I've heard lots of pro's and con's about engaging the transmission while sailing, and I suppose it's specific to certain engines and transmissions. I own a 1990 Hunter 335 with a 2GM Yanmar. Anybody know what is recommended? Cap'n Brent
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Trans
Your trans will be O.K in neutral because it will still be lubed, you will be turning the shaft which will be adding a little more wear to the cutless bearing and packing which is no great concern, so with your trans its really up to you.
Your trans will be O.K in neutral because it will still be lubed, you will be turning the shaft which will be adding a little more wear to the cutless bearing and packing which is no great concern, so with your trans its really up to you.
Reverse
Gordon Torresen of Torresen Sailing page and a Yanmar Service Center says In Reverse. Just remeber to put in neutral when starting.
Gordon Torresen of Torresen Sailing page and a Yanmar Service Center says In Reverse. Just remeber to put in neutral when starting.
REVERSE
If you leave it in reverse, you may want to "mark" the shaft with a piece of tape to show when the prop (assume 2-bladed) is in vertical alignment. Moving it to that position will provide minimum drag underway. If you have a 3-bladed prop it really doesn't matter! Good Luck and Smooth Sailing! Tim Leighton (S/V "Magic")
If you leave it in reverse, you may want to "mark" the shaft with a piece of tape to show when the prop (assume 2-bladed) is in vertical alignment. Moving it to that position will provide minimum drag underway. If you have a 3-bladed prop it really doesn't matter! Good Luck and Smooth Sailing! Tim Leighton (S/V "Magic")
Warning
I have tried sailing with my 2GM20 in reverse. When I was ready to start the engine, I tried to shift to neutral but it would not shift until I stopped the boat movement(removed pressure on the transmission). Be careful when you do that because if you need to start the engine in a hurry you'll have a problem. I was planning on trying sailing with the transmission in forward next but after my experience in reverse, I decided to leave well enough alone.
I have tried sailing with my 2GM20 in reverse. When I was ready to start the engine, I tried to shift to neutral but it would not shift until I stopped the boat movement(removed pressure on the transmission). Be careful when you do that because if you need to start the engine in a hurry you'll have a problem. I was planning on trying sailing with the transmission in forward next but after my experience in reverse, I decided to leave well enough alone.
transmission shift postion while sailing
This is one of those recurring questions that would certainly benefit from a FAQ section Phil. Yanmar says reverse. Reason being that the transmission gets its lubrication from the turning forward and reverse gears which both turn constantly with the engine and which dip into the transmission oil and send it all over the internal gears and bearings. When the prop shaft turns but the engine doesn't, then the output shaft bearings are operating without a replenishing supply of lubricant. Probably of small import unless sailing in neutral continues for many many hours or days. Reason that it tends to be hard to shift out of reverse when considerable way is on is that the servo mechanism of the clutch driven by the twist put on the shaft by the prop tightens up the clutch. Usually this shouldn't be of much significance since normally the engine is called for when there is little or no way on. Here is a link to a detailed explanation of the transmission that I put in the photo forum a year or two ago and found just now from the archives. The included picture shows the transmission geometry with the drive cone clutch engaging the forward gear. In neutral, the drive cone would be moved slighty aft so theat the output shaft can turn freely. The worse of all worlds is to sail with the shifter in forward for now the servo effect of the twisted splines is working to loosen the clutch and the clutch cone will probably slip under the pressure of the propeller. Anybody wanting to sail with the transmission in forward should at least check the shaft while under way. If it is turning, bad things are happening in the transmission.
