Max-Prop automatic feathering propellers


Max-Prop is the leading low drag propeller on the market today. Since starting production in the 1970's Max-Prop has proven itself on racing and cruising boats around the world. With over 40,000 propellers in the water, the Max-Prop is tested daily in the harshest conditions and has established itself as the most efficient and reliable low drag propeller.

The combination of low drag, outstanding reverse power, efficient forward performance, and fail safe design makes Max-Prop the ideal sailboat propeller on the market today. Now with the introduction of the Whisper, Max-Prop has taken a large step forward in the propulsion of sailboats.


Many models of Max-Prop automatic feathering propellers available so you'll be sure to find the one that fits your needs perfectly.

Max-Prop Classic automatic feathering propeller


2 & 3 Blades
Available from 11" to 48"
For 3/4" to 3-1/2" shafts

Max-Prop Easy automatic feathing propeller


3 & 4 Blades
Available from 12" to 31"
For 1" to 2" shafts

Max-Prop Whisper automatic feathering propeller


5 Blade
Available from 18" to 50"
For 1" to 4" shafts

Max-Prop SailDrive automatic feathering propeller


2, 3 & 4 Blades

Features of a Max-Prop


One of the most important features of the Max-Prop is that it feathers automatically with the forward momentum of the boat. Once feathered, it provides the least possible drag (similar to a folding prop) improving the vessel's sailing speed by an average of 15% above a conventional fixed blade propeller.


In forward: the Max-Prop will offer 96% of the efficiency of a fixed blade propeller of the same diameter and pitch. The 4% loss in power can usually be eliminated by precisely matching the pitch of the Max-Prop to fit the boat engine combination. In reverse: the Max-Prop provides 80% more power than a comparable fixed blade propeller. The Max-Prop utilizes the same leading edge in forward as it does in reverse giving the propeller the same efficiency in both directions, whereas on a fixed blade propeller in reverse the trailing edge becomes the leading edge therefore reducing its power.


The Max-Prop uses a "differential" type design so that the blades cannot fail to open in forward or reverse. This positive system eliminates the problem associated with a folding propeller and its use of centrifugal force to open the blades. In a recent survey of Seven Sea Cruising Association readers the Max-Prop received a perfect rating on no failures ( one of only two products to receive such high praise). About 32,000 Max-Prop are in operation today!


The pitch setting on all Max-Prop models can be adjusted. Changing the pitch is very simple; it is done by changing the setting of the gear inside the propeller with the Classic (usually upon a haul out). Or by removing a bolt and replacing with one of a different length with the Easy and Whisper. The ability to adjust the pitch will help achieve the maximum efficiency from the engine without having to purchase a new propeller.


The Max-Prop will fit directly onto your existing shaft when the boat is hauled for installation. The Max-Prop will be matched to your specific shaft taper or SailDrive Spline. The only required maintenance is to grease the propeller once a year, and to replace anodes when they erode away.


Worldwide, many of the top racing boats have opted for the Max-Prop solution.


The two or the three blade Max-Prop is the propeller of choice for the cruising sailor. The combination of low drag, increased speed under sail, outstanding backing power, safety and maneuvering, and fail safe design makes the Max-Prop the ideal cruising propeller.

Advantages of a Max-Prop

Max-Prop advantage under sail

Under Sail...

A Max-Prop feathers to a low drag shape. Compared to a folding propeller, the extra wetted surface of the Max-Prop blades is offset by the reduction of projected area: A.

Max-Prop advantage in forward

In Forward...

The torque of the prop shaft acting on the "differential" type design will open the blades in unison to the preset pitch at any throttle setting. This will provide maximum efficiency (96% of same size fixed prop) plus eliminates the vibration problems of a folding prop.

Max-Prop advantage in reverse

In Reverse...

As in forward, the torque of the shaft will rotate the blades, 180 degrees in less than 3/4 of a shaft rotation, presenting the same leading edge and pitch in reverse. This provides better directional control and 80% greater power than a comparable fixed blade propeller.

