The Ultimate Cruising Propeller
The Autoprop is the only fully automatic self-pitching propeller on the market and has been available now for over 21+ years. It’s concept was developed during WWll to improve the performance of landing craft in both forward and reverse and give maximum thrust efficiency at all rpm and engine loading. The propeller is the performance leader throughout Europe and the USA as the total propulsion solution for cruising yachts.
The Autoprop is an automatically self-pitching feathering propeller which varies its pitch depending on the operating conditions, thus maintaining maximum efficiency at all times. It has a higher efficiency over a wider range of rpm settings than any other type of propeller, therefore producing higher speeds throughout your engine’s speed range, allowing lower engine rpm’s, giving greater cruising ranges and fuel economy and quieter cruising. The blades automatically adjust their pitch to match the engine torque to the varying load conditions.
The Autoprop has the Identical blade shape in forward or reverse and therefore gives more control for backing or maneuvering due to it’s superior reverse thrust and optimum pitch setting … resulting in no ‘prop walk’. The pitch setting is determined by two factors … Shaft RPM & Torque and the hydrodynamic force flowing over the blades (i.e. boat speed). RPM decreases pitch. Water flow increases pitch. The propeller will optimize the pitch setting to these two forces. Anytime you change one of the “forces” you will change the pitch setting until the “new pitch” is established based on the two new Input forces. For example, if you were going down the bay at 2200 RPM and 5.0 kts and you then increased RPM initially the pitch setting will be reduced. However boat speed / water speed will increase and so then the pitch will Increase to match the two new forces of say 2800 RPM and 7.5 kts
Autoprop is the cruising yachtsman’s propeller ‘par excellence’. Autoprops blades can rotate through 180 degrees and the subtlety of their design allows them to produce the same amount of thrust whether the yacht is in ahead or astern. It is a unique propeller which, unlike its competitors, excels in all aspects of a cruising yachts use and does not compromise any of them.
Autoprop’s unique design and superb build quality make it the first choice feathering propeller among cruising yachtsmen the world over, with drag reduction when sailing by at least 85%, and a unique ability to change pitch automatically to suit prevailing wind and sea conditions when motoring or motor sailing.
Sailing. The feathered image on the right shows how, when sailing, Autoprop reduces drag by up to 85% compared with a three blade fixed propeller; with the two blade propeller the reduction can be even greater. This drag reduction can equate to as much as one additional knot in sailing speed.
Motor Sailing. Autoprop automatically varies its pitch depending on the conditions. Put simply, as the wind or sea conditions vary so does the blade pitch of your Autoprop. The less pressure the Autoprop feels on its blades the more pitch is applied and vice versa. The result is maximum efficiency whatever the conditions, with increased speeds at lower engine revs and lower fuel consumption and emissions.
Motoring. With other feathering and fixed pitch propellers performance under engine is a compromise. No such compromise exists with Autoprop, her blades admittedly rather an odd shape, are the result of a huge investment in design time and testing. The Autoprop blades, unlike those of conventional propellers, maximise the thrust delivered whatever rpm the yachts engine is running at. Conventional propellers are designed to provide maximum thrust at the engines maximum output; at any other point up to maximum revs the propeller will be operating at less than its potential. Autoprop however, subtly varies its pitch to optimise thrust whatever the engine’s revolutions.
Manoeuvrability. In reverse the Autoprop blades swing through 180 degrees and present exactly the same blade shape as they do ahead. The result, the same excellent thrust, with greater stopping power and less prop walk.
Adverse weather conditions. Likewise in adverse weather conditions, the vessel’s speed will be reduced because of the adverse weather such as high winds and choppy sea conditions. The Autoprop senses the load acting upon it and reduces the pitch angle allowing the engine to to run to a higher maximum rpm. Much like travelling up a hill in your car, you need a lower gear ratio to allow the engine to run faster and produce more power.
Towing.This unique feature of the Autoprop, enables the full power of the engine to be used in situations such as towing, or in emergencies. With conventional propellers because the pitch is too coarse at very low speeds, the engine cannot achieve its full revolutions and therefore full thrust is not achievable.