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[Terry]

Hi all, my winter project is a Caldercraft Joffre, not arrived from Blighty yet, but I am already thinking about one of these to power it. Any comments welcome.
http://www.mtroniks.net/prod/Boat-Speed-Controls/G2-Hydra30-System.htm

[Neil]

I don't know  anything about brushless motors except that they can rev very highly............but I wouldn't hae thought that revs were needed on an old steam tug..........a 3 quid 385 motor and 15 amp speed controller would be ample for the Joffre.....sailed my puffer.......equal size for years on one. neil.

[Shipmate60]

The last one I fitted out I used a low drain 545 motor on 6 volts.
As Neil said cheap.


Bob

[Calimero]

Hi all, my winter project is a Caldercraft Joffre, not arrived from Blighty yet, but I am already thinking about one of these to power it. Any comments welcome.
http://www.mtroniks.net/prod/Boat-Speed-Controls/G2-Hydra30-System.htm

What's the prop diameter on that tug ?


50mm I assume ?


Even under 6V that 1000kv motor would be too fast. For a 50mm prop on a tug, shaft rpm should be around 3500, tops. On a steam tug you could probably go down to 3000 rpm. That would be a 500kv motor under 6V.


My next twin screw springer with 48-50mm props (in Korts) will get two 620kv motors under 6V but I intend to do some heavy towing ...

[Shipmate60]

Or use a smaller or less pitch prop.
These smaller models can be powered quire successfully on 3 blade plastic props.


Bob

[oldiron]

In my Joffre, I used a Decaperm I had sitting on the shelf. Plenty of power:
http://www.modelboatmayhem.co.uk/forum/index.php/topic,42151.0.html

John

[Subculture]

Decaperm doea bout 3kRPM unloaded doesn't it?

So if going brushless you would want a low kv set-up, about 500kv for a 6 volt system and 250kv for a 12 volt.

[Geoff C]

Hi,     I'm going to power my 36in. tug Empire Raymond with an Mtroniks M500 motor, a 6volt 4amp SLA battery, an Mtroniks Marine 15 ESC, all driving a 65mm three blade plastic prop.

[nick_75au]

The motor in the OP will drive a 50 mm prop at 6 volts but is a bit fast, A hobby Kink DT700 will work really well, its 700 Kv but in a bell motor rater than an oversized outrunner that usually has the low Kvs, the other option is some of the newer multi rotor motors are getting down in Kv whilst not being 3000 watt monssters


http://www.hobbyking.com/hobbyking/store/__6246__hexTronik_DT700_Brushless_Outrunner_700kv.html


http://www.hobbyking.com/hobbyking/store/__41623__4108_380KV_Turnigy_Multistar_22_Pole_Brushless_Multi_Rotor_Motor_With_Extra_Long_Leads.html

[Geoff C]

The Mtroniks M500 motor, 4.8 - 13volts   16000revs at 12volts