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Go Back   SailNet Community > On Board > Gear & Maintenance
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  #11  
Old 07-16-2006
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Props

Not true with a MAX Prop. The engine must be in forward gear and there must be water flow across the prop for it to feather.
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Props

Only 45 years in boating. Yourt suggestion to avoid feathering props because some apparent drunk didn't know how to use it appears ludicrous. Beside, in order for a Max Prop to feather, the boat must be moving and the engine shut off in gear.
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Old 07-16-2006
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OK, as a new feathering prop owner (a Kiwi came with our Freedom 35) these letters are rather sobering. What I need to know just how I work the prop to make sure it does not fail on me in a sticky situation. We had a traditional 2 blade fixed on our Pearson 36 and this feathering stuff is all new to me, the helmsperson.

Thanks, Faith
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Old 07-16-2006
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As the owner of a Freedom 35 with a Kiwi feathering prop this thread is of concern. We've had a traditional 2 blade before and the feathering business, while nice and responsive, is new to me. Just how am I supposed to leave it after I turn it off? And...the other day we were charged ahead at about 6 K and turned on the enginen to help us come about in a stiff wind. The prop did not work. We thought it had fallen off? But thenk, at a lower speed it did. What's up? Thanks, Faith
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Old 07-17-2006
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I have a Cabo Rico 38 with a Perkins 50 HP diesel engine. The original 2 bladed propeller did not have enough reverse to back up the boat to my satisifaction. I purchased a "Paul E. Luke" feathering propeller (16x11" three blade) and the difference is very significant. With the 2 blade prop, I cruised at about 6 knots at 2600 rpm. With the Luke prop, I get the same speed at 2200 rpm. What really changed is the reverse. It was like turbo charging the engine. The boat would stop much faster and there is very little prop walk. The three blades really grabs the water. Altho the feathering prop is quite expensive, I beleive that it is worth the money.

John

SV "Papillon" CR 38 #24
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Old 07-17-2006
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I have fixed 2 bladed on my twin Yanmars. They freewheel when sailing (yes, it's OK) and according to the performance charts offer minimum drag under sail. Under power, they are adequate.

My understanding is that as long as the engine's transmission has it's independent oil reservoir, freewheeling the prop under sail is OK. The prop performance charts I've seen (MIT study) concerning the drag of a freewheeling, 2 bladed prop under sail, show that it's a non performance issue.

As for the feathering props... they'd be great when there's the possiblity of snagging a crab trap, or if your drive train prohibits freewheeling. If you are able to freewheel the prop, in my opinion there's not much of a cost / benefit ratio.

Here's the MIT study. It's worth a look before you spend the money.

http://thepracticalsailor.com/Files/.../propeller.pdf

Rick in Florida
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Old 07-17-2006
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I have considered buying a feathering prop so this threadis very interesting to me From what I,ve read most boats will gain about .3 to .5 knots. If you could sail around the world at the equater an increase in speed of .3 knots would save you 5.75 days. you would travel an extra 7.2 miles per day. or 12.79 hours less on a 2000 mile crossing. If I piked up an extra knot I think I would sighn up tomorrow. But . 3 for me just doesnt justifie th cost. They say the average cruiser only spends ten percent of their time underway I could have a lot of fun on 2500 dollars!
Rick That link must only work if you give PS money. I've seen it before but would like to see it again. As for free wheeling the individual manufacturers are pretty specific on weather or not you can freewheel . most transmissions dont drive thier own oil pump, Thats done buy your engine. so if your engine is off no oil is supplied to the gears and bearings some trans. have a slinger that acomplishes this but I would deffinately check to see what is recomended for your particular gear I have a yanmar package and it is not to be free wheeled.
one of the reasons I would want a feathering prop would be to reduce the strain on The trans.
Any one that has a Max prop will the shaft stop when the prop is featherd or does it continue to spin slowly?
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So, lets take a closer look at the mechanics of the maxprop, as there seem to be some experts here, let's see how bright they really are. Nothing worse than know-it-alls who don't know what they are talking about. Well, that's not true, but they can be annoying.

Boat is tied to the dock, engine being shifted from forward to reverse, at idle. Design of the maxprop says it will always offer the proper leading edge of the blades to the water, whether in forward or reverse. If anyone has any doubt, you need only visit the website, as that fact is clearly illustrated on the first page. They are great props, by the way.

Now, it seems to me, that if the prop rotates the blades 180 degrees, it has to go through FEATHER to get from one stop to the other. Get it? No motion of the boat necessary. No waterflow over the blades needed. Bang, bang, bang. Through feather. Study it until you got it, because unless you understand that, then you could NEVER understand how someone could pass through neutral, as I said, then pop it back to neutral in a flash, which many, many people do in the normal course of docking a boat, and since we're at idle, and the rotation of the maxprop at idle is often sluggish, on any given day at any time it is possible to leave the prop feathered, or nearly so, and it happens far more than you might think.

Then there's the other thing down here in Florida, and especially on the southern gulf coast. Boats tied to docks near the mouth of extended canals experience considerable current at peak ebb and flow tide periods. How much current speed does it take to feather a maxprop? Will four knots do it? There are plenty of four knot canals. We get it every day here in Bradenton.

Now, I don't give a damn about anybody's lifetime on a dock. Just because someone owns a piano, don't make him Beethoven. I've done dozens of these props and run my own yacht service for years and met a lot of long talkers who didn't understand the machinery they were explaining to the others on the dock.

And as far as the drinking, I said drinking, not drunk. You don't have to be drunk to slip a shifter through neutral, but it is my observed experience (I don't drink) that a good many boaters are tired and a tad 'under the weather' when coming back to the dock on weekend evenings, and the shifter work is often less than optimal. Anyone who denies that hasn't been in a marina enough.

If you got your feelings hurt or got all defensive about what you perceive as my arrogance, that's too bad. You ought to know better at your age than to crack wise at a man when he's relating a true yacht maintainance story. That's just bad manners and old sailors like me are just apt to spit back. If you don't get it, you don't get it. Don't be talking crap like the other guys a liar and this couldn't happen when it does all the time.

Last edited by Hawkeye25; 07-17-2006 at 10:56 PM.
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Old 07-18-2006
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Hmmm....don't know how that happend.

This will work:

http://thepracticalsailor.com/Files/.../propeller.pdf
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Old 07-18-2006
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Feathering props

Hmmm-- Eight years and 1500 hours on a two blade Max Prop and three years and 500 hours on a three blade with flawless performance. The engine must be shut off in gear for the prop to feather. Hence, four knots of current with the engine in neutral will only cause the shaft to spin (as a fixed prop).
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