Autoprop vs Maxprop

Re: Setting Autoprops and how They compare with Maxprop

Charles,

The Maxprop is more expensive than the Autoprop. For my boat it's £1750 for the Autoprop whereas the Maxprop is about £2k. The negatives that I've heard regarding the Autoprop are:

1) because the blades pitch independently there can be problems where blades are fouled unevenly causing vibration as the blades set at different pitches.

2) When sailing the blades hang down and cause drag

3) The blades are small in area and have to be heavy (because they rely on centrifugal force to deploy) and therefore are inefficient.

The plus for Autoprop over Maxprop seems to be excellent motor-sailing characteristics.

When I spoke to both firms at LIBS they were both respectful of each others products - which makes it even more difficult to choose!

rob
 
Re: Setting Autoprops and how They compare with Maxprop

Forgot that the vibration was a symptom of the blades not setting properly and that was also one of the reasons a neighbour was considering the change.

I certainly know that my Maxprop is a lot smoother than the fixed two blader I had.
 
You are not comparing like for like.

Ignoring Fixed Props and Folding props you then have Feathering props and Self Pitching Props.

The Autoprop is unique I believe in being the only self pitching prop, great for motorsailing but does have more drag than both feathering and folding props when sailing. As others have mentioned it adjusts its pitch automatically to deal effectively with the work it has to do.

The Maxiprop is a feathering prop. Other makes are the J prop, Variprop, and the Kiwiprop and Aquastream. I believe most come in 2/3 blades but the Variprop comes in 2/3 & 4 blade configerations

Of these
Aquastream is stainless steel and pitch can be adjusted externally no damper for changing direction. I like the idea of SS prop on SS shaft (& thinner blades) but it is expensive.
Kiwiprop - again pitch can be adjusted externally, no internal damper for changing direction and blades are made of plastic limiting the power they can handle to 56HP.
J prop I know little about.

Maxiprop -the pitch is adjusted when building the assembly on the shaft hence lift out for removal/adjustment and they don't have an internal damper. Have 2 sizes of hubs -larger for heavier use. Many have been sold so on a standard boat/engine configeration where the optimum pitch angles are well known I believe it will be fine.

Variprop has external pitch adjustment and is supplied as a complete assembly to slide onto the shaft. It also has internal circlips that act as a damping cam when changing direction. I had one on a previous charter boat with heavy usage and found it fine. For current boat I have just bought a 4 bladed one as power is 75HP and it should be much quieter, smoother and have zero vibration.

Props like boats are also a compromise. I love sailing and hate the thought of losing speed due to prop resistance and I tend to either sail or motor.

On all these props the anodes are dispproportionatly expensive so I would pre order 3 to 5 years worth with the prop and try to get a cheap deal for the lot.

Hope this helps.
 
Re: Setting Autoprops and how They compare with Maxprop

[ QUOTE ]
Charles,

<<The Maxprop is more expensive than the Autoprop. For my boat it's £1750 for the Autoprop whereas the Maxprop is about £2k.>>

When I did my research at the beginning and revisited it about six years ago the prices were the other way around

<<The negatives that I've heard regarding the Autoprop are:

1) because the blades pitch independently there can be problems where blades are fouled unevenly causing vibration as the blades set at different pitches.>>

Never happened to me and I think you'll find it's a rumour spread by disbelievers to confuse the incognoscenti.

2) When sailing the blades hang down and cause drag

<<Not true - just have a look at the Autoprop when under way>>

<<3) The blades are small in area and have to be heavy (because they rely on centrifugal force to deploy) and therefore are inefficient.>>

The area of the Autoprop blade is about 120% the Maxprop area - why not have a look and compare similar specifications. It's that additional area and the force required to feather the blades that give the Maxprop its lesser drag then the Autoprop.

The plus for Autoprop over Maxprop seems to be excellent motor-sailing characteristics.

When I spoke to both firms at LIBS they were both respectful of each others products - which makes it even more difficult to choose!

rob

[/ QUOTE ]
 
Re: Setting Autoprops and how They compare with Maxprop

I am interested too: is it the blades or the hub ?

because at only 40euro a blade (in the continent) the difference in price would allow for quite a number of spare parts -.<)
 
I have a three bladed autoprop and it does what is claimed. Lower revs, more speed etc. My wife is happy as it makes a better motor boat of our Dehler 36!! Had a Volvo 3 bladed folding prop and the Brunton is much better. Prop walk also gone. Also recovers quicker from being slowed by wash, eg the Cowes ferries! Have towed a Rival 38 at 2800 revs at just over 5kts. It is disconcerting at first to hear the engine revs reduce at a constant throttle setting as you accelerate and the blades 'bite'. No adjustment necessary of course.
 
You must log in or register to reply here.

Share this page

Top