I agree with Brian60 that the motor rated at 17000 rpm is not well suited for this projekt.
Instead I used the no name option rated at 3V 10000 rpm.
I've tried the motors in two configurations.
The first configuration with one esc controlling both motors.
A video with this configuration can be seen here.
https://www.youtube.com/watch?v=4ymHigkdKt0&t=55sIt works ok, but the steering ability does not seem to good.
It's hard to turn the tug around in a simgle arch without touching the banks of the pond.
The second configuration utilizes the p82 w-tail mixer from action.
http://www.action-electronics.co.uk/pdfs/P82.pdfThis setup has a dedicated esc for each motor.
It can be seen here.
https://www.youtube.com/watch?v=WHRA70MtYQk&t=15sNow it's possible to turn the tug on the spot.
Only concern is is that the mixer seems to accelrate the tug when a turn is attempted at low speed.