Originally Posted by Poly
I had a Quicksilver variable pitch prop years ago on my old 5.0 litre v8 Bayliner. It looked exactly like these.
It had an adjustable disk in the centre which loaded a spring on some centrifugal weights. Once the prop was spinning fast enough and the water pressure reduced on the blades the weight would jump over a cam which pushed the blades pitch up about 4 inches.
It was great for pulling up skiers and rapid hole shot. Once the boat got to about 15 knots it would change pitch and the engine revs would drop.
Sounded just like an automatic car changing from 1st to 2nd gear.
If I slowed down and hit the throttle it would shift down again.
Was good but v heavy. I used to be so nervous of hitting something in the water. That much weight spinning hitting a log would explode the gearbox and wreck the prop.