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

RC Jet boat experimental pieces

by Superclodbuster Sep 9, 2019
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Hey everyone,

Latest test video is up at https://youtu.be/Y-EhzNfpUQY

Was only around 80% throttle

Esc is a 200amp
Motor is a 3674 2600kv
3s 5000mah

Would definitely use a lower kv motor for this voltage

Overall great easy project , will post my make on the weekend and upload a video on my channel for you guys to check out.

Thanks everyone


Going too try a few things from the rc groups forums, there's an impeller, stator and nozzle that I think may work very well, once I've done some testing I'll report back with my findings, welcome to add them if they work out


i read through the threads on rcgroups. i can also mirror the existing props that will make them left handed.
i see sundogz posted a solution that i can also adapt to fit existing.
let me know what you find to augment or modify existing .

Hey mate,

So last night I grabbed the fdj 35mm v2 drive and modified the stator/nozzle section from 35mm to 40mm and added the hull mounting location to it, I reworked the 35mm steering nozzle to suit the steering arm we already have, have printed it all out, sundogz also uploaded a 40mm variant of the impeller this morning so will print that this afternoon, hopefully should be able to get some testing done later in the week, I would be really happy if I could get my hands on an ampmeter to see what draw it has after the changes, if it all works properly it should just be a simple reprint of the impeller and nozzle components and screw them on

added 3 more props, sundogz version and i turned the original 4 and 3 blades into left hand threads.

so there are 5 props for testing 3 and 4 blade, sundogz, and 3 and 4 blade left handed.

Might be worth having a look at https://www.rcgroups.com/forums/showthread.php?2826297-FJD-3D-printable-Jet-Drives/page64

Post number #954 the gen2 35mm jet drive, the stator design is pretty cool, this is the one ive modified if you can pm me your email i can send you the stls this afternoon (830Am Here) to have a look over

i sent you a pm message. the simpler the fix the better. i posted his reworked prop in the files for the boat.

awesome thanks mate

Well, I ended up with a 200a esc and 4074 2600kv ran it on 3s and it bloody flies, had range issues yesterday and had to retrieve it then it was dark, did some more testing this afternoon and smoked the caps on the esc before I went through a battery :( by chance are you able to tell me the pitch of the impeller? I've done a bunch of research and for the higher kv around a 17 degree pitch would be ideal and maybe even go to 3 blade, I will post my video on YouTube and link it hopefully tomorrow, thanks for all the effort everyone has put it, it's a good design

added a 3 blade experimental prop. pitch is the same as original the blades are just reduced from 4 to 3.

Thanks mate your a legend will give it a try I'll report back, if it's not too much hassle would you be able to make it a 2 blade aswell?

no idea but you can make your own prop from the STL files.

i decided to lower the amp draw by going with a 2S Lipo. like i mentioned the boat flies. so lower voltage was just fine for me.

smoking caps on these seems to be the norm as the caps are not water cooled. lots of boats on various websites had esc fires.

i got stuck unable to test more as the season ended. took me a month to build my boat between getting parts and redesigning the STLS so i started in August. got the first test in September then ordered new parts and started a new print couldn't get everything before october so was closed out by the fall/winter

Hopefully purchasing the motor and speed controller today, just thought I'd voice my opinion on the motor choice for this boat, after spending a bit of time researching and talking with my local hobby shop the motor chosen for this boat may actually not be the best choice, for a 40mm jet drive the rpm limit should end up around 25k and then work on the impeller design if it doesn't perform from there, I think the 60k rpm of the current motor maybe why the high amp draw and killing the esc that you used the first time, the proboat river jet uses a 34mm impeller and a 2300kv motor with 90amp speedy, so I would think something around that would be perfect for this also, We shall see, I'll report back tomorrow if I get it running tonight

Thanks everyone

for me the original speed controller and motor combination was at the time the only cheap made in china packaged water cooled motor and boat ESC available.

it was a 70amp rating. the original design by Bashtech is also still experimental and went though 2 different nozzles as there was already issues with amp draw. the second nozzle design is more open then the original. i only made slight changes to the nozzle to beef it up in a few areas but did not touch the internal surface area of the design.

many people reported issues with the water cooled ESC i bought, mine smoked after a few runs from the capacitors. i changed over to a more expensive 120Amp esc with a better design. i then also beefed up the batteries. again everyone is using whatever they want for the power source. the design i released is just a fix up of the BASHTECH design on a remix.

BASH_TECH's original design does not have water cooling so you were more limited.

good luck :D

Anybody have any photos of how to set the impeller up?


everyone uses different materials and setup, but this is how i setup mine with amazon purchased links.

you have to customize and fabricate as needed.

Just looking around online, can buy a 40mm ally impeller quite cheap if need be also, I'm comparing this build with a friend's proboat river jet and that uses a much smaller motor and pump but is a lighter boat would this be comparable in speed?

Also noticed that the impeller has 4 blades on this print and the aftermarket ones are 2 blade or 3 blade, maybe why the high amp draw?

