the Super Maramu was first delivered with the Max-Prop as a standard, and a spare fixed prop (LH 21"x16"), until n° 100 when AMEL decided to fit the AUTOPROP as the standard (and still a fixed prop as a spare).
The Max-Prop has always been fitted with a zinc (because no plastic nose was available like on the AUTOPROP...) but as you know, the zinc deteriorates (especially around the fastening stainless steel screws) and because of vibrations and rotation, quickly leaves. In order the prop (whatever it is) is then still protected from galvanic corrosion, AMEL connects the C-drive (and therefore, the shaft and propeller) to the rudder zincs, which are less prone to leave because of speed and vibrations.
So, there is no really need for a zinc on the propeller (whatever it is) as long as you have a good connection with the rudder zincs. You all noticed that it is not possible to install a zinc on the spare fixed prop you have on board.
At every haul-out, you should check the electric relation from propeller to rudder zincs (resistance should be 0 Ohm).
The Max-Prop is very good when sailing (very little drag) but not so good in docking manoeuvers (especially when shifting from forward to reverse). It also prevents the engine to get full power when the boat is stopped (or at very low speed).
The AUTOPROP allows you to get full power (3500 rpm) as soon as you push the throttle to full gas (and when the boat has no speed). It is not too bad when sailing, and allows using a prop-shaft alternator (for those who have one).
Both propellers need to be very clean to give full thrust.
Both propellers need a thorough greasing at each haul-out.
Enjoy sailing (without too much motoring...)
It's a long story, but I couldn't get my old Volvo TMD past 2200rpm, spent thousands of dollars on several mechanics, then finally got the AutoProp serial number and was told by Bruntons that it was what they recommended for the 100 HP Yanmar. My spare fixed prop was also over propped according to a prop shop in Norfolk VA. I had it cut down and repitched to their calculations and voila! 2900rpm.
The AutoProp could not be repitched. Everyone has said the AutoProp is very sensitive to any growth and has to be serviced regularly to work correctly. I got a good deal on the MaxProp and have been very happy with it. When I repowered with the 110HP Yanmar, I was able to repitch the MaxProp by changing the settings and it works fine with the new engine.
I still have the old AutoProp if anyone is interested in buying it.
Thank you Kent
for the good idea i will try and let's see what happens.
Why did you switch the Autoprp against the Maxprop?
SM Baloo # 222