Max Prop 3 Blade 12" prop

[pcupach]

I installed a Max Prop 3 Blade 12inch prop this winter.
I have a Ranger 33 with an Atomic 4 1:1 direct drive transmission.
I removed a folding 2-blade Martec prop.
-I was experiencing a gross amount of prop walk with the Martec 2 blad folding prop.
--The expectation is: The 3 blade Max Prop will reduce the prop walk I have been experiencing with the Martec 2 blade folding prop.

The removal of the Martec prop was simple, I soaked it down with PB Blaster a few days prior to trying to remove it.
The Maxprop install was straight forward. The guys at PYI Maxprop provided the pitch ratio for the A4 and the settings I needed.
Be sure to order the grease gun and grease from them when you order the prop...that will save you time delay.
Ill post the pitch setting and performance info later this summer.
Im still waiting to get back in the water...

[sastanley]

Wow...I am very interested to hear these details. A 3-blade direct drive prop at 12" diameter must be very light on the pitch. Even most 2-blade Martec's for A-4's I've researched should be 12 x 5 or maybe 12 x 6.

I am too cheap to lay out the $$$ for a Max prop but they are very cool. I wonder why they did not think 2 blades were sufficient. Isn't the whole point of a Max prop is that the blades rotate around on the hub to give almost the same thrust in reverse without the walk??

[Boat]

Very interested as well. That is the exact one I want to install on my Newport 30. I currently have a three blade fixed 11x6

[pcupach]

The 12" 3-blade MAXPROP is working even better than expected.

SAILING: While sailing I haven't seen noticeable speed reduction compared to the 2-blade folding MARATEK prop.

-IN FWD: My Ranger 33 now gets up to 6.3knts inside of 4 boat length with no head wind or waves. 3/4 throttle engine ran quiet and running smooth
In Fwd with With a 20knt head wind and choppy water conditions (spray over the bow). I maintained 5.7kts at 3/4 throttle. Engine seemed like it was running quieter and smoother.

Transition to REV from FWD from 6knts (no head wind and flat water).
--1/2 throttle boat came to a complete stop inside of a couple of boat lengths.

Transition from FWD to REV at 2-3knts: Boat stopped inside of 1 boat length

When docking in FWD motion. 1 knot or less movement gear in neutral position: Transition to REV was seamless and stopped the boat on the spot I wanted it to

In REV from dock: (5-7knt cross wind) Boat went straight back no prop walk.
When the wind was 10mph bow will swing with the wind, but a little bit of increase in throttle and rudder input straitened it out enough to clear the port and starboard 35ft dock fingers without the boat touching the dock.
(slip is 35ftlong x 14ftWide) Ranger 33 has a 9.5ft beam

Executing a standing turn: Boat basically spun on it axis. It took less rpms and less time to execute the turn than the old 2 blade MARATEk folding prop.

Overall this prop was $$, but the response is night and day different than the 2 blade folding 9" MARATEK prop.
Hindsight: I've spoken with people that have the 2 blade Max Prop and they see similar result as I have.

[blairm87]

I have a 2:1 reduction on my A4, with a 2 blade prop for a 36ft Columbia. I'm also interested in a 3 blade prop to help with navigating a tight marina. Any suggest for 3 blade props since I have a reduction gear and not direct drive?

[ndutton]

Originally Posted by blairm87

I have a 2:1 reduction on my A4 . . . . . . I'm also interested in a 3 blade prop to help with navigating a tight marina. Any suggest for 3 blade props since I have a reduction gear and not direct drive?

Per Atomic 4 Specifications by Robert Hess:
3 Blade (recommended for areas with severe currents, winds, tides)
2:1 Reduction Drive: 12 x 9, 12 x 10, 13 x 8, 13 x 9

[Al Schober]

I'm going to muddy the waters here a bit.
IMHO, prop walk is caused by the prop being close to the hull. As the prop swings, it takes water with it and the water close to the hull pushes against the hull - the water away from the hull pushes on the ocean. This is usually a problem in reverse as the prop wash aft is NOT pushing against the rudder and causes an uncorrectable course deviation. It does not cause a problem going forward as the prop wash goes against the rudder and is correctable.
Folks have suggested that going from 2 blade to 3 blade propellers helps, but I suspect that this is only the case if the 3 blade prop is smaller and has more hull clearance - giving less push against the hull.
I formerly had a Tartan 30 with a 2 blade propeller. Propeller was very close (1/2") to the hull, but was right behind the keel. The close clearance would tend to cause prop walk, but the close proximity to the keel tended to minimize it (small lever for the force to act on). I had to back into my former slip, so learned to deal with the prop walk: First, get the boat moving slowly in reverse, then shift to neutral. With the boat moving backward, the rudder would work, and I could control direction. If speed became too slow, I'd give it another shot in reverse. Key is to limit your speed to that at which you don't mind hitting something (can I fend off?).