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Hello all,
Another project this winter is a possible propeller change. I currently have a fixed pitch 20X13 prop and a shaft-lok. I installed the shaft lok maybe 8 months ago as an alternative to a folding/feathering prop, but I keep having this suspicion that I now go slower through the water than when I allow the prop to spin. Unfortunately, I can’t tolerate the racket from the spinning (and I don’t want to generate electricity like that). So after spending about eight bills on the shaft-lok (which works fine, by the way), I’m considering a folding/feathering prop.
Anyway, after reviewing some previous threads from our site, it seems some folks are using an 18″ prop vice 20″ (like mine). I’ve suspected I’m not getting the speed I ought to under power with my current set-up, and am hoping to improve that as well. Maybe a different diameter and pitch?
But back to the subject: I’m impressed with the flex-o-fold prop (three blade) and am leaning that direction. A buddy has one on his Beneteau (speaks highly of his performance under power…about the same as with his old fixed pitch), and I’ve read some of the literature available on the interweb. My buddy reports an increase in sailing speed of about .2 Knots, though this is admittedly somewhat subjective. Other reports of sailing gains on the interweb are all over the map, of course. So I’m wondering about any direct experiences with our boats with this prop or any other option with which folks have had experience. And which size/pitch was selected. Thanks in advance for any thoughts on the subject…
David
Blue Moon, #189 -
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On Fri, Aug 14, 2015 at 7:33 AM -0700, “typhoontye via maillist” wrote:
Hello all,
Another project this winter is a possible propeller change. I currently have a fixed pitch 20X13 prop and a shaft-lok. I installed the shaft lok maybe 8 months ago as an alternative to a folding/feathering prop, but I keep having this suspicion that I now go slower through the water than when I allow the prop to spin. Unfortunately, I can’t tolerate the racket from the spinning (and I don’t want to generate electricity like that). So after spending about eight bills on the shaft-lok (which works fine, by the way), I’m considering a folding/feathering prop.
Anyway, after reviewing some previous threads from our site, it seems some folks are using an 18″ prop vice 20″ (like mine). I’ve suspected I’m not getting the speed I ought to under power with my current set-up, and am hoping to improve that as well. Maybe a different diameter and pitch?
But back to the subject: I’m impressed with the flex-o-fold prop (three blade) and am leaning that direction. A buddy has one on his Beneteau (speaks highly of his performance under power…about the same as with his old fixed pitch), and I’ve read some of the literature available on the interweb. My buddy reports an increase in sailing speed of about .2 Knots, though this is admittedly somewhat subjective. Other reports of sailing gains on the interweb are all over the map, of course. So I’m wondering about any direct experiences with our boats with this prop or any other option with which folks have had experience. And which size/pitch was selected. Thanks in advance for any thoughts on the subject…
David
Blue Moon, #189_______________________________________________
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David,
I have what you have now, except when I re-powered (with a Yanmar 4JHE 54
HP) I fussed around with the pitch (twice) and wound up with 11″ (20LH11)
fixed. I’m very happy with that on this boat with this engine, but have no
idea how that translates to a folding prop (which I think about doing from
time to time). I had a MaxProp many years ago on my previous cruiser and
loved it, but was religious about the maintenance, which helps keep the love
alive. There are lots more choices today. I’ll be curious to see what you
learn here.Tor
Silverheels, P-424 #17
http://www.silverheels.us
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I have a Slipstream 3-blade folding prop. It works very well in forward, at least as well as a fixed-blade prop. It works OK in reverse. I need to run the engine fast to keep the prop open. I can run whirlpools down both sides of the boat in reverse. The prop is geared, so the blades open and close together. I highly recommend this feature. The slipstream is stainless. I like the strength of the stainless prop. I paint it with outdrive paint each spring.
Your estimate of .2 kts improvement under sail is low. It’s more like 1/2 kt or perhaps even more in light air. The boat will also point a bit higher. In heavy air ( greater than 15 kts true) you probably won’t notice a difference.
