Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 13-10-2018, 19:00   #1
Registered User

Join Date: Sep 2018
Posts: 2
Folding Propeller that folds in reverse

Hi gang.
Just cleaned up 2x folding propellers and coated with propspeed.
Back in the water and now OK in forward but initially open in reverse then fold as revs increase. SD20 saildrive with dog clutch that is engaging.
?? why previously working propeller now not working.
Could we have lightened the blades in our cleanup ??

More to the point how do we fix the problem
Docaroo; current sanity rating withheld
__________________

Docaroo is offline   Reply With Quote
Old 13-10-2018, 23:56   #2
Moderator
 
JPA Cate's Avatar

Join Date: Nov 2011
Location: aboard, cruising in Australia
Boat: Sayer 46' Solent rig sloop
Posts: 13,690
Re: Folding Propeller that folds in reverse

Hi, Docaroo,

Welcome aboard CF. We have one only (monohull) Flex-O-Fold 3 blade prop, and it only closes when the water pressure doesn't hold it open. Maybe what happened with yours is that you went slow enough in reverse that the water pressure from the boat's movement astern caused them to close? This may be crazy as anything, just a thought.

Ann
__________________

__________________
Who scorns the calm has forgotten the storm.
JPA Cate is online now   Reply With Quote
Old Yesterday, 00:13   #3
Registered User
 
Dsanduril's Avatar

Join Date: Aug 2011
Location: Over the Top, Toward Africa
Boat: Outremer 50S
Posts: 1,704
Re: Folding Propeller that folds in reverse

Just a shot in the dark, do the engines (propellers) rotate the same direction? I think with a saildrive it is pretty rare to get a counter-rotating twin, but... Any chance you swapped the props?
Dsanduril is offline   Reply With Quote
Old Yesterday, 01:07   #4
rom
Registered User

Join Date: Mar 2016
Boat: Lagoon 440
Posts: 552
Re: Folding Propeller that folds in reverse

Quote:
Originally Posted by Dsanduril View Post
Just a shot in the dark, do the engines (propellers) rotate the same direction? I think with a saildrive it is pretty rare to get a counter-rotating twin, but... Any chance you swapped the props?

Wouldn't that just perfectly invert forward & reverse gears ? Docaroo says the boat is still fine forward. It is the centrifugal force that keeps the blades open in reverse. I also have two of those nice 3 blades FoF, woring perfectly forward & reverse.
rom is offline   Reply With Quote
Old Yesterday, 01:59   #5
Registered User

Join Date: Sep 2018
Posts: 2
Re: Folding Propeller that folds in reverse

Thanks gang
Thanks for your thoughts
We are currently in a marina berth and a little reticent to leave it !!
So the props are closing themselves even when we are stationary.
ie tied up and trying reverse (as well as when mobile; docking was a little entertaining as we discovered the problem).
The props both rotate the same way.
FOF 2 blade props really only mount one way so stuffing that up shouldn'd be the problem (although not discounting it)
So still trying to work out possible causes prior to hauling our little beastie out and fixing it.
All ideas welcome !!
Regards
Docaroo is offline   Reply With Quote
Old Yesterday, 02:24   #6
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 10,384
Images: 14
Re: Folding Propeller that folds in reverse

Have you seen this:

Pete7 is offline   Reply With Quote
Old Yesterday, 09:07   #7
Senior Cruiser
 
SV Bacchus's Avatar

Cruisers Forum Supporter

Join Date: Apr 2016
Location: Stuart, FL
Boat: Leopard 42 OV
Posts: 1,138
Re: Folding Propeller that folds in reverse

I have MaxProps so I have no experience with the folding props. So many on this thread swear by the FlexFolds that I can't help but think it has to be some type of installation error.

If the prop was disassembled to paint, could it have been reassembled wrong? In other words, assembly is wrong but actual mounting on the boat is correct leading to the confusion as to why it doesn't engage?
__________________
SV Bacchus - spreading libations world wide, via sailboat, to help the "up tight" relax and enjoy life!
SV Bacchus is offline   Reply With Quote
Old Yesterday, 09:37   #8
Marine Service Provider

Join Date: Sep 2011
Location: California
Boat: Alerion Express 38 Yawl
Posts: 350
Re: Folding Propeller that folds in reverse

Sorry that I can't be more helpful in diagnosing this, but I do have to compliment you on your videography. Many diagnostic videos make things more confusing rather than less, and your video is really clear.

