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Old 10-03-2018, 09:14   #16
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Re: Proper shutdown/start sequence with a Maxprop?

Interesting thread, but a bit surprising to me.
The authorized MaxPro installer who installed the MaxPro on my boat told me that I do not need to do anything for the blades to feather when turning the engine OFF, in neutral as well.
He even came out on the boat with me to show the MaxPro operation and the MaxPro did work as he stated. Since then, I followed that instruction, kept turning the engine off in neutral and did nothing else, and never had the feeling that the MaxPro was not feathering.
I now see that there are instructions that came with the MaxPro (as usual, I did not even looked at them after being out with the mechanic), and indeed they contradict what he said.
But why does the MaxPro seem to follow what the mechanic told me?
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Old 10-03-2018, 09:27   #17
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Re: Proper shutdown/start sequence with a Maxprop?

I have one more source of confusion from the instructions...
Where it says "2 or 3 knots in forward" does it mean that they want to make sure the boat has some forward motion (otherwise, the MaxPro would not feather, of course), or it means that the boat should not be going forward very fast? We always turn the engine off only if we are sailing at three knots or more.
Could this be the reason why our MaxPro seems to feather quite happily when in neutral? It only needs forward motion?
The relevant question is also, what if you are sailing at say, 10 knots, when you turn the engine off? (it happens sometimes, we raise the main and we first go on a tack before turning off the engine, just to make sure we are in control before stopping the engine...)
Is going faster than 2 or 3 knots not recommended when feathering?
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Old 10-03-2018, 11:09   #18
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Re: Proper shutdown/start sequence with a Maxprop?

Shifting into neutral, at speed, is not much of a problem. Shifting into reverse, to feather the prop, at speed, can be done, but it is much tougher on the transmission and on all the moving parts of the Max Prop.

Rather than depending upon a "feeling" that the prop is feathered, you can actually listen for the hum of the prop shaft, or, if convenient, you can actually look at it. I would say, in many years of using max props, that they feathered about two thirds of the time, without going into reverse, but that means they didn't feather one third of the time, which is a lot.

To add to the confusion, over the years, Max Prop has changed their recommendations, sometimes completely reversing them. So, don't feel bad!

Cheers,
Tim
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Old 11-03-2018, 06:18   #19
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Re: Proper shutdown/start sequence with a Maxprop?

I suspect some people who are putting the engine in reverse are not actually feathering their props every time, but putting them unfeathered into the reverse position to lock up the shaft, to make it look feathered. To test this, put the gearbox into neutral after the engine has stopped or after the shaft is locked up in reverse. If the shaft turns any more than a wobble or a very, very slow turn then it is not feathered. You will be able to grab the shaft and stop it moving with your hand if it is feathered. Another clue as to this happening is not being able to move the gearbox out of reverse. The pressure from the unfeathered prop trying to turn the gearbox will lock up the gears.

Observe the process of feathering when the boat is on the hard. You can then understand the process. The prop will feather when the water pressure is highest on the front side of the trailing edge of the blade. It will only do that when the prop is turning just a bit slower than the waterflow and a tiny bit faster than the prop is being driven. It will only do that if the prop is stopped slowly by shutting down the engine from a point where it is turning just a bit faster than the waterflow and pushing the boat. It needs a quarter turn to do that so it can only happen when the prop stops slowly after pressing the kill button.

By the way a properly greased prop improves things a lot and shutting down in the way I described earlier I get a 95% hit rate. Something is going wrong for Contrail.
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Old 11-03-2018, 06:57   #20
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Re: Proper shutdown/start sequence with a Maxprop?

I have chatted with PYI (maxprop distributor) about the right technique for feathering. Stop engine in forward, speed isn't that important (typically I'm going 7 knots under sail with the engine in slow forward). Then shift to reverse. For Volvo saildrives they recommend leaving in reverse because that is what the Volvo manual says.
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Old 11-03-2018, 08:39   #21
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Re: Proper shutdown/start sequence with a Maxprop?

I installed the 3 bladed max prop on the boat when new back in 1985 and it has been great ever since. Several years ago put the zirk fittings on so no longer have to take it apart to apply grease. My sequence has been power in forward to get sails raised and then shift to neutral sailing. Once I see that sails are doing well....simply turn the engine off and sail with the gear in neutral. A couple of years ago I started to mess with putting the gear in reverse when sailing, but looking at the max prop on the hard ...I don't see the purpose. On the hard with the blades in forward position see what it takes to feather them. You will apply pressure to the back of the blades simulating the flow of water as if you were sailing. Notice that the shaft needs to turn to achieve the feathered position. Once feathered it will stay feathered as long as you sail forward or are be calmed. I see no need for locking that shaft in reverse.
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Old 11-03-2018, 09:24   #22
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Re: Proper shutdown/start sequence with a Maxprop?

Quote:
Originally Posted by lancelot9898 View Post
Once feathered it will stay feathered as long as you sail forward or are be calmed. I see no need for locking that shaft in reverse.
I've found that when in neutral, my feathered Maxprop will start spinning when we get a strong shove by large quartering seas. I keep the transmission in reverse.
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Old 11-03-2018, 16:44   #23
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Re: Proper shutdown/start sequence with a Maxprop?

I don't have to remove mine to grease it. They make longer grease fittings that you use then replace them with the plugs.
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Old 01-06-2020, 09:19   #24
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Re: Proper shutdown/start sequence with a Maxprop?

I know this is an old thread but hoping to get a bit of your insight... I just installed a Variprop which has similar shutdown instructions as the maxprop: (Power forward at ~3 knots, shut off engine, then put in reverse. Then either leave in reverse or shift back into neutral as desired)

My question is in regards to the 5 minute cool-down period required by my Yanmar manual, which is intended to distribute heat evenly through the exhaust system. If I'm in very light airs and decide to sail, then I will have to idle in neutral for 5 minutes first, then power up in forward to get to 3-4 knots, then shut down. But powering up would presumably necessitate another cool down period.

I'm not sure many people adhere to this cool-down rule but I always have. I suppose I could feather the prop as directed then restart the engine in neutral to let it cool down but that seems a bit silly.

Has anyone thought about this?
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