Maxprop installation

[ANTIDOTO II]

Thank you very much!!!

[ANTIDOTO II]

Thank you

[ANTIDOTO II]

Thank you very much!

[argonauta1]

Good advice as to the location of settings as these are of most important to any owners as you realize. The manufacturer will have some valid settings which can be fine tuned based upon performance outcome in the water. Recommended settings should be close though. If they turn out to be too coarse you will find that your max engine rpm achievable will be too low. A caution: do not attempt to run at max rpm achievable if the rpm is lower than expected as you will run the risk of burning valves due to a high cylinder head temperature as you will be over boosting the engine. So throttle back by 300 rpm or so and take what you get in speed which will be relatively high for the rpm.

In my case, the folks who installed our max prop just slapped it on with no regard to settings and splashed the yacht. I ended up with a max rpm of about 1500 on a Yanmar 4 banger normally aspirated so we had to haul and reset using factory recommended setting. They turned out to be a bit coarse as we could not get over 2900 RPM but I lived with that as 2500 rpm gave us hull speed and we found 2000 rpm was fine for economical cruise.

Good luck, a Max Prop is a good piece of gear which took us on a circumnavigation and beyond.

[walkabout08]

FYI once you’re back in the water you’ll be looking to see if the boat can achieve max rpm’s per spec at full throttle. The correct pitch will allow this, too much pitch and your rpm’s will stay below the spec’s max, too little and your rpm’s will run higher than spec’d.

[ANTIDOTO II]

Thank you very much for your answer. I have already communicated with PYI. The guys there know very well the boat, the engine and the propeller. They gave me instructions to install the propeller back properly. Of course I will follow your advice about rpm.
Thank you very much once more!

[Craig Staunton]

Be aware the prop can be reassembled with the correct pitch but the wrong direction. I had an "expert" service mine and when I was launched, forward was reverse and vice versa. Not easy to putter around for half an hour while the yard launched another yacht before I was summoned to reverse 100 meters between moored boats back to the travel lift having to get my head around the forward reverse lever

[Colonel Bob]

Originally Posted by ANTIDOTO II

Hello to you all. I have just bought a HALBERG RASSY 352/1981 with a volvo penta MD21A.
I disassembled the 3 blade maxprop propeller without leaving marks. Gould anyone please give me instructions to install it properly? Thank you!

Contact Jerome Blakely at PYI ((425) 355-3669). He's a great guy and a big help. He can provide the specific settings for your boat.

[nuku34]

Re refitting old Classic props without set screws for grease nipples:
This not rocket science. You can buy a mild steel grease nipple from any auto supply (doesn't need to be stainless as it is removed from prop and replaced by a stainless set screw with hex socket drive before the boat goes in the water). The holes for the 2 stainless set screws, (one for the nipple and one for the air to get out), which have the same thread as the grease nipple, have to be drilled and tapped anyway, and their position can be determined from looking at pictures of recent Max props.

[PerfectPirate]

Some thoughts about fitting the grease nipples. First, the PYI kit is not that expensive and it comes with everything: nipples, set screws, drill bit, tap, allen key and clear instructions. Second, BOTH holes need to have grease injected, until you literally see grease escaping out around the front end of the prop and pivot points of the blades. I found it invaluable to have a proper grease gun which could snap onto the nipple. PYI also sells a package with a grease gun and the correct type of grease. I also found it problematic to get the tap started on the one hole because of the angle inherent in the shape of the prop body. The solution was to use a slightly larger drill bit to oversize just the opening of the hole, to a depth of maybe 1/32nd of an inch, which then gave the threads on the tap an even bite all the way around.

The original owner of my boat left clear directions in the MaxProp manual about which settings he had used for setting the pitch. He had chosen these settings based on Yanmar's recommendations for the engine and actually said that he had over-pitched the prop by one setting to compensate for a slightly smaller diameter. These settings had been used for 48 years. However, in the brief time that I had the boat in the water before hauling for refitting, I had found that my top speed was limited to 5 knots at about 2,000 RPM. Any attempt to push the RPM higher simply resulted in the prop thrashing and cavitating. After purchasing and studying a copy of the "Propeller Handbook", by Gerr, I decided to further increase the pitch by one setting , which is two degrees. The difference was like night and day. Now, at 2000 RPM she moves at just over 6 knots in flat water. Taking the engine up to full power RPM gets me up to hull speed, without any thrashing or cavitation. It boggles my mind that previous owners lived with such inadequate performance for decades simply because they were not willing to experiment a bit with the pitch.

[MicHughV]

To reset an earlier model Max Prop underwater requires 8 arms and a good set of teeth to hold odds and ends.
Doing all this in murky water is an extra skill.

Experts like fstbttm can probably do this with his eyes closed.

I installed a two blade Max Prop on the dry and it was challenging enough to make me think twice about doing it under water.

[SV Confianza]

I couldn’t fathom doing it underwater…

[fstbttms]

Originally Posted by MicHughV

To reset an earlier model Max Prop underwater requires 8 arms and a good set of teeth to hold odds and ends.
Doing all this in murky water is an extra skill.

Experts like fstbttm can probably do this with his eyes closed.

I installed a two blade Max Prop on the dry and it was challenging enough to make me think twice about doing it under water.

I won't even touch a 2-blade Classic. Much more difficult to install than the 3-blade version

[ANTIDOTO II]

Hello,
That was not the subject, but anyway thank you fir your response.

[fstbttms]

Originally Posted by ANTIDOTO II

Hello,
That was not the subject, but anyway thank you fir your response.

Guess what? Not every reply in this thread is is going to be 100% directly related to your initial post. Like any conversation, the subject may wander a bit, as this one has. In addition, you are not required to "direct the thread's traffic", as it were. What you should do however, is to quote the person to whom you are replying. That makes it easier for all your readers to know to whom you are replying. It's just basic forum ettiqutte.