Anyone got anything bad to say about feathering/folding props?

[Oscarpop]

Ok, so heres my thoughts....

I am toying with the idea of having a feathering prop put on the new boat.
I had a folding one on the last one,and loved it, but never experienced a fixed, so have no comparison.

Now the feathering prop manufacturers will tell you " half a knot extra", " a fixed prop is like dragging a bin lid about"

But they are obviously going to say that.

I figure that owners who have just spent £2000 will also say the same.

So before I go and spend a chunk of money on one, can anyone tell me otherwise?

Will a feathering prop really make that much difference to a freely spinning fixed?

I'd like someone to apply science to this as I'm not sure that the difference is going to be that great.

 

[sailorman]

Ok, so heres my thoughts....

I am toying with the idea of having a feathering prop put on the new boat.
I had a folding one on the last one,and loved it, but never experienced a fixed, so have no comparison.

Now the feathering prop manufacturers will tell you " half a knot extra", " a fixed prop is like dragging a bin lid about"

But they are obviously going to say that.

I figure that owners who have just spent £2000 will also say the same.

So before I go and spend a chunk of money on one, can anyone tell me otherwise?

Will a feathering prop really make that much difference to a freely spinning fixed?

I'd like someone to apply science to this as I'm not sure that the difference is going to be that great.

as for alleged extra performance check-out racing handicaps that will give the definitive answer.

i have a MaxProp thats probably 20 yrs old.
would i have another yes without doubt

 

[scottie]

Kiwi prop.

We have just relaunched for 8th season.
We have a kiwi prop fitted from new service consists of greasing blade pins and hub.
We change the anode each year mainly due to the ropecutter being located by a pin in the zinc and looks flimsy plenty left in the body of he zinc.
There is minimal if any wear in the prop body or blades and none in the spline!
From professional experience most folding props would have some wear in his time and any other sail drive prop would have definite wear in the spline!
In addition it does it's job .

 

[samwise]

A bit like anchors, everyone has their favourite, but for my pennorth I would recommend the Darglow Featherstream which, as its name suggests in a featherer. We have had two seasons with it and it has made a substantial difference to our sailing performance. Not much improvement in ahead, but then we have a modest 18hp Volvo. Astern performance and stopping power however is much improved.Good value too. I'd buy another

 

[Tranona]

The downsides are cost and potential maintenance problems, including rapid anode erosion. However, these depend to an extent on the design you choose.

The reductions in drag are real - there is plenty of evidence of this. What is less clear is whether the reduction in drag under sail translates into improved performance - or perhaps the amount of improvement is not so predictable. Logically improvements occur in light airs where drag has a bigger impact on speed, reducing as wind increases. So, if you expect a lot of sailing in light airs you may see more benefit. The reduction in drag varies very little from design to design, although there are some very low drag 2 blade folders that probably have less drag than others.

You also need to consider motoring performance as this varies considerably from design to design as you will have seen from the tests of a range of props in YM. Reverse performance also can vary and some designs allow the setting of the pitch to be different in forward and reverse. Other designs vary the pitch according to load which can improve motoring performance, particularly when motorsailing. So, again if you anticipate a lot of motor sailing (for example in the Med when there are often long periods of light wind and you still want to make progress) this may be a benefit you will value.

So, as always there is no simple answer to what seems a simple question. You need to do your research, decide what your priorities are and make your choice

I have two boats - one a heavy long keel boat with a low hp engine. The other is an AWB with adequate engine and a saildrive. On the former I have a large diameter low pitch feathering prop with a coarser pitch reverse. Forward motoring is similar to the fixed prop, reverse superior and lower drag under sail. On the AWB I have a 2 blade folder of the most simple type which performs virtually identical to the fixed prop but definitely lower drag in light airs. I think if I were back in the Med permanently I would consider a self pitching prop - but it is nearly 3 times the price of the folder!

 

[Slipperman]

Have had a Kiwi prop for 6 seasons and it has been brilliant. Cost under a grand and so long as you keep it lubricated it does what it says.

 

[Bosun Higgs]

Ok, so heres my thoughts....

I am toying with the idea of having a feathering prop put on the new boat.
I had a folding one on the last one,and loved it, but never experienced a fixed, so have no comparison.

Now the feathering prop manufacturers will tell you " half a knot extra", " a fixed prop is like dragging a bin lid about"

But they are obviously going to say that.

I figure that owners who have just spent £2000 will also say the same.

So before I go and spend a chunk of money on one, can anyone tell me otherwise?

Will a feathering prop really make that much difference to a freely spinning fixed?

I'd like someone to apply science to this as I'm not sure that the difference is going to be that great.

I once owned a Prout cat with a Sillette drive leg sporting a 3 blade prop. The difference between sailing with the prop in the water ( still or rotating) and sailing with the leg and prop lifted out was a consistent half to three quarters of a knot. A cat is designed for low drag so it will be a bit more sensitive to extra drag but I could believe half a knot on a mono.

However, the PY handicap system is performance based and that makes an allowance of 4% going from and outboard which can be lifted to a 3 blade prop. At 6kn that is 0.25kn.

 

[tri39]

Another vote for Kiwi props.
At least 0.5kt improvement in sailing speed especially in light airs.
Also much more powerful in reverse with a higher pitch that really aids close quarter manoeuvring. I find mine does rotate unless put in gear. And I think 55HP is the limit.
They're also cheaper than the competition.

 

[tv1]

Feathering Prop.

My original issue 12" diameter 3-blade fixed prop was a compromise between motoring thrust and sailing drag, so was not especially good in either circumstance. I changed it for a 17" Featherstream (no room for a bigger one) and it has transformed the boat, a MacWester Wight 30' ketch. Now get much more punch into a Solent chop, much less drag when sailing, no turbulence over the rudder and much more stopping power and astern power, with less propwalk. Close quarter handling is so good I can make the old girl perform like a young ballerina! The manufacturer did all the calculations for my engine type, waterline length and displacement, and came up with the right combination of diameter and pitch so that fully open throttle allows max rated rpm. But if they don't get it exacrly right first time they will adjust the pitch for you, to ensure you don't waste fuel or overheat.

 

[Sybaris]

I would recommend the Darglow Featherstream

Me too. In addition to Darglow being a very nice company to deal with here are the advantages I have noticed with one season of usage (note we have two engines, shafts, and props so for us the advantages are even bigger but the price is also doubled):

Sailing:
- Much more speed and response in light wind
- More speed in strong winds
- Less drift in light winds
- Port tack was always better before, now they are the same and my theory is that the free spinning props pulled the boat slightly on stbd tack
- The stern does not pull as much left and right when going downwind in strong following sea (again the free spinning props must have pulled quite strongly when surfing)

Motoring:
- Quicker start (take off) when going forward
- Much quicker start when going astern
- Much easier to maneuver the two engines in tight situations (marinas etc.) at slow speed (one back and one fwd for example)
- Better breaking force
- Much less prop walk

The fuel consumption has increased by around 3%

Cheers,
Per

 

[mustntgrumble]

Feathering prop?

Get one

After 3 seasons (Darglow Featherstream) yes it does actually do what it says on the tin, but for practical sailing I found the most important difference is that I now Sail in (light wind) conditions where previously I would have Motored.

And yes Darglow are nice people to deal with

 

[nimbusgb]

Your Question - Does anyone have anything bad to say about feathering/folding props?

Yes, they're expensive.

But all the other stuff is good. I love my kiwiprop

 

[shaunksb]

" a fixed prop is like dragging a bin lid about"

.

Well yes it is but......

If you don't keep you bottom clean thats like dragging a parachute.

If you are already dragging a parachute adding a bin lid won't make any difference.

We found with ours it was great just after she was put back in but after a few months in the water the difference falls away.

So, if you race and wipe your bottom regulary then it's the dogs whatsits.

If you cruise and aren't too fussy and don't make a lot of long passages then you won't notice a lot of the time.

