Are folding props worth it?

[Uncle Bob]

Originally Posted by daveball

Major disadvantage(s) of a fixed prop, noise. This was solved by employing a shaft brake. I our case this consisted of a length of webbing material wrapped around the shaft and secured to a cleat. Eliminating the noise made sailing much more enjoyable. The other disadvantage was maneuvering in reverse with a full keel. Tricky to say the least.

Bet that really improves your sailing performance.

[noelex 77]

Originally Posted by cygnus

I have a 1975 Pearson 10 Meter. Yanmar 2 GM20 F Feathering prop. I was told by a prop man when sailing put her in reverse and the prop will feather vertical so there won`t be any drag.

Be aware that Yanmar advise that the gear lever should be in neutral.


“Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result. “

See here:

http://www.shaftlok.com/YANMAR_MSA08...al+Sailing.pdf

Personally I think this is probably an unnecessary precaution with a folding of feathering prop, but in most cases with these propellors (there are exceptions) a few seconds in gear (forward or reverse depending on the gearbox) is all that is needed to feather or fold the prop. After this the gear lever can be moved back to neutral conforming with Yanmar’s requirements.

BTW does anyone (especially with a 2 blade fixed or feathering prop) mark their propshaft so the blades can be aligned with the keel and P bracket? Oh those glorious racing days when a hundredth of knot was significant.

As an alternative, for cruising, aligning the blades to reduce the chance of picking up lines is perhaps worth considering (with a fixed or feathering prop).

[Pete7]

Originally Posted by noelex 77

BTW does anyone (especially with a 2 blade fixed or feathering prop) mark their propshaft so the blades can be aligned with the keel and P bracket? Oh those glorious racing days when a hundredth of knot was significant.

As an alternative, for cruising, aligning the blades to reduce the chance of picking up lines is perhaps worth considering (with a fixed or feathering prop).

Nah, the shaft is whizzing around even under sail, not putting my hands in there. Anyway the rumble and change in noise frequency from the 2 blade fixed prop is an excellent indication of speed through the water as I trim the sails.

The amount of streamlining from our P bracket must be minimal, but I get that racers will do anything for a fraction of a knot. Didn't Uffa Fox iron his sails before a race. That should be interesting with todays laminates.

[Zzmeyer]

My Yanmar SD60 saildrive manual says that you can put the gear in neutral or reverse (page 16).
"When the boat sails with engine is off,
the shift position of the sail drive can
be:
• In neutral position and in this case
the propeller is free to rotate.
• In reverse position:
• To lock the fixed propeller.
• To fold the folding propeller.
• To feather the feathering propeller."

With my flexofold I put it in reverse. My Volvo saildrive manual says put a fixed prop in neutral and a folding/feathering in reverse.

[a64pilot]

Originally Posted by noelex 77

Be aware that Yanmar advise that the gear lever should be in neutral.


“Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result. “

See here:

http://www.shaftlok.com/YANMAR_MSA08...al+Sailing.pdf

Personally I think this is probably an unnecessary precaution with a folding of feathering prop, but in most cases with these propellors (there are exceptions) a few seconds in gear (forward or reverse depending on the gearbox) is all that is needed to feather or fold the prop. After this the gear lever can be moved back to neutral conforming with Yanmar’s requirements.

BTW does anyone (especially with a 2 blade fixed or feathering prop) mark their propshaft so the blades can be aligned with the keel and P bracket? Oh those glorious racing days when a hundredth of knot was significant.

As an alternative, for cruising, aligning the blades to reduce the chance of picking up lines is perhaps worth considering (with a fixed or feathering prop).

He has a feathering prop, I’m sure the reverse is to get it feathered, of course once feathered, there is no rotational force.
Yanmar I’m sure assumes worst case which would be a fixed prop.

[FlyingScot]

It appears Yanmar feels differently about Neutral/Reverse depending on SD20 vs SD40/50. I plan to get a couple of Flexofolds, eventually for my two 3YM30/SD20s. I've bolded the part the differences. Also, I underlined the 'under 3kts' part.

