Why don't outboards/sterndrives have multiple gears?

[Simon666]

Originally Posted by Poly

gotchi - this should achieve something similar - but how big is your budget? Prices, Terms & Warranty

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.

[Dirk Diggler]

Originally Posted by kubcat

Old offshore race boats used two speed gearboxes, first gear was just to get on the plane as they were quite heavy especially with fuel when taking off and the used to run the props quite high.

Multi speed gearboxes were quite common in Class 1 until they banned them about 12 or so years ago. They were semi auto, with as many as 6 speeds, computer controlled!

[Dirk Diggler]

Torque Shift Propeller Exchange

These were pretty good, had one on a 225 merc for skiing