Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

RC Jet Boat

by bash_tech_ Jan 3, 2019
Download All Files

Thing Apps Enabled

Please Login to Comment

hey mate just wandering if you had any luck with the impeller redesign?

For anyone who's new to RC stuff like me

You need a motor that has the cables coming out of the top of the motor, and not the bottom of the motor
As the motor mounts on the front side of the boat and not the rear

You can either buy the correct one with the cables coming out of the front

Or you can follow this (Could use a hammer if you don't have a press) and push the shaft into the motor, pushing it out of the back and thus reversing it

If I understood what you are meaning, it doesn't depends of cable connection but it's question of inrunner vs outrunner.
See www.radiocontrolinfo.com/brushless-inrunner-vs-outrunner-motor/
Is this right?

Comments deleted.

If anyone is unsure on what I mean (Neither do I really as I don't know the names for the types of motors!)

You require one of these where the cables connect to the top: https://www.hobbywarehouse.com.au/articles/wp-content/uploads/2013/05/brushless-rc-motor.jpg

And NOT one of these where the cables connect to the bottom: https://s7d5.scene7.com/is/image/horizonhobby/EFLM1305_a0?wid=1400&hei=778

Any chance you could upload the step file of the propeller?

Thank you for providing the stp file; made it a lot easier to modify.

so I've been experimenting with different bearings because the chlorine in the pool i tested in ate mine.
the ceramic stainless bearings are really expensive and seem to be hard to get.i don't really trust the rubber seals on them as they are no contact seals since the bearings are suppose to be used in very low friction environments.
the boat bushing i ordered turned out to be a total waste of time.
so i went back to normal bushings. i ordered some 4x8mmx6mm bronze bushings.
to try and reduce the water intrusion from the shaft with bushings. i will shrink the clearance for the 4mm shaft as much as possible and possibly pack the area with grease as a sealant. however this will require a new fill nozzle on the shaft so you can inject silicone grease inside between the inner and outer bushings. this is called a stuffing tube in the r/c boat world.

hopefully i can make some progress on my modifications soon

more feedback from tear down.

In the process of tearing down my boat for redesign:

the 4x10x3 rubber sealed bearings i used were eaten by the chlorine in the pool. looking at 2 options:

stainless steel ceramic sealed bearing 4x10x4 (expensive) and some rc boat Teflon bushings 4x6x5(cheap).
either will require reworking the rear of the boat haul to make them fit.

found out what the fake Chinese stainless parts were as well LOL!

added step files so you can adapt more standard bearings :)

very nice of you. i'm waiting on some samples to arrive before i decide which way to go with the bearings.

version 1 has been an interesting learning experience in what works but doesn't last.

i have modified stl files setup for the redesigned lid and tweaks to the haul. i added ribbing on the rudder seal to have more water protection.
i ran a few test samples for diameters for the insert nuts.

more feedback from tear down.

In the process of tearing down my boat for redesign:

the 4x10x3 rubber sealed bearings i used were eaten by the chlorine in the pool. looking at 2 options:

stainless steel ceramic sealed bearing 4x10x4 (expensive) and some rc boat Teflon bushings 4x6x5(cheap).
either will require reworking the rear of the boat haul to make them fit.

found out what the fake Chinese stainless parts were as well LOL!

Comments deleted.

Добрый день! Подскажите если я уменьшу эту модель на 50%, что может пойти не так?

We did a 50% Modell as well and it worked very nice. you will need a 2mm shaft and m2 screws then.

При уменьшении модели до 50% винт стал очень хлипкий! как думаете не страшно или может развалится? Печатаю пластиком PET-G

Буду запускать в печать ))) Мой сын ждет уже с огромным не терпением.

some observations on my boat and test runs i did today.

1) the top hatch does not seal well. the wall thickness is also to thin around the screw holes. there was some missing perimeters during the print. some water was making its way into the boat.

I'm outputting a new top lid for testing. the entire seal face is now as thick as the haul and completely flat so a gasket seal will hold better.

For the future plans include blind nuts for the top of the haul so the top lid does not have to be screwed into the plastic only there will be a threaded mechanical hold for repeatedly opening and closing the lid

2) my water cooling system saved the day things got hot enough inside the boat haul to melt/soften the top hatch the 70 Amp ESC therm-shutdowned 2 times then restarted a few seconds later. the boat stayed running though 2 4200milliamp packs however on the last run the ESC let off some smoke and the battery puffed up ready to blow. i was using 65c and 130C burst LIPOS.
plan is change from 70A to 120A ESC (different brand) and up the LIPO to 5000Milliamp 100C 200C burst LIPOS.

i used the newer low restriction Jet. still very high amperage use and heat.