TECHNICAL BULLETIN
Ref No.: YMTQTB11-017
Date: October 18, 2011
Page 1 of 2 GTB2010005
To : Yanmar Marine Regional Head Quarters and
All Yanmar marine distributors
Subjects : Yanmar Sailboat engine control lever position during sailing
under sail with engine stopped
1. Introduction
Yanmar wishes to inform you about the instruction of the control lever position during sailing under
sail with engine operation stopped. This instruction is subjected to mechanical type gearboxes and
sail drives only.
2. Operation instruction
2-1 Mechanical Cone clutch :
Applicable models: Sail Drive: Models SD 40, SD50 and SD50-4T
Marine gear: Models KM2P, KM35P, KM35A and KM4A
When mechanical cone clutch type gearbox or sail drive is equipped with the following propeller:
a. Fixed propeller:
When sailing under sail with engine operation stopped put control lever into Neutral. The output
shaft keeps rotating.
Notice:
When control lever is put in Reverse position, cone slippage will be introduced and void your
warranty and there is possibility that the clutch doesn't disengage. This can be a problem for
engine re-starting.
There are options to stop free rotation of propeller-shaft if customer doesn’t want occur noise
from rotating propeller:
1) For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
2) For marine gear: install the Shaft - Lock device, Yanmar does not supply, on the propeller
shaft.
b. Folding propeller: (including GORI Over-drive propeller)
When sailing under sail with engine operation stopped put control lever into Reverse position,
this to operate the folding propeller to fold close blade and output-shaft stops from rotating.
After this operation put the control lever back into Neutral.
c. Feathering propeller:
When sailing under sail with engine operation stopped put control lever into Reverse position,
this to operate the feathering propeller into feathering position and output-shaft stops from
rotating. After this operation put the control lever back into Neutral.
TECHNICAL BULLETIN
Ref No.: YMTQTB11-017
Date: October 18, 2011
Page 2 of 2 GTB2010005
2-2 Other Mechanical clutch:
Applicable model: Sail Drive: Model SD20, SD31 (Dog clutch type)
Marine gear: Model KBW10, KBW20, KBW21
(Mechanical single or multi disc clutch)
When mechanical dog clutch or mechanical disc clutch is equipped with the following propeller:
a. Fixed propeller:
When sailing under sail with motor stopped put control lever into Neutral. The output shaft
keeps rotating.
Notice:
When control lever is put in Reverse position there is a possibility the clutch does not disengage.
This can be a problem for engine re-starting.
There are Options to stop free rotation on propeller shaft if customer doesn’t want occur noise by
rotating:
1) For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
2) For marine gear: install the Shaft-Lock device, Yanmar does not supply, on the propeller
shaft
b. Folding propeller:
When sailing under sail with engine stopped put control lever into reverse position, this enables
the folding propeller to fold close blade and output-shaft stops from rotating. After this operation
put the control lever back into neutral or remain reverse position as you like.
c. Feathering propeller:
When sailing under sail with engine stopped put control lever into reverse position, this enables
the feathering propeller into feathering position and output-shaft stops from rotating. After this
operation put the control lever back into neutral or remain reverse position as you like.
Notice:
Do above mentioned operations with a boat speed <3knts when sailing under sail with
engine operation stopped.
Shuji Ando
Manager, Overseas Group
Quality Assurance Department
Marine Operations Division
Yanmar Co.Ltd


From the 2007 Yanmar SD20/40/50 peration manual :
Rubber bushing (Folding propeller)
For the sail-drive, be sure to use the
folding propeller which is provided with
a rubber bushing. If a propeller is used
without rubber bushing, the shaft, bearing,
and gears of the sail-drive are surely
damaged.

I'm not sure which ones don't have rubber bushings, but I understand FoF does have them.

This manual also states 16" maximum size for 3YM30 SD20 combo.

[Zzmeyer]

Seems to me a fixed prop is harder on a transmission than either a folding or feathered prop. With a fixed prop you can either lock it in reverse thereby using the transmission as a break (which both major manufacturers say not to do) or let it free wheel. The rotation, to me, will put wear on the transmission over time. Depending on make and model, there is different recommendations for feathering or folding prop. My uneducated guess is that is because it doesn't matter that much. How much difference does it make to a transmission if a prop is properly folded or feathered as neither will attempt to rotate the transmission (very much). So is it fair to conclude, a bit tongue in cheek, that a fixed prop is worse for your transmission than either folding or feathering props?

[Connemara]

Just to throw in another couple of questions:

Both of my boats have saildrives. The Wright 10 has a Volvo Penta with a fixed bowtie prop. The Mirage 27 has the old Johnson OMC Zephyr with the folding two-blade prop that was sold as an option for the motor.

Questions:

-- as far as I can see there is no recommendation in the Volvo manual for a tranny position when the engine is off. Suggestions?
-- I see some people put their folders in reverse with the motor off. Should I do that for the Zephyr?

Connemara

[Zzmeyer]

Connemara - as I've observed from the various posts the position is very much a function of the type of transmission. My Volvo 150S says to put in reverse for folding/feathering and neutral for fixed.