Your existing prop-shaft may not work with either a folding or feathering prop. Consult the manufacturers website for dimensions regarding the threads, taper and dimensions. I replaced my prop shaft at the same time I replaced the prop, along with everything else in the drive train. Still, I had to cut the threaded end shorter so that the prop nut would attach.
Consult the prop manufacturer for pitch and size recommendations.
See http://www.richardcarter.net/repower/Propeller.html
Rich – BlackSheep #47
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In my humble opinion, if you’re planning long range cruising in places
where parts may be hard to get or very expensive, stay with a fixed prop
and brake if you want. You can quiet the noise of a spinning prop by using
gear oil in the v-drive.Half a knot will seem silly when you’re stuck somewhere with a broken
prop. The key is keep it simple. Fixed props need no maintenance other
than the occasional cleaning and painting. If you have a prop with
multiple moving pieces it can fail in any number of ways, none of them
pleasant or cheap. You could even carry a spare prop for about $450.If you remain in a coastal U.S. cruising mode, the folding, flipping,
whatever props are fine because there’s always TOW Boat U.S.Bob
On Fri, Aug 14, 2015 at 12:08 PM, re.carter— via maillist <
> wrote:Quote:I have a Slipstream 3-blade folding prop. It works very well in forward,
at least as well as a fixed-blade prop. It works OK in reverse. I need to
run the engine fast to keep the prop open. I can run whirlpools down both
sides of the boat in reverse. The prop is geared, so the blades open and
close together. I highly recommend this feature. The slipstream is
stainless. I like the strength of the stainless prop. I paint it with
outdrive paint each spring.Your estimate of .2 kts improvement under sail is low. It’s more like 1/2
kt or perhaps even more in light air. The boat will also point a bit
higher. In heavy air ( greater than 15 kts true) you probably won’t notice
a difference.Your existing prop-shaft may not work with either a folding or feathering
prop. Consult the manufacturers website for dimensions regarding the
threads, taper and dimensions. I replaced my prop shaft at the same time I
replaced the prop, along with everything else in the drive train. Still, I
had to cut the threaded end shorter so that the prop nut would attach.Consult the prop manufacturer for pitch and size recommendations.
See http://www.richardcarter.net/repower/Propeller.html
Rich – BlackSheep #47
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David,
I replaced the 20″ fixed prop with a 20″ Maxprop in the first year of my
ownership, so I can’t make any substantive comparisons with regard to speed
under sail.
As advertised, the Maxprop is more effective under power in reverse than
the fixed prop. I haven’t noticed any difference when motoring in forward
gear.
Since I repowered and replaced the Paragon transmission with a Velvet Drive
I have some difficulty getting the blades to feather when under sail. With
the old Paragon, if the prop did not feather immediately after shutting
down the engine, I just put the transmission briefly in gear and the prop
would feather. With the Velvet Drive that has no effect. I have to get
the boat sailing at about 5 kts before the blades will feather. So much
for the light air performance improvement promised.
I haven’t made any long passages since the repower, so the shaft rotation
under sail is annoying. but not something I feel compelled to eliminate
with a shaft lock or other method.Regards,
John Stevenson
http://www.svsarah.com
Sarah’s BlogOn Fri, Aug 14, 2015 at 12:08 PM, re.carter— via maillist <
> wrote:Quote:I have a Slipstream 3-blade folding prop. It works very well in forward,
at least as well as a fixed-blade prop. It works OK in reverse. I need to
run the engine fast to keep the prop open. I can run whirlpools down both
sides of the boat in reverse. The prop is geared, so the blades open and
close together. I highly recommend this feature. The slipstream is
stainless. I like the strength of the stainless prop. I paint it with
outdrive paint each spring.Your estimate of .2 kts improvement under sail is low. It’s more like 1/2
kt or perhaps even more in light air. The boat will also point a bit
higher. In heavy air ( greater than 15 kts true) you probably won’t notice
a difference.Your existing prop-shaft may not work with either a folding or feathering
prop. Consult the manufacturers website for dimensions regarding the
threads, taper and dimensions. I replaced my prop shaft at the same time I
replaced the prop, along with everything else in the drive train. Still, I
had to cut the threaded end shorter so that the prop nut would attach.Consult the prop manufacturer for pitch and size recommendations.
