Feathering MaxProp with Yanmar

[OrangeCrush]

I'm considering replacing my 3 blade fixed prop with a MaxProp this year. (Shannon 38, Yanmar 4JH5E, Transmission KM35P, gear ratio 2.6). I've got a quick question...



Since the prop doesn't always feather itself in light airs, I've read that MaxProp recommends putting it in reverse then back to neutral while the boat is still moving quickly. Then again, my Yanmar manual explicitly forbids sailing with the motor in reverse. I'm guessing that it wouldn't be much different than using reverse to slow down while coming to the dock, for example, but I wanted to see if anyone had the same concern. Thanks!

[sailorboy1]

Its standard to pop the trans into reverse once engine is off. Yanmar only says not to because it loads the cone over the long term.

[Eleuthera 2014]

Ask Maxprop what they suggest... I do as you state for my Volvo and it works well. GL

[Nineteen]

Hi
We have gad the Hydralign feathering prop on our Yanmar 3JH/Kanzaki for the last 19yrs. We pop it into reverse to fully weather the prop if it hasnt done it itself for a couple of seconds(usually when it is freshly greased as some of the grease pressure has to bleed off). We then put it back to neutral.

If you forget to put it back to neutral the cone will lock up tight enough over time that you can't pull it out of gear. This is not a big deal. You will just start the engine and as soon as it is idleing you can pop it out of reverse the same as always. It will not damage the cone clutch.

Hope this helps.

Cheers
Tom

[Bill O]

Originally Posted by OrangeCrush

I've read that MaxProp recommends putting it in reverse then back to neutral while the boat is still moving quickly.

+1 on this advice. Would say 50% of the time we need to pop it into reverse to get it to feather after we turn the motor off, then almost immediately can shift into neutral.


Bill O.

[OrangeCrush]

Originally Posted by Nineteen

If you forget to put it back to neutral the cone will lock up tight enough over time that you can't pull it out of gear.

Tom and Bill,

Yes thanks this is very helpful indeed. Ive made this mistake and wondered why it goes back into neutral if you do it quickly but not if you wait too long.

I think I’m moving forward on the max prop order. Having spoke with them at length, seems like there’s no real reason not to go with a 4 blade over the 3 blade except a small price difference. Let me know if anyone has a differing opinion. Thanks again for the help, all

[geoleo]

Originally Posted by OrangeCrush

Tom and Bill,

Yes thanks this is very helpful indeed. Ive made this mistake and wondered why it goes back into neutral if you do it quickly but not if you wait too long.

I think I’m moving forward on the max prop order. Having spoke with them at length, seems like there’s no real reason not to go with a 4 blade over the 3 blade except a small price difference. Let me know if anyone has a differing opinion. Thanks again for the help, all

3 blade is more efficient and less drag and cheaper.

[Bill O]

Originally Posted by OrangeCrush

Having spoke with them at length, seems like there’s no real reason not to go with a 4 blade over the 3 blade except a small price difference. Let me know if anyone has a differing opinion. Thanks again for the help, all

We looked at a 4 blade Autoprop and there was a discussion about the possibility of blade flex (thinner blades) on our 83mm hub. Don't know if this would be the same on the MaxProp and for your hub size.

On the plus side you'll get more torque w/a 4 blade and this is good if you need to punch through a decent sea state. The 3 blade does a good job so far, but for an experienced discussion would be nice to run both on the same boat to see if there really was any difference.
Would go w/a 4 blade if not much price difference.

MaxProp (and probably others) do sell refurbished props that carry the same warranty as a new, but for much less cost upfront. Usually have to inquire if they have any.


Bill O.

[OrangeCrush]

Great tip about asking for a refurbished one, I definitely will.

