Neutral of Forward gear while sailing?

galynd · Nov 25, 2009

I put mine into reverse gear. It's also a Yanmar and I've been told it's not good for the transmission if it spins in neutral so I don't take a chance.

Time Out · Nov 25, 2009

Read the manuals for your equipment. It will say specifically what gear your particular transmission should be left is while sailing. This topic has been brought up several times before and I believe for most transmissions its best to leave it in reverse or neutral but not forward as this can cause damage. The best way to be sure for your engine and transmission is to simply read the manuals.

Fairwind · Nov 25, 2009

I tilt my lower unit up out of the water..No spin, no wear, no drag..

Andy1237 · Nov 25, 2009

This subject has been thoroughly covered in this website, although a strict consensus was never agreed upon that I know. The general tendency for most is put the transmission in reverse. That's what is recommended by my Yanmar manual and my folding prop directions, and that's what I do.

Stu Jackson · Nov 25, 2009

Here's why

It is CRITICAL that you include the transmission, not only the engine.

We dont' have a Yanmar, but here's a good example of how you need to figure out the right answer to your question: http://forums.catalina.sailboatowners.com/showthread.php?p=668726&highlight=transmission

It's what the folks have said:

Find out your transmission, then look up YOUR transmission manufacturer's instructions.

Hermit Scott · Nov 25, 2009

What is the damage that is casued by leaving the gear in forward? How does engaging it in reverse prevent it?

Stu Jackson · Nov 25, 2009

Why not

ask the manufacturers? The label says don't. Good question, wrong place to ask??? That said, I'd like to know to document and stick on our website.

Idratherbesailing · Nov 26, 2009

2QM15 with a standard transmission as it come from the factory, the operators manual says put the transmission in gear while sailing...transmission design is such that the gears aren't lubricated if the engine input shaft to the transmission isn't turning (which it won't be if the engine is off). Doesn't specify whether reverse or forward, but most people put it in reverse.

This is not true for all transmissions, for example a Velvet Drive as fitted to a lot of old Perkins diesels, is hydraulic and it turns no matter what is engaged if the engine is off...but it also is designed to do that and it doesn't hurt the transmission at sailing speeds.

Bottom line is read the manual for the transmission/engine combo you have, that's the source. Look online, you can find the manuals.

frank balcer · Nov 26, 2009

My Hurth transmission information booklet says to put this model (HBW50) in Reverse when sailing.....

DougM · Nov 26, 2009

It probably doesn't matter which gear, but it makes sense to keep it in gear. This discussion will probably go on forever on this forum. I have a Yanmar 2GM20 and was instructed to put it into reverse. The only problem I encounter is getting the thing back into neutral to restart the engine. I haven't really figured that one out. I don't know if keeping it in forward would have the same effect.

I have a skeg and can align my 2 blade prop vertically so it doesn't create as much drag. I just have a couple of ink marks on the prop shaft hub to align. I don't bother with it if I'm day sailing though.

kloudie1 · Nov 26, 2009

Yup, the Yanmar (Kanzaki) transmission is OK in reverse to lock it .. The design on the engaging cones (the things that drive the gears) is such that they will slip in contact when in forward gear. The slipping will wear the cones to the point that forward gear will slip when being driven. Neutral is OK since the transmission is unloaded and teh shaft is spinning to lube things if teh oil level is correct... no drive forces other than the miniscule amount that is needed to turn the prop.. No load equals very little wear.. but the sound can be annoying .. Mainsail's test said freewheeling would give a little more speed.. Any hydraulic transmission or hydraulically engaged transmission will need to be put into reverse to lock it. If it is not clear what kind it is, put it in reverse.

Warren Milberg · Nov 26, 2009

In addition to all the good information already provided in the other posts here on this subject, it would appear to me that any arrangement that allows the shaft and prop to spin while sailing is going to allow some amount of unnecessary wear on both the cutless bearing and packing gland. Hard to know if such wear is "significant." What, if any, are the negatives of putting the trans in reverse (unless your engine manual says not to)?

kendall · Nov 26, 2009

Hermit Scott said:
What is the damage that is casued by leaving the gear in forward? How does engaging it in reverse prevent it?

Potential for damage depends on the lubrication system of the trans, if it's splash oiling, no damage is done by letting it turn. If it's pressure oiled then oil won't circulate and you'll get metal to metal contact.