[Exile]

Originally Posted by Zzmeyer

as I've observed from the various posts the position is very much a function of the type of transmission.

Apparently so. My Westerbeke 82B with a Hurth transmission calls for locking the shaft in reverse when under sail with no engine. No distinction made based on type of prop. I was told it had to do with insufficient lubrication when the shaft is spinning without the engine running.

[noelex 77]

Originally Posted by a64pilot

He has a feathering prop, I’m sure the reverse is to get it feathered, of course once feathered, there is no rotational force.

This is true for the Maxiprop (which I have had) and I think most other feathering props. It is not true of the Autoprop which at least in my installation would eventually un-feather itself if the gearbox was left in neutral.

Certainly, in my case the gearbox could not be left in neutral with the Autoprop. Does leaving the gearbox in gear create a problem with the cone clutch even if there is no rotation, for example the creation of a flat spot? I have no idea, but Yanmar have experienced many problems with their sail-drives and they seem to have become more adamant concerning the importance of leaving the gearbox in neutral if the engine is not running.

I think it worth following the detailed advice posted by Chris.

[a64pilot]

Does he have a cone clutch? My Yanmar transmission has clutch packs, and near as I can tell there is no prohibition from leaving it in reverse, the manual doesn’t say, or I haven’t found it.
However my boat manual says to leave the transmission in reverse to prevent excess wear and noise.
So not all Yanmar transmission have that prohibition.

I leave mine in neutral and the Autoprop doesn’t rotate, but my shaft angle is nearly zero too, and maybe that is why. I leave mine in Neutral just because that’s where I shut the engine down, and just don’t think about putting it in reverse, but I used to with the fixed prop cause you could hear that thing whirring away if I didn’t

[Toccata]

I have an Autostream feathering prop.
This won't go into a feathered position unless the shaft can turn (I guess approx 90 degrees)
So, just stopping the shaft i.e. reverse immediately after the engine is stopped, leaves the prop in its normal drive position. After stopping the engine, the water pressure/flow on the blades is required to cause the propeller to rotate the shaft, until the prop finds its feathered position. This requires moving the gear lever into neutral.
I think the Autostream instructions call for stopping the engine while in the forward (driving) position to ensure adequate water flow over the blades to cause the prop to move to the feathered orientation.
Once feathered, no shaft rotation = happy days
The following information is from the Autostream web site
Feathering the propeller:
To feather the propeller, drive ahead at a speed slightly greater than the speed the boat is currently sailing at, this will ensure the propeller is in the ahead position so it will feather correctly .
Switch off the engine whilst still engaged in forward gear .
After the engine has stopped, momentarily engage reverse gear - this will prevent the propeller shaft rotating and the propeller will feather .
To check if the propeller is feathered, put the gear lever in neutral, the propeller shaft should not rotate .
If it does then the propeller is not feathered and the procedure should be repeated .
Once feathered the gear lever can be left in any position and the propeller will not come out of the feathered position until the propeller shaft is rotated by the engine .
This procedure is affective for both hydraulic and mechanical transmissions.

[pbmaise]

Depends if you are a cruiser or racer. I'm a cruiser and I replaced my folding prop with a very big fixed prop.

I found fuel economy to be far better because with same engine Rev the vessel went so much faster.

Secondly that noise when sailing helped me know the speed without getting out of my bunk. I knew within a quarter knot vessel speed just by the sound.

Finally, on one trip I hit something big and bent a blade big time. I simply had to take off the propeller and take it to the machine shop and they hammered it back into shape. They informed me my prop was quality metal since other propellers have cracked.

I doubt a folding stainless steel prop would have survived the initial impact nor have easily been hammered back into shape.

[Stu Jackson]

Originally Posted by breezydays

Like most things it does depend on what kind of sailing you’re planning.>>>>>>>>>>>Make a big difference over distance .

Ann's right, too.

It depends on where you are sailing. I have been dragging a bucket (3 blade fixed, 15x10) for 21 years. I have raced, successfully, against folks with folding props. I have sailed a LOT. SF Bay and ocean and The Delta for 18 years, before I moved north to BC.

I have also motored from SF to BC, around 1500 nm.

My choice was that I didn't want any more moving parts that I could physically personally work on.

Your boat, your choice.

There are advantages and disadvantages between fixed and something else, as well as between those something elses. Important choices you have to make once you do.

I now sail in a place that doesn't have the predictable winds that SF used to have for me. I am sure someone could make the point that when I do get to sail I'd go faster and further with something other than my 3 blade bucket.


But I motor a LOT more here than I ever did in SF.


I still have no moving parts that require maintenance.

Good luck in making your choice.