See http://www.richardcarter.net/repower/Propeller.html
Rich – BlackSheep #47
Original Message
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Hi Tor
Is that a two or three bladed prop?SkipÂ
David,
I have what you have now, except when I re-powered (with a Yanmar 4JHE 54
HP) I fussed around with the pitch (twice) and wound up with 11″ (20LH11)
fixed. I’m very happy with that on this boat with this engine, but have no
idea how that translates to a folding prop (which I think about doing from
time to time). I had a MaxProp many years ago on my previous cruiser and
loved it, but was religious about the maintenance, which helps keep the love
alive. There are lots more choices today. I’ll be curious to see what you
learn here.Tor
Silverheels, P-424 #17
http://www.silverheels.us
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On Whiffler, I re-powered last year with a beta marine 60. I have a 20 inch maxi-prop. After the re-power I had to change the pitch from 16 in to 22 to keep the motor at the proper full throttle RPM.
Steve
Sent from my Verizon Wireless 4G LTE smartphone
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Hey Skip,
Silverheels has what I believe is the original 3-blade bronze propeller AND bronze prop shaft. The shaft checked out on a lathe a few years ago, still true and in good condition. All I changed when I re-powered was the pitch.
Tor
Silverheels, P-424 #17
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My boat came with a 19″ Autostream 3 blade with a factory set 10″ pitch blade. The PO and they(Martec/Autostream) came to agree with the 10″ pitch. After looking extensively here on the forum I concluded that I must have the lowest pitch number than any other 424. My boat moved just fine through the water at all speeds and I had no complaints … until … Just as I was leaving Portsmouth, Dominica couple of months ago heading south I was comfortably motor sailing down the lee side of the island and just as we broke out into the channel and I was considering shutting down the engine I notice the boat performing very sluggish, like I was dragging a net or something. I kept it running and continued motor sailing as the winds between the islands increased to 25 plus and the seas became very sloppy, that’s when it happened BANG! Port aft lower chain plate parted at the deck. Quick tack round to starboard and hove to. After securing the shroud to the forward end of the track and bringing all my spare halyard around to help hold the mast up I put the boat in gear and had NOTHING. the prop was spinning but no fwd thrust. Had to sail and I’d be damned if I’d go back to Dominica to get work done. Onward south sailing with a bed-sheet worth of main and beach towel worth of head sail we made it into St Pierre and anchored under sail. A quick dive overboard just at dusk showed me nothing, all three blades sitting there like not a thing wrong. I n the morning I found the problem and it’s something that will stay with me forever and make me ALWAYS have a spare fixed prop for the boat. The pitch adjusting screw had backed out almost to the point of falling out. The reverse screw was fine I had full reverse. I managed to get a few turns on the screw back in but nowhere where it was. I locked the nut and got on board and put it in gear … I had forward thrust, enough to at least get the anchor up so decided onward south to Rodney Bay where I can get work done and have a diver possibly replace the prop. While bed sheet sailing a second day and approaching Rodney Bay it felt as though still no forward thrust until I finally dropped all sail and I had about 1 knot speed to get to the anchorage. With time, I managed to slowly work the screw back in approximately where it was but I’ll never really know for sure until I do the whole process of readjusting the pitch in calm flat conditions Although it might be fine as it is because as we approached St Georges anchorage in Grenada we had a nice windless calm and I got her to 7.5 knots. I’m never going to fully trust this again and I’ll probably make a habit of diving on it before passages and check to make sure the locking nut is tight. Just thought I’d share, something I haven’t heard as a drawback to feathering props.