The primary reason I'm getting a feathering prop at all is to address this weird flutter I get when sailing fast and letting the 3 blade fixed prop spin in neutral (yanmar transmission). It's not the alignment since that has been checked and rechecked and it doesn't happen under motor power. I've determined that it comes from the 3 blade prop sticking out from behind the keel's deadwood unevenly on one side compared to the other, when one blade is on port and two are on starboard, for example. (You can see my previous posts on this if you wish)

Presumably the feathering prop will improve this problem no matter how many blades it has because it won't spin in neutral, but the possibility of port/starboard imbalance seems to me another good reason to favor the 4 blade design. Plus, at 23,000 pounds actual displacement, my boat is pretty heavy and it seems that more blades is an advantage for torque on heavier boats. Motoring into chop can be frustratingly slow with my current setup.

The second reason: right now my boat is a bit under-propped. I can rev it up to 3,250 rpms with full throttle when it should only go to 3,000 as per the manual. According to PYI Marine (Maxprop's USA dealer) it would be best to get the same size propeller (16") as I have now and adjust the RPMs with pitch only. If I went any bigger, they said, I might not have enough clearance for good water flow in the aperture. They don't know the size of the aperture yet or anything, but just that it's better not to mess with it if they can use pitch to address the relatively small adjustment needed.

So with the new properly adjusted 4 blade MaxProp I'm really hoping to achieve:
1) better torque into chop and more power at low rpms
2) elimination of the weird flutter/virbration when sailing fast in neutral

To a lesser extend I'm also looking forward to
3) Reduced drag and better speeds in light airs
4) Better reversing ability

Hopefully I'm on the right track because it is not cheap! Thanks again

[donradcliffe]

Don't just pop the transmission into reverse. Shut down the engine, put the transmission into reverse, and leave it there.

I've been doing this for decades on dozens of boats, most of them Yanmar powered, and it has never been a problem. Fixed, feathering, and folding props, its less wear and tear on the entire drive system.

[hlev00]

I have a Maxprop 3 blade and Yanmar 4JH4E on my Beneteau 423. To feather I have always 1) start sailing, 2) Engine in neutral, 3) stop engine, 4) transmission in reverse, 5) transmission back to neutral.

Over the years getting back into neutral takes longer an longer. I have had the prop serviced twice, most recently over this past winter. This season, getting back into neutral has become very difficult. Now we move the shifter as far as possible towards neutral and leave it. Almost always it eventually can be moved the last bit into neutral. When it doesn't, we give the ignition a very short crank while holding the shutdown button and it move easily into neutral.

Yesterday I was trying to diagnose the problem further. I disconnected the shifter from the transmission and operated the transmission directly. The same symptom appeared. What I noticed was that when I could not get the transmission out of reverse, I just needed to twist the shaft slightly in the reverse direction, then the transmission went easily into reverse. After this point, engine still off, the transmission moves easily between F-N-R.
I am worried that having used the above sequence for at least since we have owned the boat (nine years) I am damaging the transmission.

The other possibility that would seem just as likely is that despite having the prop serviced that it is still not feathering completely and so not allowing the transmission to slip out of gear do to slight pressure applied through the shaft. However, during the above test, after rotating the shaft slightly to allow the transmission to go to neutral, there is no spinning and no apparent pressure in that direction. That is, while in neutral, it seems to take the same force to turn the shaft in either direction by hand.

I will say that I do like the performance of the MaxProp otherwise.

Thanks,
Harry

[hlev00]

Fred at PYI just shared the attached Yanmar Bulletin from 2011. In it is the following statement

Feathering propeller:
When sailing under sail with engine stopped put control lever into reverse position, this enables the feathering propeller into feathering position and output-shaft stops from rotating. After this operation put the control lever back into neutral or remain reverse position as you like.


Notice:
Do above mentioned operations with a boat speed <3knts when sailing under sail with engine operation stopped.

I afraid that likely what we have doing wrong is using this technique when we have too much speed causing the transmission to "slam" into gear. Maybe we will have the cone drive looked at over the winter.


Harry

[NYSail]

And change the trans fluid every year.