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[Darren]

Hello there I'm new here, I haven't done much in the rc boating world I'm just getting in to it, but I have a big back ground in rc car racing since I was about 5 up till last weekend due to stupidly high prices now well for my first boat I'm looking at a Robbe Katja, I notice people have stated it should b ran on 400 motor but I was wondering if any body has owned this kit and which motor they ran in it, I would prefer to run brushless than brushed but any help please as I'm struggling what to go for

[essex2visuvesi]

The katja will run fine on a brushless but the hull cant take corners as speed.

Im in the process of building a Katja for Katja (My stepdaughter), in Pink and Purple   

Initial tests last summer show that the 7.2V speed 400 on a 2S lipo (7.4V) is more than adequate

If you go for a brushless setup, you will probably want to upgrade the propshaft to a beefier one as the supplied one is a bit feeble. In fact on reflection I wished I had gone for an M3 or M3 propshaft when I built this one

[Darren]

I have just read that some people run these on 540 motors, I guess if u don't take the corner at speed it will be fine

[pompebled]

Hi Darren,

I've been playing around with a Katja hull some time ago (until it sank) and I agree with essex2visuvesi on the running attitude; the design isn't suitable for more than moderate power.

My experiments with a 540 motor on 6 Cells NiMH made that clear; when you make a turn at speed, the hull will turn into it like a motorcycle, but it will continue running on that side and bottom half, until you throttle down, which lets the boat tilt up again.

As I was conducting this test without the top half on, basically an open shell, you can imagine this behaviour was quite scary to watch...

I was testing home made ESC's at the time and some spray must have caused a short on the circuitboard, switching the ESC into full reverse.
The hull went under over the transom and the motor must have continued running for the remainder of the battery life, as divers could not find it in a 100m radius (on the sandy bottom they did find every bottle though).

Moral: use a closed hull with added buoyancy.

Regards, Jan.