Ken
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A well designed folding prop will give the same performance as a good fixed prop of the same size. The prop hub is a bit larger than the fixed prop, but little thrust is obtained from the center of the prop. Blade size, pitch and shape are what matter.
In reverse, a folding prop uses centrifugal force to hold the blades open. You need to give the engine some RPM to keep them fully open. I don’t think I can compare the efficiency of folding vs fixed in reverse.
Rich
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John
I have the habit of putting the engine in reverse before shutting her down. At idle speed, the blades will fold.Rich
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Rich,
What transmission do you have? That hasn’t worked for me with the VD. It
did work with the Paragon (non-hydraulic).Regards,
John Stevenson
http://www.svsarah.com
Sarah’s BlogOn Sat, Aug 15, 2015 at 12:26 PM, re.carter— via maillist <
> wrote:Quote:John
I have the habit of putting the engine in reverse before shutting her
down. At idle speed, the blades will fold.Rich
Original Message
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Hey Skip,
Silverheels has what I believe is the original 3-blade bronze propeller AND bronze prop shaft. The shaft checked out on a lathe a few years ago, still true and in good condition. All I changed when I re-powered was the pitch.
Tor
Silverheels, P-424 #17
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Eclipse came with a fixed 3 blade (18×10) bronze prop
I replaced it with an Autostream feathering prop. Originally it was 18×9
but I adjusted it to be closer to 18×11.
As mentioned by Rich, I did need to make shaft modifications.
We’ve had good experience with it. We haul out and I inspect/grease it
yearly. Will look very closely at lock nuts in the future.Rick
On Fri, Aug 14, 2015 at 10:33 AM, typhoontye via maillist <
> wrote:Hello all,
Another project this winter is a possible propeller change. I currently
have a fixed pitch 20X13 prop and a shaft-lok. I installed the shaft lok
maybe 8 months ago as an alternative to a folding/feathering prop, but I
keep having this suspicion that I now go slower through the water than when
I allow the prop to spin. Unfortunately, I can’t tolerate the racket from
the spinning (and I don’t want to generate electricity like that). So
after spending about eight bills on the shaft-lok (which works fine, by the
way), I’m considering a folding/feathering prop.Anyway, after reviewing some previous threads from our site, it seems some
folks are using an 18″ prop vice 20″ (like mine). I’ve suspected I’m not
getting the speed I ought to under power with my current set-up, and am
hoping to improve that as well. Maybe a different diameter and pitch?But back to the subject: I’m impressed with the flex-o-fold prop (three
blade) and am leaning that direction. A buddy has one on his Beneteau
(speaks highly of his performance under power…about the same as with his
old fixed pitch), and I’ve read some of the literature available on the
interweb. My buddy reports an increase in sailing speed of about .2 Knots,
though this is admittedly somewhat subjective. Other reports of sailing
gains on the interweb are all over the map, of course. So I’m wondering
about any direct experiences with our boats with this prop or any other
option with which folks have had experience. And which size/pitch was
selected. Thanks in advance for any thoughts on the subject…David
Blue Moon, #189_______________________________________________
maillist mailing listhttps://pearson424.org/mailman/listinfo/maillist_pearson424.org
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Rick, nice to know someone else has a similar prop. My PO played with
modifying the original bronze prop and then bought the Autostream. I think
he was never happy with the changes he made. I still have the bronze prop
and when I had my new stainless steel shaft made recently, I made sure it
would accommodate the old bronze prop if needed. As a matter of fact the
owner of the machine shop (Jack) let “me” actually cut the final end at the
lathe, so I would be sure I could refit the old bronze if needed. My next
haul out I’ll be making sure there is fresh Lock-tite on my adjustment
screws.Ken
On Mon, Aug 17, 2015 at 12:45 PM, Rick Dugger via maillist <
> wrote:Eclipse came with a fixed 3 blade (18×10) bronze prop
I replaced it with an Autostream feathering prop. Originally it was 18×9
but I adjusted it to be closer to 18×11.
As mentioned by Rich, I did need to make shaft modifications.
