Max-Prop Automatic Variable Pitch Propeller

Yet another intriguing bit of kit I sussed out in Annapolis is this new Max-Prop Ecowind propeller from PYI. As described to me by PYI's Fred Hutchinson, the prop has a spring in the hub that automatically varies the forward pitch of the blades as the load on the blades changes. By maintaining optimal pitch at all times, whatever the conditions, the prop is supremely efficient and maximizes boatspeed and range while decreasing fuel consumption.

As with any Max-Prop, the blades also feather automatically when your boat is sailing, thus decreasing drag and increasing boatspeed when the engine is switched off. Like other Max-Props, the Ecowind is also fully adjustable, though maximum pitch is set not by adjusting blade stops, but by changing the spring tension inside the hub. (Note that pitch is not variable in reverse.) According to Fred, the Ecowind can be removed from a prop shaft without being disassembled. Just pop off the hub zinc at the end of the unit, and you'll find a conventional shaft nut underneath. Routine servicing consists merely of hitting a few external grease points an annual basis.

One thing the Ecowind is not is cheap. Prop diameters range from 14 to 22 inches at prices from $4,800 to $5,600, about 40% more than what a conventional Max-Prop costs.

For coastal cruisers who struggle to get through one tank of fuel a season a fancy expensive prop like this may not make much sense. But for bluewater cruisers who burn a lot fuel motorsailing and need to maximize range as much as possible, this prop should more than pay for itself.