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Old 02-08-2011, 00:39   #16
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Re: Any Opinions on Max Props for a 47' Sailboat ?

i went with the bow thruster i have a feathering prop on my nantucket islander 38 the thuster makes jogging in frount of the many briges on the ICW very easy
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Old 02-08-2011, 04:21   #17
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Re: Any Opinions on Max Props for a 47' Sailboat ?

Here are my thoughts on folding and feather props. Disclaimer. I've never had one nor direct experience with the of any substance.

Sailboats go slow. The go slower in light air and to maximize speed... efficiency the sailor adapts various strategies including sail trim, weight distribution, a "slippery" bottom. A folding or feather prop fall into the last category. They are reputed to reduce drag and therefore add a bit of speed to light air sailing.

In heavy conditions a foul bottom or a slippery form or weight distribution are less or sometimes not even the issue... when the boat is driven to hull speed.

The down side is performance when motoring... and maintenance. Folding and feathering props seem to reduce some motoring performance, such as backing or failing to open or perhaps requiring more fuel.. ie less efficient than fix blade props. There are a lot of variables so there no once size fits all answer about performance while motoring. My sense is that the trade off is acceptable to those who have them for better light wind sailing a reduced performance under power. And they are very expensive to boot.

Racers will be the ones to consider folding props. Less so for cruisers. It should be pointed out that many cruisers need to get to their destination on some sort of schedule... be it arrive before nightfall in an new harbor or get to an anchorage before all the good spots are taken! Accordingly cruisers will motor or motor sail to get there.

I personally have a 4 knot rule when I am going someplace.. as opposed to being out for a day sail to no where. When sailing speed over the bottom drops to 4 knots. the motor goes on. The boat as a big auxiliary engine which can drive it to hull speed in most conditions and we use it! Additionally, I like the prop to be very responsive in tight quarters... at quayside or in marinas entering or leaving slips... which we do very very very rarely. A responsive prop is part of maneuverability.

Since we are not into light wind sailing as we are cruisers there is little to no benefit to a folding or feathering prop... and several negatives. I suppose there are some speed advantages in the 4 knot to hull speed range, but I am unaware of the magnitude of these with a folding or feathering prop.

Frankly, I don't see the benefit of folding and feathering props on a long heavy yacht and one which is not sailed in light air and racing.

What do I know?
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Old 02-08-2011, 04:38   #18
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Re: Any Opinions on Max Props for a 47' Sailboat?

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Originally Posted by compdoc View Post
this my first post. My new [to me] Norseman 447 AC w/ Maxprop walks uncontrollably to stbd in reverse at any speed with or without gear in reverse or neutral. Doesn't matter if helm is neutral or to port. So bad that I'm considering a bow thruster. Any suggestions?
Suggest you pick a nice quiet day and find a buoy where there's little or no current or lay down a float of some sort. Then, practice backing with the new-to-you Norseman and MaxProp.

MaxProps tend to have much better power and control in reverse than do fixed props. Ask any owner.

You're probably not moving fast enough in reverse to be able to steer. The trick is to use the prop intermittently and with quite a bit of power to get the boat moving in reverse, then put it in neutral and use a lot of rudder to steer the boat. Also, you can use prop wash to kick the stern in the direction you want it to go. Rudder hard over one way or another, and give it a short burst of power in forward.

Try backing a long ways with some speed on, using the prop just to keep you moving and the rudder to steer in reverse.

Knowing your boat backs to starboard or port can be used to advantage when docking. For example, you can approach a T-head at an angle with your fenders out on the port side, turn right just before the dock, and as you ease the boat into reverse the prop will both slow you down and will keep the stern from banging into the dock.

It's all about timing and knowing your boat and knowing how to maneuver with what you've got. Practice, practice, practice.

Bill
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Old 02-08-2011, 04:43   #19
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Re: Any Opinions on Max Props for a 47' Sailboat ?

DefJef,

I completely disagree with most of that.

Having had a 3-blade MaxProp for 20+ years on my boat, and having delivered and maneuvered many boats of all sizes without feathering props, I have to say that I'd never have a boat without one.

After a long trip down the ICW to Florida from the Chesapeake with a 3-blade fixed prop, I fitted a 3-blade MaxProp to my boat in 1991. The differences were immediately apparent.

1. Feathering props like the MaxProp actually INCREASE your power and control in reverse. The difference is dramatic. Ask any owner who has tried both fixed and feathering props.

2. Feathering props aren't just for racers. Many cruisers, like me, use them happily and successfully.

3. Not all cruising boats are slugs. It's nice to have a powerful 3-blade prop which doesn't create much drag when underway.

4. Designs such as the MaxProp are virtually trouble-free and require very little maintenance.

5. Feathering props such as the MaxProp can be adjusted for pitch to get just the right balance for your engine and your boat.

The downsides are two:

1. They are costly; and

2. They won't improve your performance in forward over a fixed prop.

IMHO, the advantages far outweigh the disadvantages.

Bill
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Old 02-08-2011, 05:07   #20
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Re: Any Opinions on Max Props for a 47' Sailboat ?

i totally concur with btrayfours,i have 21" max prop on our 63 footer and 150 hp engine great in fwd or reverse,and no drag whilst sailing.

the only reason i would change to a conventional would be so i could fit a shaft alternator for power generation under sail....
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Old 02-08-2011, 09:27   #21
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Re: Any Opinions on Max Props for a 47' Sailboat ?

