Safety with eFoils


I am sure some have seen:
No prop guard and shipping with LIPOs.

Here is their explanation why they think it’s safe:

Why don’t you have ducted propeller?
Many projects use some Kort nozzle (non-rotating ring) around the propeller claiming it as a safety and efficiency feature. The true is, when falling from hydrofoil board, you will never fall on its bottom! The same way when falling on bike you will never fall on your wheels .When using hydrofoil with kite, this rarely happens, but it is always kite that is towing you over the foil after you felt.
In accord with manual you are supposed to switch ON the board by remote control not until you get to deep water. Having it ON is well signalized. Disobeying this common sense rule, you may obviously harm yourself or others when manipulating with the board. At this point open propeller is more likely to cause injury, but less serious than most ducted propellers. Getting anything between the duct and propeller is fatal. To be ducted propeller called more safe, needs to be prety long,100% preventing anything to reach the propeller. We have not seen any like that so far.
Efficiency increase works at this propeller size to 4-5 km/h, anything over that just increases drag.

I can tell everyone from my own foiling experience with SUP foils, efoils and kite foils that this is total BS. Yes you can fall on the foil. And you can fall into that open prop.

My concern is that if companies don’t take safety serious we will be shut down quickly.

What is everyone thinking?


I completely agree with you… the sharp edges are a magnest for falling riders…
With a kite, you quickly get used to pull the bar to get away from the foil at the first sign of falling… but you only learn that because the first few falls were very painful …

Mast length play a big role though… for surf foiling, i used a 2ft mast, and even if i often fall on the wings/mast, they hit me in the legs… less painful that being hit in the ribs with the long mast used for kite…

i can’t comment for the efficiency side of things…


I’m just getting ready to cut the openning in the mast for wires and cutting the motor wires to length, would you (and others) recommend going for the short mast or the longer mast (I have both)?


This sounds unprofessional! non ducted prop is really dangerous (lipos as well)!!! With duct you may loose a finger or toe,l, unducted you may slice your face/skull open!! The best would be a proper rider detection and duct combined!

I would say a fall towards the prop is most common place to fall, especially beginners on efoil. Had my friend smash his nose into the mast, could have gone real bad without duct.


With a surf foil, short mast works, because you have the full 2 feet to manage you flight (and it helps so surf in shallower water)

With an E-foil, you loose some height as you want your propeller to stay in the water. ( I can’t comment on their claim that if the propeller breach the surface you’ll only loose power and slightly go down)
If your propeller + fuselage clearance make you loose a foot, that’s not much left for adjustment of your altitude and/or the chop.

Also, i can easily swap mast on my surf foil and put a longer one for use with the kite. When pull by a kite, you angle the board quite a lot on the side to go upwind, so the long mast is kind of mandatory.

But with an E-foil, even if you motor is attached to the fuselage, swapping mast is much harder due to the wires going through.


I estimate mechanical solutions like a duct around the prop is more reliable than a dead man switch. It can provide some protection independent of skills, circumstances, also others could be hit by the prop. Question is if it moves at all, thereby adding some risk. Or if it stands still and will rotate away if hit by something, thereby deminuishing the forces sometimes…
With their design the prop sits between the foils, fuselage, mast and board. At least it is protected while driving. It is almost impossible to hit someone else with the turning prop, he will be hit by the foils anyhow.
If a duct does not protect your thumb but your fist the question is if the fist was ever at risk with an open propeller.
I feel the motors torque and inertia make it risky to even touch the propeller while spinning, at least from the front.
Of course, if you are running the motor backwards also the unprotected back becomes a problem.
Its also the question how sharp your blades are at all, depends how you make it and what you want- safety or efficiency.
I think a long really protective duct is needed and by this the design is forced in a certain direction, smaller props, lower efficiency. If they want to break out of this convention to gain new degrees of freedom in design and efficiency they may try. Maybe they develop other measures for safety. I would not demonize it completely. A turning prop normally also travels through water with certain speed, so the complete apparatus moves and can hit you. The prop cannot hit you with very high RPM underwater. If you go through all cases it may not be so forbidding. They use a large propeller without sharp edges at low RPM, somehow forgiving.


We take safety in CabraTec very serious!

