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 Izablue2 |
transmission |
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Posts: 120 04/23/08 10:09:42 |
I just got a e-mail from H&S yachts(where we bought the boat) that Yanmar recommends that when the boat is sailed, the tramsission is to remain in neutral.
Yanmar states that their warranty will be void if don otherwise.
I always ran mine in reverse! Any thoughts out there? Mark Izablue 835/3 |
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sashay567 |
#1 | |||
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Posts: 188 04/23/08 14:01:28 |
Yep, that is what Yanmar recommends. The reason they use is that it may jam the clutch cone. FWIW, because I have an autoprop, I have to put mine into forward
to get the prop to feather (long technical explanation why). Dave Swain over at Yanmarhelp.com says that while Yanmar's recommendation really applies to
fixed props, there is little chance of damage if you have a feathering or folding prop.
I think there has been discussion in the past where people sailing with the transmission in reverse have had great difficulty shifting to neutral from reverse while sailing. People have reported that they must almost stop the boat to get the transmission out of reverse. Forcing it can't be good. Some people also reported that they just start the engine in gear and then shifting is easy.
Rodney Kidd, C-42 #567 Sashay, 2 Cabin Fin, Marina Village, Alameda, CA
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tomcharron2 |
Transmission always in Reverse while Sailing | #2 | ||
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Posts: 42 04/23/08 20:48:39 |
This has worked for all the 9+yrs I had the Catalina 3 Bladed Stock prop in place.
Stops auto prop rotation (quite noisy when sailing in neutral). Never had problems with tranmission following this procedure. Procedure was/is: 1.) Set sails 2.) Kill engine (if not already done before setting sails) 3.) Put Transmission in REVERSE to stop auto rotation 4.) Always Start engine if needed for power WHILE TRANSMISSION IS STILL IN REVERSE!! Do Not try to Shift OUT of REVERSE while sailing. 5.) Shift to forward only after engine is restarted and running and still in reverse. BTW it is almost impossible to shift from Reverse to Neutral or Forward while sailing with Transmission in Reverse and engine off!!! Hope this helps... Tom Charron |
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seaair |
Why reverse? | #3 | ||
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Posts: 60 04/24/08 07:51:23 |
Why put the transmission in reverse? Why not forward?
Unless I am totally turned around (which is quite possible), putting the transmission in reverse will try to turn the engine backwards, which could lead to all sorts of problems. If it is in forward, it will try to turn it in the usual direction, and it would be easier on the system to start while under sail. In either case, there is not enough force on the prop to actually turn the engine. I am confused.
Warren
Seattle, WA Sutlej, #920 3-cabin pullman
Last Edited By: seaair 04/24/08 14:55:09.
Edited 1 time.
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tomca |
#4 | |||
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Posts: 76 04/24/08 08:39:59 |
With my Flex O Fold propeller I always sail with the transmission in reverse to get the prop to fold properly. I have been doing this for 4 yrs now without a
problem. On my previous boat, a Catalina 38, I also sailed with the transmission in reverse to stop the shaft from spinning and allow the propeller to fold
correctly. I feel the wear on the transmission from constent spinning is worse then having the gears lock in place and hold the shaft. Now I understand that
with a folding propeller there is considerably less force on the transmission then with a fixed prop, but the constent turning with the fixed propeller I think
will lead to more wear.
Tom
Maxwell #766 2-cabin Pullman Dana Point, CA |
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Sandy Golden |
To put in reverse or not to put in reverse | #5 | ||
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Posts: 13 04/24/08 11:49:13 |
I called my Yanmar mechanic Pacwest in San Diego. They are very experienced Yanmar shop. Was told that Yanmar has put out a service
advisory that when sailing and engine is shutdown, it must be left in neutral or the warranty on the transmission will be voided if a problem develops. Was
told this advice probably was to protect Yanmar from liability if your prop hits something while in reverse when engine is off and there may have been one
problem recently. Was also told that they (Pacwest) never have seen a problem because engine was placed in reverse. I have requested a copy of the service
bulletin and will post it when I get it.