3) the boat in general worked amazingly well there was no real mechanical failures. it was extremely maneuverable and easy to control. i must of run it for about 40 minutes between 2 battery packs in the large pool i was testing in.

4) the boat disturbed the water so much i was basically jumping off my own wakes which meant the jet sucked air and stalled out propulsion
maybe add more front ballast i put about 10 grams in the front and 2.5 grams for the battery weight off set. trim was good otherwise.

5) i had redesigned the prop slightly to add more clearance in the tunnel and it worked very well. Prop was printed with Taulman 910.
you will need to use 100% supports when printing in nylon so you get a nice clean output otherwise the nylon will shrink, warp and ruin the prop.

on to the next test run and see how the additional changes pan out.

i will post the changes i made.

yes we are working on the prop as well. it draws to much power. we experimented wit a 2 blade design which helped a bit.
And we want to put the whole yet further to the back that it hopefully does not suck that much air in.
Ah and if you have a driving video i would love to see it.

recorded a video but the resolution is very low. it ran really well. very maneuverable


discovered that the motor heat that blew out the back of the armature, even with the water cooling actually melted the PLA top deck and the top section of the haul nose. Next test i will be installing a heat shield to try and reduce the pla absorbing so much heat. i'm also upping the amp capacity of the running gear.

i will be testing some additional changes to the haul for the deck lid mounts. i may reprint the entire haul from ASA or PETG or maybe ABS because of the extra heat and also better UV and water proofing of the material.

i plan to do some more bath tub testing as well. :D


I'm printing the boat with an Alfawise U20.
No problem for print all parts except the deckel1 and deckel2 (cf. picture, the right have been print in the other side).

I have test to print other pieces and no problem...
Do you have any ideas ?

Thx for your help

Actually, my Cura profile was buggy.
I re-slice it with the default profile with my main tunes.
It print prefectly.

Print the bottom in 0.4 and treated with XTC3D to fill the hole (bad configuration)
Print the top in 0.15 without treatment

Little comment, I had to print the propeller in 95% to fit the hole of the bottom parts.


looks like you have layer shifting there. so you printhead hits the part and the printer loses steps. maybe try with besster cooling. or try printing slower. and check if it is really lost steps. keep me updated

Great work, thanks. I'm naming mine "Punisher", for obvious reasons. Hull will be painted matt black with the skull painted in white. I combined "rumpf3" and "rumpf4" in TinkerCad to make assembly and printing easier. Still working on the rest of the boat. Printing it in eSun ABS+ on an Ender 3.

looks awesome :)

where can i find BOM for this?
specialy type of brushless motor You used :)

there is no BOM yet.
and for the motor i used a 1:8 scale motor. little over powered but fun

Hello, I printed a 70% size version but I'm having issues with the propeller not being able to pull water, should the "bars" under the boat on the inlet be removed after printing?

hi, no the bars are there to keep dirt and leafs out of the tunnel.
Is you propeller turning the right direction?

Hi, how did you print the Romp1? i am using cura program and the ender 3 pro printer with a .4mm nozzle.

hi, i printed several boats, most of them on a prusa i3 mk2. I used a .4mm nozzle and 0.2 mm layer hight. some of the parts you still need to orientate properly. i will do this if the files are final.

Which way should the impeller go on? At the center where the shaft goes through one end of the impeller is thicker than the other end. Which end should be toward the back of the boat?

hi, the bigger diameter goes to the back

So, Im a bit new to the motor's that are talked about. I have a spare 540 3000kv motor sitting around Im not to worried about speed. But just wanted to know if would fit it to the current mounts.

Also wanted to know about the M3 bolt Version's?? ( I have zero M4's -lol-)

if you are not sure if the motor fits, print the first couple of layers from the hull part that has the motor mountings. there are 3 different mounting hole pairs. one of them should fit.

Hey Just wondering if I should take the guard/supports at the bottom out because I was wondering if they were a guard so no junk gets in thanks

Yes these are supposed to keep dirt out of the propeller tunnel. because leaves can get stuck there easily. but i need to improve them, because ours broke easily.

So I've got it almost fully constructed

My biggest problem is that my propeller vibrates, it's fine at low rpm but in the medium range it makes a lot of noise and rattles

If I quickly flick the stick to make it go super fast then it balances out and I can rev up and down decently without any wobble

Any way to fix this?

try the new nozzle, maybe this will help.

can someone take a picture so i can see the propeller is attached

  • Posted with 3D Geeks Thingiverse Browser App

Check out the make from 3dkaki. he did it with a dog drive adapter. Should work quite well. Otherwise you could just glue it on the shaft if you don't have that big of a motor.