We’ve had good experience with it. We haul out and I inspect/grease it
yearly. Will look very closely at lock nuts in the future.Rick
On Fri, Aug 14, 2015 at 10:33 AM, typhoontye via maillist <
> wrote:Hello all,
Another project this winter is a possible propeller change. I currently
have a fixed pitch 20X13 prop and a shaft-lok. I installed the shaft lok
maybe 8 months ago as an alternative to a folding/feathering prop, but I
keep having this suspicion that I now go slower through the water thanwhen
I allow the prop to spin. Unfortunately, I can’t tolerate the racket
from
the spinning (and I don’t want to generate electricity like that). So
after spending about eight bills on the shaft-lok (which works fine, bythe
way), I’m considering a folding/feathering prop.
Anyway, after reviewing some previous threads from our site, it seems
some
folks are using an 18″ prop vice 20″ (like mine). I’ve suspected I’m not
getting the speed I ought to under power with my current set-up, and am
hoping to improve that as well. Maybe a different diameter and pitch?But back to the subject: I’m impressed with the flex-o-fold prop (three
blade) and am leaning that direction. A buddy has one on his Beneteau
(speaks highly of his performance under power…about the same as withhis
old fixed pitch), and I’ve read some of the literature available on the
interweb. My buddy reports an increase in sailing speed of about .2Knots,
though this is admittedly somewhat subjective. Other reports of sailing
gains on the interweb are all over the map, of course. So I’m wondering
about any direct experiences with our boats with this prop or any other
option with which folks have had experience. And which size/pitch was
selected. Thanks in advance for any thoughts on the subject…David
Blue Moon, #189_______________________________________________
maillist mailing listhttps://pearson424.org/mailman/listinfo/maillist_pearson424.org
_______________________________________________
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Thanks to all for your replies! Interesting discussion. Very interesting story from Ken regarding simultaneous rig and prop malfunction. Glad it wasn’t me! Carrying the old prop as a spare seems a most prudent thing to do. Hopefully I won’t have to modify my shaft so that I can retrofit the fixed pitch prop if needed.
After reviewing as much info as I could find on the internet, and speaking with two friends who have the flex-o-fold on their boats, I will probably go the flex-o-fold route. The biggest drawbacks of the folding props appears to be backing thrust, particularly at low RPM, and for those of us with hydraulic transmissions, the props won’t fold unless the shaft can be stopped momentarily. Given the advantages of the folding prop over the feathering variety, which include more efficient/faster motoring, simpler operation, less maintenance, and cheaper cost, I think I can learn to live with the drawbacks.
Speaking of the backing thrust challenges associated with folding props, after talking with my two friends with the flex-o-folds and bringing this up, they both said that they had not noticed this…that their boats seemed to stop as well as they did before they retrofitted. However, it is interesting to note the Flex-o-fold says to use more RPM when reversing to stop the boat.
I depended pretty heavily on an article in Yachting Monthly (British mag) which did a pretty thorough review of folding and feathering props some years ago. The Flex-o-fold came away with very good ratings. Best forward thrust, minimal prop walk, and highest reverse thrust (I know, doesn’t make sense…I’m assuming the test was at high RPM).
Thanks again for your comments, and I will post results of whatever route I take…probably won’t be will Spring.
David
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Hi David,
I have a friend with an Autostream prop who loves it and I read great things about it from other owners and tests but when I checked they didn’t make one to fit my original 1.5″ bronze shaft.  I didn’t want to modify the shaft because I want to keep the old fixed prop for a backup.
So I am also looking at the Flex-o-Fold who does make one to fit without modifications. I know several cruisers with Flex-o-Folds and none of them have any complaints, including power in reverse.  However I don’t think they have hydraulic transmissions so don’t have the issue of folding.
The only complaint I have.  When I originally contacted them to ask if they had a model to fit my shaft they didn’t respond to emails.  Phone call got immediate response.  I’ve heard the same in the past from others but no serious complaints about customer service and support when you need it.
Skip
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