Prop shaft turns while sailing?

McIntoshUSA

McIntoshUSA

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Jun 5, 2014
209
Capital Yacths Newport MKIII 30 Punta Gorda, Fl
I recently noticed that while sailing my prop shaft turns. If I put the engine in reverse(engine is off while sailing) then it does not turn. It does not seem to change my speed either way. Seems like if the prop shaft is turning always while sailing that it might wear the bearings eventually.

So my question is: Should I leave the transmission in neutral while sailing (shaft turns) or should I put it in reverse to stop it from spinning?


Thanks Mike
 
quadrille38

quadrille38

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Apr 11, 2010
969
Hunter 38 Whitehall MI
Suggest you do a search on the site. There are probably a dozen previous threads on this subject.

Several reposts of a service bulletin from Yanmar on this subject.
 
Jalepeno

Jalepeno

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Mar 2, 2008
406
Cal 25 mk II T-Bird Marina, West Vancouver
It is not the brand name of the reduction gear / clutch unit the design. Do your research.
 
quadrille38

quadrille38

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Apr 11, 2010
969
Hunter 38 Whitehall MI
McIntoshUSA said:
I recently noticed that while sailing my prop shaft turns. If I put the engine in reverse(engine is off while sailing) then it does not turn. It does not seem to change my speed either way. Seems like if the prop shaft is turning always while sailing that it might wear the bearings eventually. So my question is: Should I leave the transmission in neutral while sailing (shaft turns) or should I put it in reverse to stop it from spinning? Thanks Mike
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Here is the 2008 Yanmar service bulletin. As referenced earlier it has been posted in several other threads on the site.


Scott B said:
Yanmar Advisory Number: MSA08-003: DATE February 8, 2008 Dealers and OEMs TO: All Marine Distributors SUBJECT: Gear in Neutral While Sailing All MODELS: All Sailboat Engines We continue to get questions regarding the correct gear position while sailing with the engine OFF. This advisory is issued as a reminder; 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. This damage will not be covered by Yanmar’s Limited Warranty. Please instruct customers and dealers who deliver the sailboat to the customer, of the correct (Neutral) position for the marine gear while sailing. If the customer desires that the propeller shaft not spin while sailing, either a folding propeller, shaft break, or other suitable device may be used. However, Yanmar accepts no responsibility for the selection, installation, or operation of such devices. Please also refer to Marine service advisory “MSA07-001_Yanmar Sail Drive Propeller Selection” for additional information. If you have any questions regarding this advisory please contact a Customer Support representative.
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Benny17441

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May 24, 2004
7,164
CC 30 South Florida
This horse has been beaten to death. Yanmar has learned that the overall best option is to sail with the transmission in neutral and that is what they recommend. If you want the details check out the hundreds of postings in file.
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,006
Catalina 34 224 Maple Bay, BC, Canada
Benny17441 said:
This horse has been beaten to death. Yanmar has learned that the overall best option is to sail with the transmission in neutral and that is what they recommend. If you want the details check out the hundreds of postings in file.
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Benny's right, but of course there may be "new" skippers here.

Short answer: two types of transmissions---Hurth either reverse or neutral NEVER forward; ones with Yanmar engines (Kazaki (? sp)) neutral.

When in doubt? Search "transmission position" :eek::eek::eek::):):)
 
higgs

higgs

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Aug 24, 2005
3,708
Nassau 34 Olcott, NY
Movement=wear to bearings. I don't care what Yanmar says, mine goes in reverse which enables my Maxi-prop to feather.

A free wheeling prop can foul on a sheet which inadvertently falls overboard.
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,360
Alden 50 Sarasota, Florida
higgs said:
Movement=wear to bearings. I don't care what Yanmar says, mine goes in reverse which enables my Maxi-prop to feather.

A free wheeling prop can foul on a sheet which inadvertently falls overboard.
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From the PYI manual:
The best way to feather the prop is:
Power in FORWARD at 2 to 3 knots, and
Kill the engine while still engaged in FORWARD.

Implied is to shift to neutral to feather.

It goes on to say " don't kill the engine while in reverse. In this case, the blades will be in reverse position preventing the blades from feathering".

