Topic: Steering a twin engined boat

[Jeremy]

Not sure if this is the right area for this but I'm sure Colin will move it to the appropriate one if need be .

I have just bought a Deans Showgirl . Its the first time that I will have built a twin engined model. What is the best way to control the motors. I believe there are 3 options. 1] control both motors from 1 speed controller (does it then need double the capacity) 2] have 2 speed controllers each running on its own channel and so achieve tank steering or 3] use some kind of mixer to add rudder into the equation but only 2 channels. I believe that Ron is an exponent of the twin stick/tank steer theory which I have to say seems to be a simple set up. Not sure how easy it will be for a relaxing spin around the lake though? I have 5 channel radio so all options are open to me its whether I buy 1 or 2 speed controllers etc? Any comments would be appreciated.

[ship's doctor]

Hi Jeremy,

I've used the 'tank steering' method on quite a few models and I think it works very well, you soon get the hang of it! There are diagrams on the Action site for setting these systems up that I think have been posted recently. In terms of cost if you already have a multi channel radio then you don't need the extra investment of the mixer, which still needs two speed controllers to run.

James

[Jeremy]

Seems to make sense. I noticed that Action did a combined mixer and speed controller, but I think that would still be quite a bit more than just 2 controllers. I think I'll go with 2 Mtroniks and if I don't get on with it I can always add a mixer at a later date.

[colin]

Hi Jeremy,

i am sure this is in the right place for this thread... any thing to do with them there Ampie things this would be the right place..

my thoughts to the solution;

the Showgirl is a rather short Hull, and is classed as a motor boat, so the Hull is built for speed, and not really for manoeuvrability, if you was to turn a corner at speed with tank steering, the boat would likely roll over, also you have two rudders not far from the props, so it will be within its own rights rather manoeuvrable as it is, with out having to use tank steering or a mixer...

i would only use tank steering or a mixer if the boat/ship was not fitted with a bowthruster and/or over 3 feet long.

so if i was building the Showgirl, i would look in my box of bits, if i have lets say two 15amp speed controllers, i would use them but connected with a "Y" cable to one channel, or if i have a 40amp then i would use that ... yes of course, your max drain of one motor times 2 and add a little for safety..

if you do at one time build a larger model that has twin Props and only one Rudder, then i would defiantly recommend the P94 (ESC with built in mixer) from Action...

[Jeremy]

Thanks Colin. I'm all for saving money. I suppose it would be different if it was a tug or similar but as you say she is a Motor boat and in real life would not be expected to turn in her own length!!! I dont have any thing in the spares box so will have to buy something. I am assuming that both the props rotate in the same direction so the wiring should be pretty simple.

[Jeremy]

Another thought comes to mind. If I use 2 controllers what happens to the BEC supply. Would I have to loose the supply from one to save overloading the RX. Alternativly I could use non BEC controllers and have a separate supply. I dont think a little weight would be a great issue.

[colin]

Hi Jeremy,

to wire it up correctly with two ESC, and both ESC had BEC then yes you would have to lose one of the BEC supplies, for example removing the positive pin out of the receiver plug, and then masking tape it back onto the receiver wires, that way if you were ever to require the BEC from that ESC, you just put the pin back in the plug.

the props should run in different directions to get a better straight run ahead, there are experts around that will tell you Left should be counter clockwise and the Right should be clockwise, and of course the complete visa verse, with the showgirl i don't think it would mater which way you do it... so basically from the ESC one will be wired up Plus to the Plus of the motor, and the other would be the other way round (ESC plus to the negative of the motor)

same applies if your just using one ESC...

[swiftdoc]

Hello Colin,

is the direction seen from the motor or from behind the ship? In our club different opinions are found. I use two speed controllers with a "Y-wire" (one wire from the receiver splits up to two wires for each controller, so that you need only one channel).

Kind regards

Arno

[colin]

as seen from the stern of the ship....

and then theres the other decision which concerns two props one rudder, for better forward steering the props should turn onto the rudder, but this way is not so good for reversing...

in real life there were lots of tests made about clockwise and anti clockwise rotating props, wether on the right or left..... but this is not always the best way for the models... more of a trial and error sort of situation..

[Jeremy]

Thanks for all your advice. I think I'm going to go for 2 x15 amp controllers and then play with the options. If I use a y lead do I also need to remove one BEC supply?

[colin]

yes you do Jeremy, when using the "Y" lead, one of the ESC Plus pins must be removed from the ESC lead before being plugged into the "Y" lead.. 

[Jeremy]

Think Ive got it now

[Jeremy]

Just spoken to MTroniks and they sell a handy little gadget called a ZGM that you attach to one speed controller that cuts out its power supply without the need to play with plugs etc.

[colin]

one never stops learning, i have never heard of anything like that... sound like a handy gagit to have if running on two speed controlers that both have to ability to have BEC.