Disadvantage of Folding Props

A folding propeller disadvantage under sail

Under Sail...

A folding propeller has low drag. The drag is directly proportional to the projected area: A.

A folding propeller disadvantage in forward

In Forward...

The blades will "slam" open and, if not perfectly aligned or true to each other, will cause vibration.

A folding propeller disadvantage in reverse

In Reverse...

In that the blades will not open to the maximum diameter (and occasionally not at all), the reverse power is very poor (much less than a fixed blade prop).

Disadvantage of Fixed Blade Props

A fixed blade propeller disadvantage under sail

Under Sail...

A fixed blade propeller includes a tremendous amount of drag, reducing the boats speed an average of 15%.

A fixed blade propeller disadvantage in forward

In Forward...

Fixed blade propellers provide maximum efficiency as long as the pitch is correct.

A fixed blade propeller disadvantage in reverse

In Reverse...

A fixed blade propeller works with the trailing edge as a leading edge, reducing its efficiency by 50%.


Here are common questions we receive about our Max-Props.
If you can't find an answer to your question here please feel free to contact us.

In simple terms greasing the Max-Prop once a year is perfect in most circumstances. The Max-Prop can be greased with the vessel on the hard or by a diver with the boat in the water. The more often you grease it the longer it will last, at a bare minimum it should be regreased every two years.

Anodes (Zinc or Aluminum) last anywhere between two weeks to two years depending on the galvanic activity on your boat and the water around your boat. On a new installation check the Anodes often until you determine how quickly are deteriorating in your slip or mooring. I would replace the Anode with every haul-out whether it is needed or not, it is inexpensive protection for an expensive piece of equipment.

With regards to antifouling on the Max-Prop, there are many stories of how various household products work to keep growth off the propeller. To be honest most of them work well if you don’t use the propeller, as they create a barrier that marine growth can’t adhere to. But, the more you use the propeller the faster these and most any product will wash/wear off. The tips speeds generated by a propeller will wear the paint or coating at the tips of the blade. There is a very good product called Velox Plus, it works very well on the propeller. It costs about $150.00 for an application. While no product is perfect, it should last a season when applied correctly, but the life ultimately depend on the use the propeller gets.

The Max-Prop can be set for either right or left rotation, it does not matter to the propeller. The rotation of the shaft is determined when viewed from the stern of the vessel looking forward. A shaft that rotates clockwise will have a right rotation propeller and a shaft that rotates Counter-clockwise will have a left hand propeller.

For a 2 blade measure from the tip of one blade to the tip of the other, this is the diameter. For a 3, 4 or 5 blade, measure the radius, from the center of the propeller to the tip of one blade and double that number for the diameter.

In a perfect world, while powering in flat water with a clean hull and propeller, the propeller will allow the engine to attain its maximum rated Rpm. If the propeller allows the engine to attain over its maximum rater Rpm then it is not creating enough load to the engine and you are not getting efficient thrust for the fuel that is being used. Conversely if the propeller does not allow the engine to attain its maximum Rpm then it is overloading it and could be shortening the life of the engine. If you attain too many Rpm then you will need to increase the blade angle of the propeller at your next haul-out. If you attain too few Rpm then you will need to decrease the blade angle of the propeller.

The grease we recommend is Lubriplate 130AA. As it has been extensively tested and it performs well in all water temperatures. As an expensive alternative Lewmar winch grease performs well especially in warmer waters.

To increase the maximum RPM’s that the engine can attain when powering in flat water you will need to decrease the blade angle setting. Each two degree change in blade angle will increase the maximum attainable RPM’s by about 13%.

To a certain extent more zinc is better. The Max-Prop three blade has a zinc on it as it is often installed within an aperture where there is no room for a shaft zinc, and the propeller requires some protection. If the propeller shaft is supported by a strut it is a good idea to add an additional zinc.

Yes, the Max-Prop can be reconditioned and repaired. Whether that is normal wear, a blade bent in half, or pitting from corrosion, most damage can be repaired. To repair the propeller we will need the entire propeller, including the hub from the shaft sent to PYI Inc.