Sounds like you are confusing locking the blades in reverse with being feathered.
 
higgs

higgs

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Aug 24, 2005
3,708
Nassau 34 Olcott, NY
Hmm I could swear my manual said reverse, but I can't check now as the manual is aboard the shrink wrapped boat 1300 miles away. Thanks for the comment, Don.
 
quadrille38

quadrille38

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Apr 11, 2010
969
Hunter 38 Whitehall MI
higgs said:
Hmm I could swear my manual said reverse, but I can't check now as the manual is aboard the shrink wrapped boat 1300 miles away. Thanks for the comment, Don.
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My Maxprop manual says similar. Stop engine while in forward, blades will feather and then it says shift to neutral.

I understand your thought on wear but there are contained in the many threads on this subject substantial evidence that if the transmission is properly lubricated there is no excessive wear. So I'm biased to the manufactures position that if you don't follow their recommendation you void the warranty. That's pretty compelling for me. Of course that's for Yanmar with Kanzaki transmission. Our previous boat a Catalina 34 with Hurth transmission stated reverse when sailing.
 
rardiH36

rardiH36

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Jun 21, 2007
2,117
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Over the last several years, I have certainly seen many many many times threads about Yanmar's TSB about putting the tranny in neutral while under sail power. Struck me as "what the heck?" since it is contrary to to the previous long enduring convention of years ago ... Shift into to reverse while under sail.

What I would like to know: Does the current Yanmar advice mainly pertain to more recent vintage engines/transmissions as opposed to the ones installed with the QM's and GM's of 25-30 years ago which many of us still have?

After reading one of these neutral vs. reverse threads, I have always meant to call Yanmar to ask this question. Maybe I'll do it this time.
 
Ralph Johnstone

Ralph Johnstone

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Jan 4, 2006
7,212
Hunter 310 West Vancouver, B.C.
rardiH36 said:
Does the current Yanmar advice mainly pertain to more recent vintage engines/transmissions as opposed to the ones installed with the QM's and GM's of 25-30 years ago which many of us still have?
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It's the Kanzaki transmission that requires being left in neutral.

If your's is a Kanzaki on one of the older QM and GM model engines, I would follow the manufacturer's instructions.
 

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Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
People often overlook that it is not Yanmar that makes the transmissions.
 
rardiH36

rardiH36

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Jun 21, 2007
2,117
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Ralph Johnstone said:
It's the Kanzaki transmission that requires being left in neutral.

If your's is a Kanzaki on one of the older QM and GM model engines, I would follow the manufacturer's instructions.
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Wish it was that easy! But unfortunately Kansaki instructions on this topic for my very old uKBW10 I have not been able to find on line. And comments about doing reverse or not on the various forums has been conflicting. Much like the transmission oil type specified on the name plate ... conflicting as in the attached photos. ATF only is what is on my transmission's nameplate. Or should I disregard and instead accept that it's the owner's choice of either ATF or 20 or 30 weight engine oil as was imprinted on the same model's nameplate but manufactured only a bit older?

My gut feeling: My transmission is really old but like the engine, performs very well. Am I risking more by putting it in reverse while sailing which locks the shaft from turning. Torque imparted from the prop back to the transmission can't be very much. Or letting it spin freely might wear down quicker the already long-in-the-tooth bearing and seal?

I'll try to remember to call Yanmar this week to ask. And hope that the person I talk to has specific information at hand about a 35 year old KBW10. I expect that Yanmar no longer provides much support for this model. Hence the tech might not have any meaningful model references at hand ... and instead will default back to the current directive because its the easiest answer.
 

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Chris Patterson

Chris Patterson

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Oct 17, 2011
2,809
Ericson 29 Southport..
That gearbox says 'ATF type A fluid. Why would you try anything else? ATF nor oils have gone through any drastic changes over the short years, nor is the expense six of one, and a half dozen of the other.

Change the oil, and put in fresh ATF.

Again I will say. Why anyone would chance blowing out a thousand dollar gearbox over five bucks worth of fluid....
 
kloudie1

kloudie1

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Nov 6, 2006
10,066
Hunter 34 Mandeville Louisiana
Yanmar owns Kanzaki.. That transmission needs ATF because it is a multiple disk clutch and not a cone clutch transmission. ATF-A is an old oil that is no longer made. Dexron VI is the correct juice to use in that transmission. Dex III is also suitable but is an older specification oil.
 
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