Never had a problem with direct drives. All of my boats have them. This 6 foot tanker is only driving a 2 inch prop and with the larger motor I recommended I don't see any problem. Just my opinion.
Lew
Florida, USA

Lew, the direct drive solution will put a strain on the motor whereas if he uses a 1:2 or 1:5 the strain is absorbed in the gears. This is why I don’t use direct drive in my tugboats. On a model of 6’ and swinging a 4 bladed wheel it is especially wise to use gearing in my opinion.

Helpfull insight. I always wondered how scale speed (like modeltrains) is converted to replicate
from the original

There is a very big difference between the speed (RPM) of a real prop and a model prop for ships. Even at a 1:50 ratio it will be too slow. A 1:1 should work fine, at most a 1:2 could be used. I would stick with a direct drive and control the speed with the RC electronics.
Lew
Florida, USA

Thanks for your comments and ESC advice, LewZ and RodC. Certainly very helpful.
I have had no prior experience with speed in relation to prop revolutions or size. The prop size is to scale 1:150. I realize the speed may be slow when I decided on the 90rpm but I took my guidance from the prop speed of abt. 110rpm of the original. I'll see once the model will go on trials. If too slow I probably will swap out to the 1:50 geared and run-on reduced throttle.

5cm diameter prop on a 6foot tanker? That is merely a 2" prop. At 90rpm there won't be much thrust

JockScott:

I found this among the specs on the motor you described. Technical data: Gear ratio 150:1; Voltage range 4.8 - 14.4V; Power consumption at 12V approx. 13,400 rpm, 2.95A at maximum efficiency.

So, it looks like your top speed (which will likely vary considerably with other factors) about 89RPM at 12V (about 1-1/2 revs per second). That's pretty slow barely moving, if at all for a 6 foot boat.

As for the ESC, the choice is yours, most "average" ESCs will handle the current, and most, but not all, will handle the voltage. Many ESCs will have options for F/B/R, some fixed, but many can be set by the user.

Check your thoughts on the need for a 1:150 geared motor to run your tanker. As I am strictly scale and not much need for speed I stick with the cheap-o brushed motors in the $5-15.00 (US) range .

You might look at this: RS775PH High Power DC Motor, DC 12V-24V 12,000 RPM @ 24V Large Torque Motor. This would be about 6,000 RPM @ 12V, probably a good choice for your tanker (direct drive, set motor limits on your transmitter). $16.99(US) on Amazon.

Lew
Florida, USA

https://www.amazon.com/Power-12V-24V-Torque-Bearing-Driver/dp/B086Z47DLJ/ref=asc

Not to derail any dialogue on a specific subject. To start, I am a total novice if it comes to RC operations.
I have bought the Krick MaxGear 1:150 motor V12 for my 6ft tanker project driving a 5cm Dia prop. I have been given a Futuba Transmitter/receiver running on 6V. What are my choices for an ESC for basic functions: variable speed forward/reverse? I would like to power the motor with a Lead/acid battery.

Thank you very much DG, for your response and availability.

I follow you because I like your contributions on various topics.

When I finish the model I'm updating you on, I wanted to activate a few more controls, provided that space and weight allow it, so I'll ask you some specific questions.
On the receiver I have five free channels that I would like to exploit in some way.
In the meantime I will be careful to understand as much as possible from your speeches and perhaps, as you say, from some video tutorials. On videos my problem is understanding English, because if it is written I can translate it calmly but if it is oral I have difficulty understanding everything. I should ask my son for help.

Alessandro, thanks for following me and I will help you whenever I am able...

Multi-channel RC transmitters of more that 4 channels generally have a stick, a slider or rotary control for each of the physical channels available.. When you get up to around 8 channels you can run out of room on the transmitter itself to control this capacity, so the remainder are assigned as 'virtual' or 'digital' channels. This means, the receiver may have a physical socket for a servo or switch for each of these channels, but these devices are controlled through a software function or 'mixer function' configured in the transmitter which 'blends' the motion of a number of channels together..

** (In an Sbus (serial bus) receiver setup, the SERVOS will be soft configured with a port address (channel number) and all connect to 1 socket on the receiver with a 'Daisy Chain' or data bus similar to PC USB hub device)

I hope this explains a little how all the channels can be controlled when you get beyond 4!

Multi-channel Transmitters have become very complex and are quite difficult to fully understand now. It generally takes quite a time to get to grips with them on a workbench with servos plugged into each port to help you visualise what you are doing to the config as you move all the sticks, sliders and knobs about... To further complicate the situation, many transmitters now have telemetry channels which read back some functions from the model to the transmitter and display this data in real time.....

There are many tutorials on these subjects online and I would suggest you take a look at the basic stuff first, maybe settle on one Manufacturer and work through a particular device within your budget. Another approach is to find out the most popular RC supplier in your local club and research just that one. Other members around you with the same kit will be invaluable during your learning curve.

DG