Folding/Feathering Props for Cruisers?

[propellanttech]

I'm looked at the forums, but I haven't found exactly the answer I was looking for. I've been debating this for some time, so I want your choice/opinion.

I define a cruiser as someone who spends 6 months to a year living on their boat (every year). Most of the time they are away from their home port.

Based on that:

Why or why didn't you choose a folding/feathering prop.

1. Cost
2. Performance
3. Maintenance

I know there are many reasons but these would be the major three.


If your not a cruiser, it is important to state your not. I'm looking at this from a cruisers point of view.


James L

[Jeannius]

I chose KiwiProps feathering props when I moved aboard full time. They were relatively cheap and gave me the increase in light wind sailing performance I was looking for.

However, when I was doing a circumnavigation as part of an organised rally, the props started vibrating after about 6000 nm and upon inspection the blades had worn and moved up the shaft causing an imbalance. Sent them back under warranty and was told they had collision damage ( they hadn't. One had had a fishing line wrapped round it ) and wanted to charge me $600 for new units. I declined and went back to fixed blade.

[propellanttech]

Originally Posted by Jeannius

I chose KiwiProps feathering props when I moved aboard full time. They were relatively cheap and gave me the increase in light wind sailing performance I was looking for.

However, when I was doing a circumnavigation as part of an organised rally, the props started vibrating after about 6000 nm and upon inspection the blades had worn and moved up the shaft causing an imbalance. Sent them back under warranty and was told they had collision damage ( they hadn't. One had had a fishing line wrapped round it ) and wanted to charge me $600 for new units. I declined and went back to fixed blade.

Thanks Mike for your point of view. That sucks the manufacturer didn't stand behind their product. Did you see a large drop in performance, with the fixed prop?

James L

[djmarchand]

James:

Well, I was a cruiser having cruised and lived aboard for most of the year. But I did have a cat with twin engines and that probably adds 50% to the performance benefit of a monohull.

So to answer your question:

Fixed Feathering

Cost Base +$4-8,000
Performance Base + 1/2-1 kt sailing
much better reverse power
Maintenance Almost none +$500-1000/yr

I base the maintenance number from the requirement to yearly grease the feathering prop and replace the expensive hub zinc which at best requires a quick haul. And these props require factory rebuilding every ten years or so to replace bearings and seals.

My comments are based on a feathering prop. I don't much like folding props- not much power in reverse, but the cost and maintenance numbers should be comparable to a fixed prop

David.

[propellanttech]

Originally Posted by djmarchand

James:

Well, I was a cruiser having cruised and lived aboard for most of the year. But I did have a cat with twin engines and that probably adds 50% to the performance benefit of a monohull.

So to answer your question:

Fixed Feathering

Cost Base +$4-8,000
Performance Base + 1/2-1 kt sailing
much better reverse power
Maintenance Almost none +$500-1000/yr

I base the maintenance number from the requirement to yearly grease the feathering prop and replace the expensive hub zinc which at best requires a quick haul. And these props require factory rebuilding every ten years or so to replace bearings and seals.

My comments are based on a feathering prop. I don't much like folding props- not much power in reverse, but the cost and maintenance numbers should be comparable to a fixed prop

David.

David,

I'm in your group about folding props, but wanted to include them here.

James L

[Stumble]

We had a maxi for years, and just installed an autostream (on a different boat). The major justification was speed under sail, where a feathering prop can easily add a knot or more at low speeds, and because they reverse there is a lot more control of the boat in reverse.

[propellanttech]

Originally Posted by Stumble

We had a maxi for years, and just installed an autostream (on a different boat). The major justification was speed under sail, where a feathering prop can easily add a knot or more at low speeds, and because they reverse there is a lot more control of the boat in reverse.

But you didn't state if your a cruiser or not. A cruiser may not want the added maintenance associated with the feathering prop. Cleaning could be a problem, as well as replacing the prop on the shaft if it came off for some reason.

Hence the reason for the specific thread geared towards cruisers who are living aboard away from their home port.

Not to be negative, just trying to keep the thread poised.

James L

[sailorF54]

I have done 8000 NM with a (single) feathering prop... but I'm not a cruiser according to your definition. So I won't speak up...

[propellanttech]

Originally Posted by sailorF54

I have done 8000 NM with a (single) feathering prop... but I'm not a cruiser according to your definition. So I won't speak up...

Please, do. Every opinion is important. It is just important to state your use of your vessel.

A person who races a lot, will have an opinion, but a cruiser may not feel the same. Still the racer may provide information to the quality or support of the manufacturer of his choosing. Everything is pertinent, as long as we know the use of the item.

I'm not trying to be a thread Nazi......just want complete information.

James L

[Bash]

Originally Posted by propellanttech

I'm not trying to be a thread Nazi......just want complete information.

Maybe just a cruiser Nazi? Your definition of a cruiser as "someone who spends 6 months to a year living on their boat (every year)" combined with the insistance that that they not be racers and that "most of the time they are away from their home port" seems to have been designed precisely to exclude.

How such elitism is supposed to provide "complete information" escapes me. However, I would remind you that just because you've started a thread on this forum doesn't mean you own it.

[propellanttech]

Originally Posted by Bash

Maybe just a cruiser Nazi? Your definition of a cruiser as "someone who spends 6 months to a year living on their boat (every year)" combined with the insistance that that they not be racers and that "most of the time they are away from their home port" seems to have been designed precisely to exclude.

