With things not looking good, it was time to spend a bit more money. First, a new prop - something in red this time because red things go faster. Also, slightly smaller than the old propeller and without the hasty scissor modifications.
While I was at it, the rudder support box has been opened up properly both at the back and sides. Much neater, no longer will it work as a parachute. I've also shortened the rudder as there's no need for it to be lower than the bottom of the prop and I reckoned it might be increasing drag. Yes, I am a bit desperate.
Next, some weight loss. The C-cell battery pack has been replaced with an AA-cell one which weighs half as much. Moving it to the front of the battery box moves the centre of gravity forward too.
Back at the lake, does any of this make a difference?
Not really. The boat moves but once underway, the prop is still thrashing around in a void created by the hull. Hang on to it and with plenty of water, the thing really pulls. Let go and it's a bit rubbish.
Once thing, I've never, ever seen one of these kits made up. I'm beginning to understand why.