Just finished assembling the 4 hull sections and sanded ready for a coat of polyester resin, and had a thought regarding your mention of moving the intake forward, would it be possible to design another rear section? As in an extension piece that attaches to the rear hull section? Could be a totally sealed section around 80mm long, obviously would then require another drive shaft though....Just a thought lol

Thanks for your efforts, I will post my make next week once I've finished painting

Hi, love your work with the modifications mate looks great, I'm in the middle of printing this now is there a video anywhere of this running? Might be printing another 2 for friends and they are really curious of how it goes,

Thank mate keep up the great work.....Merry Christmas all!!!

found the old video

this is the yellow MK.1 boat before all the new revisions for the white and red boat MK.2

i had a really low res video up for a little while.
i used mine in a large swimming pool.

with the power setup i used it was very quick, it disturbed the water inside the pool very quickly so you had to feather the throttle because if you came out of the water the intake would suck air and then it took a few seconds for pressure to build back up in the prop tunnel.

it was surprisingly responsive to steering controls at one point i was doing figure 8s around 2 people standing in the shallow area of the pool.

i was able to make 3 runs with the boat power lasted about 15 minutes per run.

these were the runs i did before i posted all the redesigned stls. As i learned from the problems i had with the original version.
the season ended for the fall before i was ready for more testing. i have done small scale testing in the bathtub and in a small puddle of a pond near me since.

this was why i feel the project isn't complete yet. moving the the intake forward on the haul would also help keep the tunnel full of water.

i placed a front ballast to help hold the nose of the boat down to compensate. you will need a ballast on the right rear to counteract your battery on the left side as well.

one lesson i learned from these runs were do not use bearings for the prop shaft use bushings. the pool chlorine ate the bearings.

depending on your running gear the internal temps even with water cooling will be enough to soften PLA for the new version of the boat i installed water proof heat shielding on some parts.

eventually after i got the design problems worked out i was going to print the haul and deck lid from ASA.

Ahh yep that's ok, sounds like it should go quite well then, will the modified rear hull section be interchangeable with the motor mount section?

all my stls are compatible together. it won't be compatible with the original version of this boat from BASH_TECH because i changed the lip for the upper deck for the rubber seal. and how the sections interlock together slightly.

as for the future. if i move the prop tunnel forward then it would require extensive reprints because i might have to move the motor mount forwards to make clearance and thus you would need a longer shaft and possibly this would mean the prop tunnel has to go into a 3rd section of haul to work.

I started this project. is fantastic. where can I find a complete and updated list of electronics? I live in Italy, can you find everything on banggood?

i don't use banggood but i assume you can find them.
i used a:
ESC: Dynamite 120A BL Marine ESC 2-6S Single Connector, DYNM3876

Motor: MagiDeal 2598 4200KV Brushless Motor & Waterproof 70A ESC Combo for 600-800mm RC Boat. This came with a 70Amp ESC which overloaded so i went to the 120A Dynamite ESC with the 2598 motor.

the battery i went to a: GNB RC Battery 7.6V 5600mAh Shorty 2S LiPo LiHV Battery 100C 4.0mm Bullet Deans/T Plug, Shorty 2S LiPo for RC Car 1/10 Scale Vehicles
the boat pulls a lot of amperage so the 65C Lipo i tried almost exploded. i went from 65C with 130C Burst to 100C with 200C burst.

you can go bigger on the battery but it was fast on a 2S lipo.

right now testing is closed for the year due to winter.

I have printed Middle_Haul_2_V1.5 and Motor_holder_Haul_3_V1.5 but cannot get them to join up There is a clash around the are of the deck opening where the rim has been thickened up. ??

i didn't have an issue the fit was extremely tight and i had to clean a little elephant foot from the print. i looked at the thingiverse previews and they look correct. when i fit mine i had to hammer them together the first time to mock up the fitment after that they fit together but again it was extremely tight which is what i wanted.

can you take a picture of the problem?

ok updated the error new part is "Middle_Haul_2_V1.6.stl"
this fixes the joint error
you just need to reprint the new part and it will match to the other haul sections.
Let me know if you still have any problems.
here is my test piece.

First thanks, i found what happened.

when i intergrated the STEP files to replace my STLs it messed up that area of the haul and fusion 360 reported it was fine when i was completely wrong. i'm working on it.

Thanks Fits fine now.

found a minor issue not with the boat. thingiverse screwed up the upload of my files. the gasket for the boat was missing i uploaded a complete file for it so you can cut out the pattern from a rubber sheet.

I had noticed the gasket file was the wrong one but was waiting until I got to that stage before mentioning it.
I am now printing the final parts of the hull. I had an issue with layer shifting and have had to print at 50% speed - takes forever.

yeah even working 100% all the parts take 12-26 hours to print which is a pain. i have 4 printers but you are always at the mercy of the longest part to print.

i wish i never started the conversion to STEP files(i stopped half way) and just left my original mesh files it caused so many problems.

Comments deleted.

I am following this with great interest - very good work.
Looking forward to the files with the stuffing box included.