How such elitism is supposed to provide "complete information" escapes me. However, I would remind you that just because you've started a thread on this forum doesn't mean you own it.

Wow, Bash as a CF adviser you are opinionated about information dissemination.

A person who cruises typically uses items which give more use than their maintenance requires.

I didn't say a cruiser can't not race. I said a racer which typically is a person who does more racing versus cruising, has their own reasons for using a speed promoting device, versus a cheaper approach.

Elitism wouldn't even want others to speak, as their information would be excluded from the mix. I however stated the thread was started for cruising use, therefor for the purpose of cruising. There are many threads comparing folding/feathering props, there need not be another just for comparison.

You speak of elitism, but there are many who complain about not using the search function of this forum.

Please, make up your mind which way you want this forum to work. It also surprises me when you get your panties in a bunch from me trying to compile information on a subject which doesn't seem to be here. Very interesting from someone who is an "advisor".

James L

[sailorF54]

Originally Posted by propellanttech

It is just important to state your use of your vessel.
.... Everything is pertinent, as long as we know the use of the item.

James L

4 seasons of summer cruising (e.g. French Brittany - Scotland and back) with a Kiwiprop: Boat is 36 ft, 6.5 tons, 27 hp Volvo
Initial Cost: by far the cheapest on the market, cheap spare blade
Performance: lightweight, so low level of vibration; pitch is easy to fine tune (I had too, as the factory setting did not allow the engine to reach max rpm) but requires haulout in practice. Efficiency in reverse makes docking in and out easy.
I cannot comment on speed gain, as I fitted it immediately I bought the boat.
Maintenance
Mine seems in very good condition: no dent, no crack. I push grease in it once a year during haulout, and sand it VERY carefully to remove all tiny barnacles etc..Easy to remove: I have to to replace the anode on the saildrive.
Maintenance costs have been minimal (I haulout my boat once a year anyway to clean/paint the bottom)
(and I was sorry to read that Jeannius had problems)
----------------
A comparative test in a French mag (in French infortunately) found that feathering props are somewhat less efficient than folding props (less miles per gallon (km per liter !) at same speed) as the blades cannot be cupped to a large extent, about 10-15%. Clear winner was Autoprop, much more expensive.
http://www.bomarine.net/index.php/do...pril-2009.html

BTW, good technical stuff by N. Calder here
http://www.hymar.org/upload/BMEA_211009.pdf
http://www.hymar.org/upload/LIBS_130110.pdf

[sailorboy1]

My last boat had a Max-Prop 3 blade. It worked fine, but it needs to be greased.

When I got my current boat I wanted to replace the fixed prop and read every test article I could find, including the one in French because graphs are graphs. Based on the that I got a Flex-O-Fold 3 blade based on price/performance/no maintance required.

[Jim Cate]

G'Day James,

1. We have been full time cruising since 1986.

2. On our previous boat we started out with a two blade Martec Elliptic folder. Excellent performance in forward, poor in reverse. Minimum drag when sailing which is important to us. No maintenance was required beyond normal cleaning and antifouling. No additional anodes required. After circa 25,000 miles it needed to be rebuilt for the pivot pins and blade sockets were badly worn. After circa 50,000 miles it was worn to the point of needing another rebuild, and we replaced it with a three blade Autostream feathering prop.

The feathering prop had roughly the same drag sailing, and much better thrust in reverse as expected. What we didn't expect was a ~25% loss of fuel economy, due to the inefficient flat blade design that all feathering props must have. That boat had small tanks, and the loss of economy was a significant loss of motoring range. That prop required greasing periodically, but that could be done in situ via a grease nipple. It came with a proprietary anode that was short lived and expensive. We eventually realized that the shaft anode seemed to protect the prop adequately, and stopped using the one on the prop with no bad results. We sold the boat having put some 35,000 miles of cruising on the feathering prop and it was still in good shape. IMO the Autostream design is superior to Maxprop (at least the ones that were available at that time) and at least here in Oz, are far less expensive.

3. Our current boat came with a badly worn Gori two blade folder. The PO had it rebuilt at the time of purchase, but the work was poorly done, and the prop failed soon thereafter. After some research we replaced it with a three blade Flex-O-Fold folder. We considered the elegant Gori folder, but it was more than double the price of the FOF. The sailing performance of the FOF is excellent, the performance in forward is excellent, and it is surprisingly good in reverse. Maintenance is disassembly and greasing when slipped for antifouling. Takes me about an hour. With a minor modification to the hub I am able to use inexpensive generic "button" anodes on the prop. We now have 42,000 miles and ~2800 engine hours on the prop and there is no noticeable wear.

IN summary: we require the improved sailing performance afforded by some sort of non-fixed prop. Both folding and feathering props will provide this improvement. Folding props are significantly less expensive than feathering. The only advantage of feathering props is greater thrust in reverse. In our sailing experience, this advantage is not enough to counterbalance the inevitable loss of efficiency from the flat blades to say nothing of the price differential.

I hope that this helps clarify your thinking!

Cheers,

Jim

[Srah 1953]

Originally Posted by Don Lucas

My last boat had a Max-Prop 3 blade. It worked fine, but it needs to be greased.

When I got my current boat I wanted to replace the fixed prop and read every test article I could find, including the one in French because graphs are graphs. Based on the that I got a Flex-O-Fold 3 blade based on price/performance/no maintance required.

Hi Don
Two questions, if I may-
Does the Flex-O-Fold not need any maintenance at all, no greasing or anything?
How have you found performance in reverse?
Thanks