Sweet Angel #974 |
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nickwigen |
Why Reverse | #6 | ||
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Posts: 210 04/24/08 18:38:45 |
In forward the prop will continue to turn with the transmission pressure plates dragging. The mechanical configuration is such that as the torque increases
the plate pressure increases. In reverse the torque is in the correct direction to increase the pressure. In forward they will drag. The torque delivered by
the stalled prop is not enough to turn the engine. Until we installed a feathering prop we used the method Tom Charron describes.
Nick Wigen
Ursa Minor #178 FK, 3-Cabin Portland, Oregon |
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tomcharron2 |
Prop Rotates when sailing in forward or neutral on C42 #631 | #7 | ||
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Posts: 42 04/25/08 09:00:25 |
In answer to "why not place transmission in Forward while sailing?"...
The Prop shaft (with engine off) while sailing (either in NEUTRAL or FORWARD) ROTATES CONTINUALLY...at least on my C42 MiVida #631. This rotation is fairly noisy too....not so nice when sailing expecially when down below. And contributes to continual wear on transmission etc. When the transmission is placed in REVERSE while sailing all prop/shaft rotation stops as the prop is pulled thru the water. See previous post for details regarding mechanics involved... Hope this helps Tom Charron
Last Edited By: tomcharron2 04/25/08 09:16:10.
Edited 1 time.
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pwinterfeld |
Rotation | #8 | ||
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Posts: 103 04/26/08 05:38:38 |
I have been sailing for years with the transmission in neutral (on several different boats including 2 Catalinas) The discussion on whether to leave the
transmission in neutral or reverse has gone on for so many years. There are good reasons for each setting but the vibration more than the noise has always
bothered me - has anyone installed a brake for the shaft ??? I have seen the advertisement for such a device in many magazines. Yes, I know its another thing
to remember when starting the engine and thats why I have not considered installing one of those brakes. I would like to hear from someone who has actually
used one of these brakes and has it installed on their CA 42.
Peter C'est la Vie Hull #746 |
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yorkrose |
#9 | |||
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Posts: 250 04/28/08 16:50:30 |
I would not worry at all about extra wear on the transmission due to shaft rotation while sailing. There are virtually no forces involved, other than a bit on
the thrust bearing. The transmission parts run on roller bearings and are well oiled. They should last for many years under a condition of free-wheeling.
I agree with the noise comments. In my view that is the only thing to be considered. We initially placed the transmission in reverse, like the conventional recommendation, but had the standard Yanmar problem of not being able to go back to neutral to start. Fortunately the boat doesn't have a start interlock switch, so we simply started in gear. We switched to letting the prop free-wheel a couple of years ago. In moderate conditions the sailing speed improved by a half a knot or so. There is a little bit of extra noise, but it is not a problem. By the way, I just saw a letter in Sail Magazine from a fellow who claims that a rotating prop creates more drag than a stationary prop. This is an old tale that takes root from the aviation field. There is little double that a rotating prop on a dead engine in an airplane creates a lot more drag than a stationary feathered prop. The disadvantage of a rotating prop over a stationary, but not feathered, prop is not as great, but it probably still exists for an airplane. What many people forget, including the letter writer, is that a rotating prop on an airplane has to turn the entire engine. That takes energy, and therefore creates a lot of drag. On the other hand, spinning a couple of shafts in a boat transmission (in neutral) takes almost no energy. The only energy of concern is what is imparted to the water in the form of turbulence. I have not done any scientific experiments, but it does not appear that a spinning boat prop creates any more turbulence than a locked prop, probably less. The analogy to airplanes is pretty strained due to the different viscosity of the fluids and the large difference in prop blade shapes. Regards, Gene Fuller Yorkshire Rose, C42 #870 |
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nickwigen |
Free Wheeling | #10 | ||
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Posts: 210 04/29/08 06:02:50 |
Gene: I think we saw the same letter about airplanes and I totally agree with your observation about drag, old wives tales, etc. My experience with
free-wheeling vs. locking is the same as yours with a bit of speed increase when we let it spin. We resolved the issue about 4 yrs ago with a feathering prop.
I think the locked prop causes a lot more turbulence. The biggest thing I noticed with our 1990 boat (stubby barn door rudder) was how much more effective the rudder was with the prop free wheeling when hard to weather. I tested it out several times and the loss of rudder efficiency was very noticable when we locked up the prop.
Nick Wigen
Ursa Minor #178 FK, 3-Cabin Portland, Oregon |
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