Here is a short driving movie with my setup


NTM Prop Outrunner 750kv at 3s
tomorow i will try it 4s. but the needed current is amazing.

And here is the test with 4s. it is definetly a bit faster.


Works really nice. Thanks for sharing

so everything went good so far but i am having a problem finding a shaft. i need some help. could you throw up a link to the shaft that works with this build please? i appreciate all your help! can't wait to take her out on the water! :)

hi, you will need a 4mm shaft with at least 170mm. best would be one from V2A material or anything else that wount rust.

also how do i keep the propeller from spinning on the shaft?

  • Posted with 3D Geeks Thingiverse Browser App

can someone show how to connect the propeller?

  • Posted with 3D Geeks Thingiverse Browser App

I have a big printer, do you happen to have a 'all in one' boat file (ofc with top off to fit parts in). Ideally one where the inner holders could be glued in so that it doesnt need supports. Thanks in advance.

Is here someone with a driving movie?
I love the design the fuselage is ready now. Next step is the electric

  • Posted with 3D Geeks Thingiverse Browser App

Can you please list the parts that you have used

I am completely new to RC Boats

What servo do I need? What length of shaft do I need?

Comments deleted.

it printed perfectly for me using robo3dr plus. i use three parameters and 15% infill as suggested it floats really well and sealed tight.

ok it printed well and glued together nice and tight. now as for the motor. my motor wont line up all 4 screws so could you give me the link to the motor you used here? and screw size and length also for that motor. also where can i find a shaft with the pivot joint like yours? thanks looking good so far!

Hi tommy, there are two pairs of motor mounting screws. I think one is 19mm distance and the other is 21mm. So use one two screws that fit your motor.
The screw length is motor specific. But for m3 you should screw them about 4mm into the motor. So length should be 12mm overall.
Right now we already printed 5 of the boats including a 50% mini version. I hope we find the time to build them soon, and then I can give a recommendation for the components.

thanks. so 19 or 20mm did you grind them down to 12mm then? and is this info for the full scale? that's the one i ended up printing was full scale. i just need to set it up now , thanks im looking forward to this summer with this jet boat!

if i print it at 70% as i saw it has been then what motor do i use? getting ready to print but i bought pla because my printer heat bed went out. it prints well but will it work? i loaded the back and it said it would be 30 hours to print thus i was considering 70%. hey also i need to know what to print this at. how many parameters and what infill to use? how many parameters will it take to not leak? and does it get 100% infill or 20% how much is needed to float well? i have two rolls ready to print 240 hours just for this body lol.

i used 15% infill and 3 outlines and then it was watertight

thanks i am starting today. guess i will do the 100% since i bought 2 rolls for this anyway. hope pla will be fine thats what i have so wish me luck lol. i will let you know when its done. :)

Thanks for sharing your nice model Bash :)

I printed my first in 70% and it just a great model to assemble and use.
Everything fits just fine after scaling it, only post print work really needed apart from gluing together was to widen the motor mount holes abd the bearing holes. All screw holes apart from the outer nozzle also had a perfect fit and are self threading perfect. This with different screw dimentions.ofcourse.

70% size will be perfect with:
-- 4x 3x25mm - screw for jet drive
-- 2x 3x6x2,5mm - prop shaft bearings
-- 6x 2x6mm - screws for the lid
-- 2x 3x10mm - screws for steering nozzle (2-3mm shorter would probably be better)
-- 1x 3mm - prop shaf (forgot to meassure length)

have fun, i did :)

Hi larumba,
we did a test with a 50% hull and it worked quite good, 2mm shaft and instead of the M4 screw we used M2. unfortunately I have very little time right now, but when its finished I will post some fotos.

Can you give a recommendation for the hardware for the 50% Version? With a 2mm shaft perhaps a 17 g A1510 outrunner could be used? Like this one: https://www.premium-modellbau.de/17g-brushless-aussenlaeufer-motor-a1510-2200kv-quadcopter

Thank you!

Hi just finished printing how long is the drive shaft at what position is the prop in the boat thanks

Hi, the shaft depends on your Motor shaft and coupling. but its roughly 170mm.

Hi. First of all, Great JoB Dude, ur Thing is now in Print.
I used Ur Top 4 my Remix. Really Nice!!!

But one question. Bearing. u really mean ( 8 outter dia and 4mm inner dia?) i dont find this combination.

best reg.


Hi Chop,
yes the measures are right. I tokk them because I had them on hand.
What diameter do you want to use? Because I can quickly update the model.

But i Had a Wish ;)

Can U Bring two of them :

To the nozzle? I need Something to Cool the ESC i need 5mm outter Dia.

Would be Nice

Yes shure. M4 treads?

M3 pls. U will Design a hole to screw them in oder um will Design the hole nozzle to the nozzle? I think the second Option would be better or?

Yeah sure go for it

Hi. Ty 4 the quick Response. Argh .too late. Back ist in Print :/ but okay If this is the correct measure i will find them ...

I build with 3660 3300kv and 120-200a ESC. I think this Wil Work great on 4s. What do U think?

Bearing i find only 8mm outter and 3 inner Diameter

Hi. Ty 4 the quick Response. Argh .too late. Back ist in Print :/ but okay If this is the correct measure i will find them ...

I build with 3660 3300kv and 120-200a ESC. I think this Wil Work great on 4s. What do U think?

Bearing i find only 8mm outter and 3 inner Diameter

thats a quite strong setup. You will have a lot of fun :). maybe you can post a video. Because I m planing on doing a way more powerful setup aswell.

I will!

So whats Ur Plan?

I was thinking of a setup from a 1:8 buggy on 6s. Massive overkill

Oh yes... It will bounce All over the water

Any advise on RC parts ? I'm new to RC hobby and not familiar with the 'language' innerrunner, outerrunner doesn't ring a bell.
Some help on RC related parts (links what to order) would be fine!

Hi Thijs74,
i will build a couple more of these boats since we want to race them. Then i will post what components i used from hobby king.
but basically for the components its quite easy, you ne any Remote Contol. You need a Servo in standrd size. A motor tha has mounting holes with 19mm distance and a Battery.
But I will update the discription soon.

Great ! Have an account at Hobby King so will make live easier.
Will be following the comments on your nice design, Chopdi is asking some nice questions in respect of cooling the ESC (looked it up to confirm it's the speed control ;-)) ) etc.

Thanks for sharing your design !


Hi. Yeah. Its the Speed Controller.

so i really like the boat and i was wondering what size lipo to use and more really where does it go? do i mount it in the rear i see a vacant place or the front under the dash? i'd really like to see how well it goes if you can upload some video any length no rush it is winter i know. super kool jet boat! better start thinkin of a name lol.

Hi Tommy, on the left next to the jet i put velcro strap to put the battery on. And a video is in the making.
And yes , we need a good name for the boat. any suggestions?

good place i think also for the lipo. as for the name i have a few. maybe the rapids basher, or little ripper, or like ziggy or drift king or proto rrp1 river rapids pro 1. or you could go old school names like rolling thunder, silver fox, high octane! all decent name for this boat imho. cant wait to see it go. i have to get a new roll of filament first to print this one.


Very nice project and design i must say. Bash, if you got time there is a few changes i will recommend to make the
assembly easier and the back jet assembly and also the part where the jet assembly mounts to the body.
Over all very strong and neat. I'm about 80% done and will post some pictures of the final boat.

Thank you

Thank you for uploading this great design! I was wondering whether the general shape of the boat and of the jet would still work when being scaled down. I have some very small streams in my area and a jet boat of about 25 cm length would be perfect for them. I think I will give it a try.

Hi Bash,
very nice Job, i printed it on my I3 Plus with PLA, after glueing the Piece together i reinforced all the hull with epoxy+glass fiber, really strong now. I did the connection between the shaft and the Propeller with a M4 nut screwed on the treaded shaft, very strong too.
I have a question about the motor size i have to mount, i think a brushless with 4 cells will be enough, can you tell me what you mount?
Best thanks

Awesome, can't wait to see another one in action. We used a 480 size inrunner with 3s. But it got very hot. So 4s and a outrunner will work very well.
Keep me updated

Thanks for the Feedback! Whick glue did you use?

I printed the boat in petg and used regular super glue. and to get the little gaps closed between the barts, i sanded the hull a little bit and the sawdust covered the gaps. then I sealed them with super glue

Hi, how Do you plan to realize the connection between the shaft and the Propeller?
Cheers Benjamin

Hi Benjamin,
this depends on the power you put into this. it is designed as a pressfit. but if you have a strong motor its the best way to heat the shaft and then press the propeller on it. it worked really well for me.

nice boat! did it all print well and fit together perfectly or does it need work to fit it together? looks like a great design i really like the jet intake directly printed into the boat i had also thought to do the same thing. why make more pieces to glue on if it will print as one unit right. that i would think would make it much stronger and and smooth water flow. i would like to see how well it floats the weight when it is fully loaded. and how well it goes through the water. great job!

Hey Tommy, thank you.
Yes it printed very well with petg. but you need a well calibrated printer because the tolerances are tight. But then it will click nicely together.
Then i applied glue and it was watertight. I think i will end building it by next weekend and post some pictures then.