    1. While riding EasyGoat you are also triggering cut-off switch on your remote… by thumb. No matter your natural reaction is release or push. Once you know you are falling, you will RELEASE-that is fine or PUSH-cut off switch-that is also fine.
      This is why our remote is not right/left handed (03/2018) You have to choose.
    1. Pacificmeister I admire a job you did for the E-foil community, but the safety standards you set-up with some others, I personally do not like.
      You encourage people to build and ride E-foils based on kitefoil wings!
      E-foil total weight is about 20 % more while missing kite lift. It is like learning kite-foil on race wing.
      On such boards helmet is “recommended” ? Is a must !
      We have good prototype based on Alpinefoil. More speed, less riding time, more difficult to start, way less safe. I use helmet on that one and I would not give it to try to smb. who is already not foiling.

When considering safety issues, we should stay clear whether comparing kitefoil/surffoil with DIY Efoil or EasyGoat. I feel sorry for the statement “when falling from hydrofoil board, you will never fall on its bottom”
It was based on my and 2 other riders experience with particular product and as general rule is simply wrong.

No matter your kite level is, you can not turn off 100% power by tiny thumb shift. With EasyGoat you can.
Prop-airing you mentioned is no way reason to fall on our board (as well as going trough 5mm ice)

    1. Do not expect any foil to be perfectly safe. You are flying over water on sharp blades reaching speeds you are not capable to run.
    1. Finally …We are developing the duct. Mostly because some other versions (rental, freestyle/race) are expected next year.

Stay safe and have fun

The EasyGoat eFoil from CabraTec thread - Info for the DiYer

Glad to hear that you will be adding a duct Mira. Stay safe and good luck with your product launch.



Safety is all about reducing the probability of injuries, prop guard is an efficient way to do so. Yes it will still be dangerous, but it’s not ok to put the end consumer in a position where the probability for injury is unnecessary high. If consumers slice their face open (open prop) and their board caches fire (lipos), this awesome new activity could be banned or strictly regulated…


Could we run a comparison of a duct vs a cage surrounding the props ? Would we really lose too much efficiency ?


what about making a “weak” part on the system?

first i wanted to build something strong: gearbox shaft and prop , l had to use hard steel shaft in order to get prefect rotation, but if i hit something hard, it will destroy gearbox and prop so i will had a weak part, made to break first before “me” or the mecanism

i was thinking of using a WOOD or PLASTIC pin to hold the propeller, what do you think?


The pin is supposed to be the weak part on outboarders.


Cool! Yeah make somthing that brakes at about 16NM. Like a sheer bolt:) simple to calculate


the pin is supposed to be the weak , yes BUT in really life, only small engine have prop with pin, on my solas prop the weak part in made around the pin, i don’t think shaft or the 4mm stell pin will break at all!
on my boat (glastron v174), not pin, steel prop, every time i hitted a rock with a boat i broke the prop (alloy) or bend it (steel)


hiorth: 16NM looks a good number to me : calculate … or i have this|Google%20Shopping|224332628|17691923948|424973929645&gclid=EAIaIQobChMIkumY2bqE2gIVrr_tCh0hPAhZEAQYAyABEgI5NvD_BwE&pk_kwd=2717|pla#ectrans=1
test next week


Hi jeff
Could you post pictures to your connexions’ with this safety switch
Do you Need relay ?


This is one of the most spectacular efoil crash pics I have seen :open_mouth:. I can’t tell if he fell on the foil side, just a reminder that we can crash in all unthinkable ways. Be safe!

Efoil for rent in Switzerland

someone know this type of switch, I want to use it! but I do not know if it’s good? for battery from 6S to 16S Lipo, 100A / 200A.interrupteur-securite-70v-100200a-emcotec-a72011%20(1)


That happens more often than not for EVERYONE learning… and why open props are STUPID and down right dangerous. So important to just fall with the board and try not to save it or this is what happens (you fall into blades by design). Thanks for sharing Pacificmeister - EPIC Photo!


Yes that switch has been talked about by others and myself here a bit. bottom line, it cannot handle those currents and other users showed pictures of meltdowns within minutes of use. I use the Flier 400A watrproof ESC and had them build int custom on/off switch, works perfect and no extra charge :slight_smile: