feather or fold

[Ridax]

You got it. You cannot reduce the drag by any more so 10 out 0f 10. A good modern folder will propel the boat at hull speed, so again 10 out of 10. I never go far in reverse, into or out of a berth perhaps? How far do you want to go in reverse? A folder does the job, it works, why give it anything less than 10 out of 10? It does the job.

By that attitude everything works as well as anything else. A feather prop will also get 10/10.

Performance in reverse is not just a matter of how far you go in reverse. It is a matter of how fast you can stop. How good the propeller is in forward is not just a matter of reaching hull speed, but how much fuel you use to do it.

If you had been talking about cars, your way to think would be "the brakes are not important because eventually it will stop anyhow and fuel consumption and engine performance is not important because anyhow the car will reach the speed limit".

Do you think the same way when you select sails? It doesn't matter what kind of sails or how old sails you have, because anyhow the boat will reach hull speed if the wind is sufficient and with a suitable direction.

Why at all use the points 10/10 when you are not prepared at all on judging on how WELL it does the different tasks?

 

[bignick]

Perhaps a binary scoring system would be more appropriate?

 

[wiggy]

I don't get the why it's important to be able to stop your boat in a fraction of a second, I have never used reverse to stop my boat in a hurry, marbe people don't keep a good watch or go too fast in confined waters.

 

[phantom18]

out of the choices i prefer folding to avoid drag and lobster lines BUT i was more impressed with a friends variable pitch.......loads of cash but very good.

 

[Ridax]

I don't get the why it's important to be able to stop your boat in a fraction of a second, I have never used reverse to stop my boat in a hurry, marbe people don't keep a good watch or go too fast in confined waters.

Most things can be solved in different ways. I think they even managed without propellers (and even without engines) some time ago

But there are situations when good stopping performance could be a benefit and it doesn't have to necessarily be panic situation. You could have a heavy side wind that make your boat drift in which case a good forward speed will help, which in turn would require good stopping performance if in a docking situation.

 

[Elemental]

I don't get the why it's important to be able to stop your boat in a fraction of a second, I have never used reverse to stop my boat in a hurry, marbe people don't keep a good watch or go too fast in confined waters.

For me, good reverse performance is an indication of a good design. However, I agree that the power available in reverse isn't critical - I'm more interested in a prop's ability to mitigate propwalk, which is important when manoeuvring. My current fixed three blader produces very pronounced propwalk - fine if it's in a helpful direction but a b****r otherwise.

 

[Frankie-H]

Feather aligns blade with water flow reducing drag, folding collapses thus reducing drag

Now you know that's not true jimi. This has been discussed many times before and, I think, it was proved last time or the time before, that it might cause more drag. Not that drag is necessarily always a bad thing

 

[jimi]

I don't get the why it's important to be able to stop your boat in a fraction of a second, I have never used reverse to stop my boat in a hurry, marbe people don't keep a good watch or go too fast in confined waters.

Helps with berthing manouvres

 

[Tranona]

Helps with berthing manouvres

Yes, suggest Wiggy comes with me when I am getting my Bavaria in and out of my tight berth. I can say with confidence the FlexoFold is as good as the fixed 2 blader it replaced - important consideration in the decision to fit. Reliable astern handling also important in the boat's previous life in Greece - backing up to quays each night - good stopping essential.

 

[jimi]

Yes, suggest Wiggy comes with me when I am getting my Bavaria in and out of my tight berth. I can say with confidence the FlexoFold is as good as the fixed 2 blader it replaced - important consideration in the decision to fit. Reliable astern handling also important in the boat's previous life in Greece - backing up to quays each night - good stopping essential.

When backing up to a quay, putting it in forward is often more effective than astern for stopping purposes ;-)

 

[Tranona]

Yes see now that my first comment was confusing. Going backwards reliably is important.

 

[snooks]

You could have a heavy side wind that make your boat drift in which case a good forward speed will help, which in turn would require good stopping performance if in a docking situation.

Then you use warps to slow you down, don't rely on the engine.

I did once, and the walkway pontoon still has antifoul from the forefoot (but it's now hidden under one of those pontoon fenders ). I realised then that the 20 hp Bukh with a 2B fixed in our new boat takes time to rev up and stop and my Sadler has more displacement than most modern boats.

It's a mistake you only make once.

After living with it for the last 3 seasons we don't use the engine to stop from speed, because we don't go faster then we can stop in a short time.

Of course once we launch with a new 30hp Beta and a new 3B flexofold, it's likely I'd loose my wife off the foredeck if I were to do a crash stop!!

 

[Ridax]

Then you use warps to slow you down, don't rely on the engine.

Warps? Around what? And why would it be wrong to rely on the engine for doing a stop? There are plenty of times that you are relying on the engine, forward or reverse doesn't matter. It doesn't necessarily mean there is a disaster if it fails, but there is no reason to not use it when it works, but of course should be prepared for how to act if it fails.

 

[snooks]

Warps? Around what? And why would it be wrong to rely on the engine for doing a stop? There are plenty of times that you are relying on the engine, forward or reverse doesn't matter. It doesn't necessarily mean there is a disaster if it fails, but there is no reason to not use it when it works, but of course should be prepared for how to act if it fails.

Warps = bits of rope you use to park, manoeuvre or secure your boat

Used around cleats (horns usually found at the end of pontoons) and when surged out can slow a vessel nicely without having to to put the engine in reverse.

If you're barrelling towards a pontoon at speed and planning to use the engine to stop quickly, and it doesn't (stuck in gear, prop comes off, stalls, gear cable brakes, fouled feathering propeller etc etc).....Then what?

How would you act if you engine fails now? Strong wind, you need speed to manoeuver, say 4 knots into a short finger berth with less than a boat length to stop the boat. You have your bow into the berth, into neutral, into reverse...Nothing...You have about 12 seconds to come up with a solution...crunch too late

If you plan to use the warps to stop, then you don't have to rely on the engine. Simples

If you fudge up the warps you could use the engine
If you just rely on the engine and it won't stop you, you sire, is Donald ducked

My point is to have a back up plan, the engine is my back up plan, not my only plan.

 

[Ridax]

Warps = bits of rope you use to park, manoeuvre or secure your boat

Used around cleats (horns usually found at the end of pontoons) and when surged out can slow a vessel nicely without having to to put the engine in reverse.

I don't know what it looks like where you are manouvering, but here we don't have cleats or horns growing like mushrooms on every island and even if approaching a harbour, you go straight in towards the berth, so I don't see at what point (and to what) you are attaching those warps. Actually at a total loss of what you mean. Maybe you are only used to approaching marinas...

You do as you want and I do as I want. I am not going to act like the engine will fail everytime I use it. I just plan so there is no disaster if it does fail.

If you plan to use the warps to stop, then you don't have to rely on the engine. Simples

So, if you have those warps to stop, why would it be a problem for me to use the engine to do the stop and just have the warps as emergency? Regardless of which way you see it, you benefit from good reverse performance. That I use the engine to stop doesn't mean that I am helpless if it does. I just enjoy the stopping power when it works (which has been 100% of the times so far with the feathering prop).

 

[tri39]

I must say one of the benefits of my Kiwi prop is it's great stopping power!
Allied to a gearbox with a higher ratio in reverse of course.
My boat was hopeless in reverse b4 I fitted the Kiwi prop, it was a revelation.

And to those who think the blades flop over in reverse, they do, BUT the rollers push them back again, to a coarse pitch.

 

[Sailfree]

Warps = bits of rope you use to park, manoeuvre or secure your boat

Used around cleats (horns usually found at the end of pontoons) and when surged out can slow a vessel nicely without having to to put the engine in reverse.

If you're barrelling towards a pontoon at speed and planning to use the engine to stop quickly, and it doesn't (stuck in gear, prop comes off, stalls, gear cable brakes, fouled feathering propeller etc etc).....Then what?

How would you act if you engine fails now? Strong wind, you need speed to manoeuver, say 4 knots into a short finger berth with less than a boat length to stop the boat. You have your bow into the berth, into neutral, into reverse...Nothing...You have about 12 seconds to come up with a solution...crunch too late

If you plan to use the warps to stop, then you don't have to rely on the engine. Simples

If you fudge up the warps you could use the engine
If you just rely on the engine and it won't stop you, you sire, is Donald ducked

My point is to have a back up plan, the engine is my back up plan, not my only plan.

Try that in Cherbourg with only D shaped hoops at the finger pontoon end. Cleats are at the bows!!

Personally I like the ropes /warps on board until the prop has stoped and when leaving a berth don't put it in gear until I have heard the cry rope inboard from my crew. Mix up ropes and props and it can spoil your day.

I have often thought of using a rope but from the bow it would swing the stern out on a stop and from the mid cleat if you missed dropping it over the cleat it fits immediately round the prop!!

Often when its blowing hard its necessary to go in fast on any production boat - high sides-windage. For that reason on my 43 I have a bow thruster (that I try not to use) and a feathering prop. Reduces the risk of having to exchange insurance details with the adjacent boat!!

 

[snooks]

Actually at a total loss of what you mean. Maybe you are only used to approaching marinas...

Cleat, at the end of a finger pontoon:

Not my boat, pontoon, or way of using a cleat

My home berth is a marina berth on the south coast of the UK, but I've travelled far and wide, so I'm not "only used to approaching marinas"

The technique I use to get into my finger berth (in a marina) is to take a long warp from my midships cleat, and out over the toe rail/under the guardrail to form a big loop [edit - Not big enough to reach the prop], this comes back over the toe rail/under the guardrail around the front of the midships cleat and back to a primary winch.

All I, as skipper, have to do is get close enough to the end of the pontoon (where you'll usually find a cleat -unless you're in a French marina with either nothing or a ring at the end), my crew holds out the warp, it catches on the horn of a cleat, I put the engine back to tickover (still in forwards), surge out the warp from the primary winch until we're stationary. I put the helm over so the engine is pushing the stern in and fix it there.

The boat will stay happily in position until the warp is released or the engine is taken out of gear.

In this situation we don't need to use reverse.

If you have a reliable engine I'm happy for you, but not every engine is always reliable, and unless your engine has bitten you on the bum, it's easy to have an unwavering trust in them. Sadly mine has bitten me on the bum...a number of times while cruising Scotland. Our engine became unreliable, sometimes without warning. It would stop when going into neutral - Fun when you're manoeuvring into or out of a berth at speed in a breeze!

As long as you have a back up plan, you're at least one step ahead of someone without one

 

[PeterMcK]

Forward Efficiency

I've had a quick skim over this thread so apologies if I missed anyone else saying this but ... a well designed folder should be more efficient than a feathering prop. A blade should be twisted, tip to root, so that the apparent angle of attack is constant, taking into account the difference in tangential velocities for each radial section. Feathering blades have to be flat, folders don't, so they're always a compromise in this respect.

This matters. Any sacrifice of efficiency simply goes into unseen churning of water, burning of pound notes and loss of range between fuelling stops.

Not that I'm saying that all folding props are efficient. My Radice is adequate, excellent for sailing and racing, but with its fairly ugly profile is obviously going to be inefficient motoring. The fixed three blade it replaced consumed about 70% as much fuel, maybe even less. Having said that, it will drive the boat at near hull speed - I've a big engine and power to spare/waste. Stopping is absolutely not a problem. And it backs up in a straight line straight away, something the three blade would never do.

However, the comparitive tests in YM(?) a couple of years ago produced hugely impressive results for the flexofold which really does look the part. I've recently re-engined and, having an extra 20% of torque to play with, I intend to use this an excuse to get a new flexofold and go up a couple of inches in pitch. Given the apparent performance and efficiency of the flexofold, I see no point in having either fixed or feathering props on a sailing boat.

 

[maxi77]

It does make me chuckle a bit when people talk about how great a Kiwi is at reversing. My main concerns when buying a prop, are 1. How does it cope in reducing friction when sailing (it is a sailing boat after all) folder: 10/10 . 2. does it do a good job in driving the boat forward. (Flexofold) sometimes I need to motor and when I do It want to be able to motor at the highest speed with the lowest revs. Folder: 10/10. 3. Every now and again, (2% of boat use?) I need to reverse, does my prop go in reverse? Yes 10/10 (A folder is not the best in the world, but you'll get used to it)

So if you are using your boat for sailing with some motor sailing, you want good value, you dont want complicated mechanics, get a folder! If however, you do a lot of going backwards a Kiwi may just be the answer.

Having had both folder and featherer on balance the featherer is better, because it functions at it's best in all three funtions, sailing, forwards and astern. Many featherers also allow pitch adjustment which is quite useful if the previous owner got his calculatins wrong, where as if it is a folder it is yet more expense.

I certainly found my featherer a J Prop very good