I have a two blade prop and it works fine in forward and reverse. I can't imagine what the benefits to my sailing style would be. I would not be motoring in the ditch and don't back into slips. I don't even go forward into slips but once a year maybe for winter storage.

My backing is to kick the stern in when I come alongside a fuel dock or maybe to set the anchor... which I rare do under power. And this works a charm.

My prop seems to line itself up with the skeg and log - no strut and exposed shaft and so it presents very little drag.

No advantage for me... your mileage may vary...
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Old 02-08-2011, 10:10   #22
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I replaced a three blade fixed prop with a three blade maxprop on my Stevens 47. It made a huge improvement in handling the boat in reverse.

Doug
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Old 02-08-2011, 10:16   #23
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Re: Any Opinions on Max Props for a 47' Sailboat ?

The Max prop on my Passport 47 worked impeccably. Much better reverse for docking. Is it worth the money...debatable... if you sail in light air...yes, if you motorsail in light air..maybe no!
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Old 02-08-2011, 10:25   #24
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Re: Any Opinions on Max Props for a 47' Sailboat?

Quote:
Originally Posted by compdoc View Post
this my first post. My new [to me] Norseman 447 AC w/ Maxprop walks uncontrollably to stbd in reverse at any speed with or without gear in reverse or neutral. Doesn't matter if helm is neutral or to port. So bad that I'm considering a bow thruster. Any suggestions?
I like to use the walk of a particular boat to advantage when I can. When starting from a dead stop, helm neutral, put it in reverse for a few seconds at idle and then take it out. This gets the boat moving. Do this again if necessary. Once the bow clears any obstructions, use a surge of Forward Thrust then neutral to turn, or a surge of reverse walking then neutral to turn, either with the helm at the correct position. It's a bit of an art, but very satisfying once you get it down. Is this what you meant? Hmmm.... all boats I've had have walked to port....
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Old 02-08-2011, 20:22   #25
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Re: Any Opinions on Max Props for a 47' Sailboat ?

Obviously the main advantages mentioned here are not relevant to the type of sailing and cruising I do.... very little light wind work and no getting in and out of slips. When the bottom is clean my boat seems quite slippery and sails well even in light air with the 2 blade prop shown in the previous post. While backing is important at times, for me they are so few and far between it does not warrant the expense.
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Old 02-08-2011, 22:27   #26
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Ok I get it is better in reverse. But I am doing fine maneuvering with my fixed prop. I am more interested in the gain in speed sailing . Can the users guesstimate what the gains in sailing speed are?
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Old 03-08-2011, 02:41   #27
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Re: Any Opinions on Max Props for a 47' Sailboat ?

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Ok I get it is better in reverse. But I am doing fine maneuvering with my fixed prop. I am more interested in the gain in speed sailing . Can the users guesstimate what the gains in sailing speed are?
i would think the speed gain would be between .2 to.5 of a knot,if not more in light winds.

try towing a bucket or full water container behind the boat when under sail and watch the gps to give you an idea of the drag factor....
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Old 03-08-2011, 05:24   #28
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Re: Any Opinions on Max Props for a 47' Sailboat ?

Towing a bucket of water is equivalent to a non folding prop? Are you serious?

My prop pictured below does not present the resistance/friction of a towed bucket of water. That's pure nonsense.

A folding or feathering proper for sure presents a smaller profile and less friction/resistance... but one also needs to consider the weight of the boat and its momentum... when considering the effect of drag from a prop.

The speed improvements apply:

mostly to lighter boats
bottoms which are clean and not foul
light air and calm seas where every bit of resistance slows boat speed

Consider what the increase and speed means to what you are doing.

If you are racing, and in light air, by all means reduce drag. If you are cruising a big heavy yacht with a non perfect bottom the improvement may be negligible.

Backing may be an issue but that is also dependent on the hull form, keel config, rudder config...and not all combinations of the above will benefit in backing from a feathering or folding prop... compared to WHAT other prop?

There is no one size fits all answer to this question.
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Old 03-08-2011, 10:36   #29
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Re: Any Opinions on Max Props for a 47' Sailboat ?

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Towing a bucket of water is equivalent to a non folding prop? Are you serious?

My prop pictured below does not present the resistance/friction of a towed bucket of water. That's pure nonsense.

A folding or feathering proper for sure presents a smaller profile and less friction/resistance... but one also needs to consider the weight of the boat and its momentum... when considering the effect of drag from a prop.

The speed improvements apply:

mostly to lighter boats
bottoms which are clean and not foul
light air and calm seas where every bit of resistance slows boat speed

Consider what the increase and speed means to what you are doing.

If you are racing, and in light air, by all means reduce drag. If you are cruising a big heavy yacht with a non perfect bottom the improvement may be negligible.

Backing may be an issue but that is also dependent on the hull form, keel config, rudder config...and not all combinations of the above will benefit in backing from a feathering or folding prop... compared to WHAT other prop?

There is no one size fits all answer to this question.
Yeah, spending that much on a prop for a wee gain in speed is not for everyone. I've questioned why I did it myself at times..
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