Defaulting to a locked prop is good practice because it eliminates any potential damage for people who don't know what kind of trans they have.

Ken.

jibes138 · Nov 28, 2009

Conjecture?

Does leaving it in forward have the potential to turn over the engine when the forces on the prop are great enough? My Universal M25 says to put it in reverse. I certainly wouldn't want the engine turning over while off.

Stu Jackson · Nov 28, 2009

jibes138 said:
1. Does leaving it in forward have the potential to turn over the engine when the forces on the prop are great enough?

2. My Universal M25 says to put it in reverse. I certainly wouldn't want the engine turning over while off.

jibes,

1. Yes, in a way. The shaft turns the engine does not. Maine Sail has done a analysis on prop drag.

2. That's NOT what it says. What is says is on the red sticker, here: http://www.c34.org/faq-pages/faq-transmission-position-sailing.html

There really is a difference between
a. do not put it in forward
and
b. reverse OR neutral is OK

compared to
c. My Universal M25 says to put it in reverse

Subtle, but maybe just the imperfect English language...

And it's the transmission, as you know, not the engine, that dictates the position.

jibes138 · Nov 28, 2009

Thanks

Stu
Thanks for pointing out the red sticker. i don't have a red sticker on my boat. My operators manual very clearly states to put the transmission in reverse when sailing. I'm not sure I understand your response. You said the shaft turns but the engine does not?? My question was if the engine was in forward gear is it possible for the forces on the propeller to be large enough to turn over the engine, in other words enough torque to exceed the compression in a cylinder? I don't think the shaft can turn while in gear without the engine turning? Are you suggesting that it can? What will allow the shaft and gear train to slip?

Stu Jackson · Nov 28, 2009

If the transmission is in neutral, the shaft will spin. If the transmission is in reverse the shaft doesn't spin. If the transmission is in forward you need a new transmission. The engine won't turn.

When you say "my operators manual" is this an O'Day publication or something that came with the Universal engine manual? I forget whether the Universal manual says anything about the transmission position when sailing, but I can go check.

Here's the Hurth manual: http://www.c34.org/manuals/Hurth_HB_Transmission_Manual.pdf

I checked the Universal engine manual: it says don't put it in the same position as the boat is traveling! Must have translated that from the original Euclidian!!!

jibes138 · Nov 29, 2009

Stu Jackson said:
If the transmission is in neutral, the shaft will spin.

Isn't this true only if the boat has a velocity fast enough for the forces on the propeller to overcome the friction forces in the system of prop shaft and transmission? I often keep my transmission in neutral while docked and the shaft does not spin.

If the transmission is in reverse the shaft doesn't spin. If the transmission is in forward you need a new transmission. The engine won't turn.

My question was can the forces on the propeller be large enough to turn the engine over? Let's say you are out in the gulf stream with a 35 knot wind blowing dead astern and you have some sail up and are surfing down waves at 12 knots. Will the engine be spinning if he tranny is in forward gear due to the forces on the propeller. Kind of like trying to start a manual transmission car by popping the clutch in gear. Why do I need a new transmission? What specific damage will result from sailing in forward gear? I don't do this but just curious, I thinnk Hermitt also asked this question.

When you say "my operators manual" is this an O'Day publication or something that came with the Universal engine manual? I forget whether the Universal manual says anything about the transmission position when sailing, but I can go check.

It is the manual that came with the boat, an O'Day publication. I will look for the paragraph and see if I can scan it. I would assume O'Day checked the equipment manuals before printing this.

Here's the Hurth manual: http://www.c34.org/manuals/Hurth_HB_Transmission_Manual.pdf

Thank you for this manual, I didn't have one and this is a great addition to my documentation file for boat equipment.

I checked the Universal engine manual: it says don't put it in the same position as the boat is traveling! Must have translated that from the original Euclidian!!!

Why would the engine guy care what position it is in if the motor will not turn over? Perhaps the loads on the transmission input shaft spline will cause some wear, otherwise I doubt the compressive and tension loads on the connecting rods will be a problem as they will see higher forces in operation. Besides in reverse these forces should be the same just in opposite directions. Assuming a static propeller (not turning) the forces from the flow stream will cause a torque in the shaft in the same direction whether in forward or reverse. Having the transmission in reverse should cause the torque transmitted to the input shaft to be in opposite direction than in forward gear. So the question of the day is why is this important?