Mike,
BUT - The trim tab cannot be turned so the leading edge turns to the right .....
The manual states "turn the rear of the trim tab to the direction of the pull".
( I am presuming the rear of the tab is the trailing edge ).
Given that the trim tab cannot be physically turned the other way I shall try as the manual states. I don't think it does behave like a rudder, it is a little aerofoil shape. ( Hence Dick - AlderneyBassman's "weird physics" ).
Duncan,
I agree with what you are saying and I need to get some weight on the boat moved forward somehow but I apart from the batteries ther is nothing else to move.
I will report back with findings after Saturday's trials !