Welcome To RCu

If you have the Dumas Motors, then they should be fine. I think that most people avoid them purely on the basis of cost for "what it is". Dumas charges a bit for putting their lable on it.

A good Electronic Speed Control (ESC) will be a great improvement over the Dumas Mechanical speed control.[link=http://search.horizonhobby.com/index.jsp?D=esc&sid=117EADBF3E7F&Ntt=esc&N=763]Pro Boat[/link] offers two options, and [link=http://www.hobbypeople.net/guru/hps_1017601557.asp]Mtroniks[/link] Viper Marine(10, 15, and 40) is another brand of water proof ESC.
Of these two, I prefer the Mtroniks for scale ships, as they allow a lot of low rpm control. The Pro Boat jumps from fast to faster and seems designed for "go Fast" electric boats.

[link=http://www.modelcontrol.com/]Model Control Devices(MCD)[/link] and Vantec are also good marine ESC. Though the Vantec is subject to a "Frequency Feedback" through the motor. The feed back does not affect any running aspect of the boat, however there is a fairly loud "Whine" that reverberates out of the motors at low speed.

I have only a little experience with the Graupner Bow thruster and it is adequete for what it is.
It is limited to 6-7.2 volts, and complains loudly if run on a higher voltage. Not sure how the Robbe version of the bow thruster runs. But for low speed docking maneuvers or aligning a boat for pushing a load, the thruster can help get the boat in position quickly.

Post pictures of your Darby as you build. Everyone loves a good build up thread.
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