Having since run a series of basin trials (paddling pool) she was indeed lively, frighteningly so. So I decided to add more weight comprising four torpedo fishing weights placed as far apart athwartships as possible, with the longitudinal axis of the weights fore and aft and as low down as possible, placement fore and aft was by trial and error in the bath. The placement athwartships did the trick and she is now very stable. The weight I added was about 550 gms. She floated a bit lower but not as much as I expected, not enough to warrant repainting the boot topping. Then I realised why I had the problem in the first place. As a single screw ship all the weight, motor, battery, rc battery and receiver, esc were all on the centreline, there was very little athwarship stability. Placing the new weights athwartships as I did rectified the problem.

So for all beginners, when ballasting your boat consider weight distribution not only to get the boat down to the waterline evenly, but for longitudinal and athwartship stability. I should have known that from the beginning as my college qualifications are in Naval Architecture concentrating on warships, but that was 40 years ago. A lesson relearnt!