QE2 is the first passenger ship to use Grim Wheels (so called because they were invented by Dr Ing Otto Grim) in an attempt to make the new QE2 even more efficient. These wheels spin freely in the wake of the main propellers. The innermost parts of each of the 7 blades pick up speed from the propeller, while the outermost parts act as propellers themselves, adding some forward motion to the ship for "free", capturing energy which would otherwise be wasted. The Grim Wheels are 6.7 meters in diameter.
This set up worked very well and added two or three knots until, that is the blades started to fall off during or soon after trials, the rest were removed soon afterwards. It was indeed, a grim time for Dr. Grim.
LB