We also found more vibration with our (folding) prop but it was considerably heavier than the standard two blade and I got through a few cutless bearings too.



____________

 

[GrahamM376]

Get one

After 3 seasons (Darglow Featherstream) yes it does actually do what it says on the tin, but for practical sailing I found the most important difference is that I now Sail in (light wind) conditions where previously I would have Motored.

And yes Darglow are nice people to deal with

Another vote for Featherstream. We went from 2 blade fixed to 3 blade feathering and it made a big difference. About 1 kt gain at low speed sailing, under power much better bite into chop & headwind and, less astern prop kick so easier to steer.

 

[savageseadog]

Less turbulence on the rudder and less likely to broach as well as the other merits, If you sail then it's a no brainer.

 

[Neil_Y]

I've sailed many 000's of miles with a fixed two and three bladed as well as raced and cruised with folding props.

When cruising we almost always towed an aquair and were never concerned with a lack of performance, I preferred the fixed for manoeuvring, which is when you need the engine. There is a huge difference in types of props and how they behave with a quick astern to stop the boat, that's what I missed with a volvo folding prop on a sail drive, the delay seemed a bit random once the prop had some fouling.

If I had to choose I'd go for fixed, for simplicity, reliability and known power. I may be biased against folders as I had a very bad experience when a folder refused to unfold when I wanted some astern in a tight docking situation in strong winds.

I think the other comment about sailing performance is spot on, if you haven't got a very clean boat the prop can't make much difference. Cruising speed doesn't matter all that much to me, I'm out to enjoy the passage as much as the arrival.

 

[cmedsailor]

Is it true that there's a loss in motoring performance with a feathering comparison to fixed or folding due to the shape of the blades (with same rpm of course)? They need to be flat.

 

[ukmctc]

Ok, so heres my thoughts....

I am toying with the idea of having a feathering prop put on the new boat.
I had a folding one on the last one,and loved it, but never experienced a fixed, so have no comparison.

Now the feathering prop manufacturers will tell you " half a knot extra", " a fixed prop is like dragging a bin lid about"

But they are obviously going to say that.

I figure that owners who have just spent £2000 will also say the same.

So before I go and spend a chunk of money on one, can anyone tell me otherwise?

Will a feathering prop really make that much difference to a freely spinning fixed?

I'd like someone to apply science to this as I'm not sure that the difference is going to be that great.

Just remember to give yourself extra gap between you and the boat infront, if he stops quick you won't, a few seconds delay while the prop opens, same when parking up think ahead more and give more time for movements such as stopping, slowing down or going aft.
I know I can change direction quicker ie backwards or stop than the guy in the next berth, he has a folding prop mine is fixed.
Also you won't go any faster than your hull speed through the water, I would think that the manufacturer would have put the appropriate engine and gear on? and 1/2 a knot for £2000 who cares!

 

[Tranona]

Just remember to give yourself extra gap between you and the boat infront, if he stops quick you won't, a few seconds delay while the prop opens, same when parking up think ahead more and give more time for movements such as stopping, slowing down or going aft.

That is simply not true of most of the props currently on the market as shown in the YM test. It may have been true in the past of some of the poorer folding props where the emphasis was on very low drag. It is not true in general of any of the feathering props that the OP is considering, and as several people in this thread have commented, performance in reverse is often superior to that of a fixed prop. Improvements in blade design and mechanisms have improved many of the folding props to the point that reverse and stopping performance is at least as good as an equivalent fixed prop.

 

[Tranona]

Is it true that there's a loss in motoring performance with a feathering comparison to fixed or folding due to the shape of the blades (with same rpm of course)? They need to be flat.

A gereralisation, but no longer true as some of the latest designs that have shaped blades. Flat blades were used in the past because they have to operate in two planes. However, some shape is possible, or the prop can have different pitch in reverse to provide greater thrust at low revs.

As you willl see from comments here, most people buying the latest types of props report no loss of motoring performance and often an improvement.