Finally got time to account my experiences building this great model.
Downloaded the plans of the Strongbow from the internet and then spent numerous nights translating from German to English.
Cut the frames and planked the hull and decking with balsa. should have used a thicker heavier planking for the hull as i ended up with 2.2 kg lead ballast in order to get the paddles in the correct depth.
The power train is a motor and gearbox assembly from a kids RC truck. Originally it ran at 7.8v so using a 6v sealed battery gives me a good 2 hours of operation.
It is a lovely model to sail and surprisingly powerful, but a little unresponsive to rudder input.
Paddles operate at 120 rpm full throttle with no splash and a beautiful bow wave.
Will be having a play with new design paddles and will modify the power train to mix in independent paddle wheel operation with rudder input.
Would like to post some video of the outcome