rope from the open side between the windings, and making it come back kind of on the opposite side. Holding the rotor between my feets and pulling on the rope… not much better.
Finally once the stator is out, you can get the shaft out of the rotor after unscrewing the 2 set screws. My original shaft was stuck, so I had to heat up the rotor around it with a torch to make it expand and get the shaft out.
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Thanks I will do that I hope my fingers don’t get crushed I wearing gloves. I had a different outrunner before (smaller) and I crushed my little finger between it when I closed the motor --> ouch that did hurt
My project is getting forward 
http://premier-marine.com/durajet-jet.php
Felix, Let me first say I am beyond impressed with your thihking.
All it will take is one chewed up beach goer to cause punitive legislation.
the above link avoids the need to reinvent the wheel and it provides VAST increases in efficiency compared to a “jet” drive
I am a former R&D engineer with several patents in my name and prior art is the issue with all this stuff
Lastly, WATER gets into everything, so the ultimate solution is a gear case just like in the 50-70 year proven design of the standard OUTBOARD 
In Canada we dont even have a choice!
the link below is 100% safe and is more efficient:
I heard that you are not allowed to have a free propeller In the water. Last week I read in the news the a 19 years old girl got killed from a normal 50ps boat. (She was free diving).
What I want to say with this story is that it is necessary to have such a guard around the prop.
But I cant really engineer anything because I have some tools and a 3d printer and with that I’m building a e-foil. So I need a way how to build such a prop guard.
Thanks I’m really impressed by the jet outboarders and after my efoil build I want to build a jet sea scooter.
My parents are all about safety and they are my sponsors so I need to do what they say to me.
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What is that more efficient than?
@Mat i did it tried it with a pulley and it worked fine
and my rotor looks damaged I think I got a used one🤨
Ha Ha I am guessing that your parents have hacked your post?
You are correct I don’t have a duct. I’m not adverse to using a duct however running a 80100 setup, as you well know, it is difficult to incorporate.
From experience the prop is not spinning after a bail from the board, instinctively you release the throttle and as such the real threat becomes the mast or wing.
I’m certainly not advocating complacency when it comes to safety but you do have to look at what direction the pioneers of this sport are headed in. As this sport matures folding props will be the norm, not unlike mountain biking the motor will just become a power assist to get you to the good stuff!
All that said your parents ARE your sponsors and they ultimately have the last word on the subject and I encourage you to take their advice. When you’re as old as me you can go in whatever direction you choose.
Good Luck, I’m off out for a foil.
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I just discovered this topic,so I will place it here as I placed it in another topic.
Just a thought, what if we print a prop with a ring attachted around the propblades ? Much safer and less drag through the water because you don’t need a mount anymore. Yes the ring will spin around but that will not cause injury as a boatprop.
i had that thought but the sidethings wich hold onto the duct are a real friction problem
If you don’t try, you won’t know… the other trail is to thicken the blade leading edge that is a thin airfoil section with a prominent round nose…
I don’t think that’s actually damaged, probably just manufacturing defect … The winding is too clean to be a used one.
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a normal propeller… it avoids vortices
the durajet works and just needs to be scaled down to a six HP motor 
I am semi retired so I have to focus my productive time on sure fire money earners but I was an R&D engineer for about 30 years
No jet drive in any way is more efficient than a standard prop drive. A jet loses around 30% efficiency. I can guarantee if you took an outboard and ran tests and then replaced the drive unit with that it would be slower and less fuel efficient!
the graph shows a higher spped for the jet drive. To me its counter intuitive but if the data is accurate we are stuck with it…
I suspect it is mimicking a higher pitch prop and thereofre using more power… anyway unless the graph is fake…
