Project Flows' Giant waterwheel being lowered into position -
So go on then, how did we get that 1 metre diameter chain wheel sprocket on ?   (and no, the wheel wasnt lifted)
Onboard the  power train - very popular with dads - is about 1 to 200 step up BTW.

Thats the 12 volt Permanent Magnet (PM) alternator box in blue  
River view
Leaving Amble