Second, can you take any solace in the fact that at least your propeller has low drag when operating in reverse? Perhaps not...

Chuck
Chuck Hawley is offline   Reply With Quote
Old Yesterday, 09:58   #9
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 10,384
Images: 14
Re: Folding Propeller that folds in reverse

Chuck, sadly not my video, wish it was. I found it a while back whilst thinking about a FOF prop, project now on hold for while.

Pete
Pete7 is offline   Reply With Quote
Old Yesterday, 17:07   #10
Registered User
 
tpkas's Avatar

Join Date: Aug 2010
Location: Lake Macquarie NSW Australia
Boat: FP Mahe 36
Posts: 49
Re: Folding Propeller that folds in reverse

When the prop spins in reverse it generates a force that not only gives power to reverse the boat but will also close the blades. This blade closure is counteracted by the centrifugal force wanting the blades to open. My understanding is that as a result of the balancing of these forces all folding props will fold to some extent when in reverse and why the power available in reverse is not as great as that when the blades are fully open in forward gear. By cleaning the props you may have increased the efficiency of the blade which, when in reverse, will increase its propensity to close. I have just fitted folding props to our boat and there is a reduction in available reverse power which you have to get used to.
tpkas is offline   Reply With Quote
Old Yesterday, 19:11   #11
Senior Cruiser
 
senormechanico's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 6,274
Re: Folding Propeller that folds in reverse

Apply more power in reverse.
__________________
Ban pre-shredded Cheese. Make America Grate Again.
senormechanico is offline   Reply With Quote
Old Yesterday, 21:43   #12
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 13,053
Re: Folding Propeller that folds in reverse

Quote:
Originally Posted by senormechanico View Post
Apply more power in reverse.
This ^^^^^.

The higher the revs, the more centrifugal force opening the blades. Our FOF three blade does pretty well in reverse, better than other folders we've had, but still not like a good feathering prop. Some tests have shown better bollard pull in R than a standard fixed prop.

Jim
__________________
Jim and Ann s/v Insatiable II on the Clarence river once again, awaiting the next N'ly.
Jim Cate is online now   Reply With Quote
Old Today, 02:36   #13
Sponsoring Vendor
 
EWOL Props's Avatar

Community Sponsor

Join Date: Nov 2015
Posts: 90
Re: Folding Propeller that folds in reverse

Folding props have this issue in reverse, they push water forward, so as a reaction the blades tend to close, that is why boats with folding props are more difficult in reverse maneuverability
Now why this was not happening before cleaning them ? I am scratching my head on this...
I believe that probably before cleaning the blades were a bit more stiff than now due to fouling or incrustations, now that they are cleaned and have less friction on movements, hence water pressure now wins against friction of blades pushing them to close.
EWOL Props is offline   Reply With Quote
Old Today, 04:16   #14
rom
Registered User

Join Date: Mar 2016
Boat: Lagoon 440
Posts: 552
Re: Folding Propeller that folds in reverse

Quote:
Originally Posted by senormechanico View Post
Apply more power in reverse.

Hopefully there is something wrong elsewhere because I would be very unhappy if that is the normal behaviour of 2 blades FoF. My 3 blades FoF pull me real good in reverse at idle, 800 RPM Yanmar 4JH4.


I have no idea why it used to work and does not work anymore. Docaroo, did you try to contact FoF directly ?
__________________

rom is offline   Reply With Quote
Reply

Tags
propeller, rope

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Folding Prop and SD20 - neutral or reverse? Zoid Engines and Propulsion Systems 14 15-06-2015 02:02
volvo penta 3 blade folding propeller dropping blades fordna Propellers & Drive Systems 1 13-05-2014 03:52
For Sale: Folding Propeller wimpel Classifieds Archive 0 29-12-2013 13:45
Want To Buy: 19" x 11" LH Folding Propeller blewett_john Classifieds Archive 4 09-11-2013 16:54
For Sale: Martec MK III Eliptec Folding Propeller bofus11 Classifieds Archive 0 13-02-2011 16:35



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 23:03.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.