Help! Boats? (I know this is a plane forum)

[OlliePackman]

I know we all fly planes here (and this is in the fun and distractions category) and no one might be able to help me but might as well put the questions out there...

My plan is to build an RC boat out of the spare components that I have from crashed and unwanted planes just as something a bit different. There are some things that are different, but from my understanding, the systems are largely the same. With regards to an actual body/Hull (Airframe for plane people 😂) I am going to use replacement parts to an existing product which you can find in the next link. Please make note of size, weight etc. For the power system.
Hull - https://m.banggood.com/FT012-2_4G-B...-gb-en-mb¤cy=GBP&cur_warehouse=CN&createTmp=1

Canopy - https://m.banggood.com/FT012-2_4G-B...-gb-en-mb¤cy=GBP&cur_warehouse=CN&createTmp=1

For power, I want to use a 16mm jet thruster (or 2 if possible) found below along with a 2440 4000kv motor (also found below) and a 50a hobby wing skywalker ESC which I already have. If it is only possible to use one motor per ESC (?), then I will have one central jet thruster providing it will produce enough thrust to get a decent speed out of the boat considering size and weight (?). However, if there is some wizardry which I don't know about which means that you can use 2 motors (powering the jet thrusters) off of 1 ESC, then I will do this for increased thrust and speed. Not sure how much sense that all makes so I guess my power questions are:
Is the motor the right size for the jet thruster?
Is the jet thruster the right size for the boat?
Can you power two motors off of one esc?
Would you advise having one or two jet thrusters?

Jet thruster(s) - https://uk-m.banggood.com/1pc-16mm-...y=GBP&cur_warehouse=CN&createTmp=1&ID=6157193

Motor(s) (4000Kv version) - https://m.banggood.com/Racerstar-24...nnel&utm_campaign=Feb&utm_content=huangwenjie

ESC (which I already have but might need another if I need 2 jet thrusters) - https://m.banggood.com/Hobbywing-Sk...6ia4VUVh8F9g3HBMscToEdY8o85D1gPcaAg4XEALw_wcB

Also, I'm pretty sure I am limited to a 3s setup as the jet thruster says it is only rated for 6 - 12V (please confirm) so what 3s battery should I use? I'm thinking 2200mah 30C but I have 3200mah as well if needed - please advise.

I will be using a 9 gram servo for thrust vectoring and the rubber seals for the control linkage so water doesn't leak in. Also, the esc won't have air to cool it anymore as it isn't in a plane, so I was thinking of improvising a water cooling system with fuel pipe wrapped around the esc.

Finally, if there is anything else that I have missed then please point it out to me and thankyou for reading this giant thread and checking my stuff out. Much appreciated.

 

[Morgajus]

I'm interested if you've continued this project. Particularly how you cooled the brushless escs.

I used brushed motors and a single esc for mine. Never thought to try retrofitting a plastic hull, I used balsa and 3mm plywood (It doesn't seal well at all...)

The only advice I could glean from my attempt would be to be VERY carful about your weight distribution. I put my RX up on the side wall, which caused my flat bottom boat to list hard to the left. Though, it tracked a lot better while listing...

 

[Matthewdupreez]

I made a sail boat from FB...
Hull 86cm
View attachment DSC_0119.JPG

 

[Tench745]

I know we all fly planes here (and this is in the fun and distractions category) and no one might be able to help me but might as well put the questions out there...

My plan is to build an RC boat out of the spare components that I have from crashed and unwanted planes just as something a bit different. There are some things that are different, but from my understanding, the systems are largely the same. With regards to an actual body/Hull (Airframe for plane people 😂) I am going to use replacement parts to an existing product which you can find in the next link. Please make note of size, weight etc. For the power system.
Hull - https://m.banggood.com/FT012-2_4G-B...-gb-en-mb¤cy=GBP&cur_warehouse=CN&createTmp=1

Canopy - https://m.banggood.com/FT012-2_4G-B...-gb-en-mb¤cy=GBP&cur_warehouse=CN&createTmp=1

For power, I want to use a 16mm jet thruster (or 2 if possible) found below along with a 2440 4000kv motor (also found below) and a 50a hobby wing skywalker ESC which I already have. If it is only possible to use one motor per ESC (?), then I will have one central jet thruster providing it will produce enough thrust to get a decent speed out of the boat considering size and weight (?). However, if there is some wizardry which I don't know about which means that you can use 2 motors (powering the jet thrusters) off of 1 ESC, then I will do this for increased thrust and speed. Not sure how much sense that all makes so I guess my power questions are:
Is the motor the right size for the jet thruster?
Is the jet thruster the right size for the boat?
Can you power two motors off of one esc?
Would you advise having one or two jet thrusters?

Jet thruster(s) - https://uk-m.banggood.com/1pc-16mm-...y=GBP&cur_warehouse=CN&createTmp=1&ID=6157193

Motor(s) (4000Kv version) - https://m.banggood.com/Racerstar-24...nnel&utm_campaign=Feb&utm_content=huangwenjie

ESC (which I already have but might need another if I need 2 jet thrusters) - https://m.banggood.com/Hobbywing-Sk...6ia4VUVh8F9g3HBMscToEdY8o85D1gPcaAg4XEALw_wcB

Also, I'm pretty sure I am limited to a 3s setup as the jet thruster says it is only rated for 6 - 12V (please confirm) so what 3s battery should I use? I'm thinking 2200mah 30C but I have 3200mah as well if needed - please advise.

I will be using a 9 gram servo for thrust vectoring and the rubber seals for the control linkage so water doesn't leak in. Also, the esc won't have air to cool it anymore as it isn't in a plane, so I was thinking of improvising a water cooling system with fuel pipe wrapped around the esc.

Finally, if there is anything else that I have missed then please point it out to me and thankyou for reading this giant thread and checking my stuff out. Much appreciated.

Not sure how I missed this one back when you first posted it.

The jet assembly shouldn't care two whits about what voltage you run. It's just a plastic housing with a propeller inside. The motor you choose will be the limiting factor for what voltage you can run. I don't know much about sizing jet drives, so I can't tell you if it's the right size for the boat or not. If you want reverse, you'll probably have to add a reversing gate to the jet drive somehow.
That motor you specified has the wrong diameter shaft. The jet says it takes a 3mm driveshaft and the motor only has a 2.3mm shaft. You could probably make it work with a sleeve around the shaft to make up the difference.

Like I said before, You'll need 2 ESCs to run 2 brushless motors. It doesn't look like there is much space to put two jet drives where the intake will stay in the water on that hull, so you may be limited to just the one on the centerline. That said, more power is always more fun,so why not run two if you can fit them? You will have to be mindful of your weight though. If it's too light the boat will float too high in the water and get bounced around and capsize easily. But you also don't want to over-load it and have it perform like a pig, or sink.

As I understand it, most RC boats of that size don't run the motor and ESC hard enough to get super hot before you have to swap out the battery anyway. So, you can just run it air cooled and let it cool off when you swap out the battery. This may change for your specific setup, so you'll have to see how it goes. I wouldn't add the complexity of water cooling unless you find the ESC or motor actually needs it.