This is one of those recurring questions that would certainly benefit from a FAQ section Phil. Yanmar says reverse. Reason being that the transmission gets its lubrication from the turning forward and reverse gears which both turn constantly with the engine and which dip into the transmission oil and send it all over the internal gears and bearings. When the prop shaft turns but the engine doesn't, then the output shaft bearings are operating without a replenishing supply of lubricant. Probably of small import unless sailing in neutral continues for many many hours or days. Reason that it tends to be hard to shift out of reverse when considerable way is on is that the servo mechanism of the clutch driven by the twist put on the shaft by the prop tightens up the clutch. Usually this shouldn't be of much significance since normally the engine is called for when there is little or no way on. Here is a link to a detailed explanation of the transmission that I put in the photo forum a year or two ago and found just now from the archives. The included picture shows the transmission geometry with the drive cone clutch engaging the forward gear. In neutral, the drive cone would be moved slighty aft so theat the output shaft can turn freely. The worse of all worlds is to sail with the shifter in forward for now the servo effect of the twisted splines is working to loosen the clutch and the clutch cone will probably slip under the pressure of the propeller. Anybody wanting to sail with the transmission in forward should at least check the shaft while under way. If it is turning, bad things are happening in the transmission.
Attachments
Great analysis of tranny operation...
Terry- Based on your analysis & the pics you point to, I agree, Reverse is the way to go. I am curious, though, about oil level in the tranny & how it is effected by engine/tranny fore & aft inclination. Since it looks like cones move on a spline on the output shaft, is it possible that they will revolve (in neutral) through the oil and fling around enough to lube the various bearings & bushings involved? There's no load (to speak of, except for some thrust perjaps), so even an oil mist might be OK. What is the recommended oil? What does the Yanmar manual say on the topic?
Terry- Based on your analysis & the pics you point to, I agree, Reverse is the way to go. I am curious, though, about oil level in the tranny & how it is effected by engine/tranny fore & aft inclination. Since it looks like cones move on a spline on the output shaft, is it possible that they will revolve (in neutral) through the oil and fling around enough to lube the various bearings & bushings involved? There's no load (to speak of, except for some thrust perjaps), so even an oil mist might be OK. What is the recommended oil? What does the Yanmar manual say on the topic?
Transmission oil.
People may correct me but as I recall the recommended oil for the Yanmar tranny is 10-W-30 motor oil. The 15-HP 2-banger we had in Antigone took either 2-1/2 or 3-1/2 quarts and the manual actually said to pour the last half-quart into the tranny. I thought that was a very wise and economical way to go. JC
People may correct me but as I recall the recommended oil for the Yanmar tranny is 10-W-30 motor oil. The 15-HP 2-banger we had in Antigone took either 2-1/2 or 3-1/2 quarts and the manual actually said to pour the last half-quart into the tranny. I thought that was a very wise and economical way to go. JC
Tom- 2gm manual recommendations for oil
My operating manual for 2gm says use same oil as in crankcase. This may not be true for all the Yanmar engines and transmissions. Same manual says 2gm gear case capacity is .25 liter (about 8 oz) to the full mark with 8 degrees inclination. Engine manual says "check the clutch case oil level without screwing in the cap." On the other hand, my operating manual says "For the checking of the amount of lube oil to the reduction and reversing gear case, check with screwing the dipstick." Since the operating manual seems to be imperfectly translated, safest thing would be to measure out .25liter, put it in an empty transmission case, measure the mark on the dipstick with it just sitting in the hole and make a note to repeat that procedure in the future. Tom, I don't have any information that shows the oil level relative to clutch cone. It may very well pick up some oil from a full sump in neutral since the clutch does turn with the propeller. Also, I agree with your comment about there being little or no load on the bearings when free wheeling in neutral.
My operating manual for 2gm says use same oil as in crankcase. This may not be true for all the Yanmar engines and transmissions. Same manual says 2gm gear case capacity is .25 liter (about 8 oz) to the full mark with 8 degrees inclination. Engine manual says "check the clutch case oil level without screwing in the cap." On the other hand, my operating manual says "For the checking of the amount of lube oil to the reduction and reversing gear case, check with screwing the dipstick." Since the operating manual seems to be imperfectly translated, safest thing would be to measure out .25liter, put it in an empty transmission case, measure the mark on the dipstick with it just sitting in the hole and make a note to repeat that procedure in the future. Tom, I don't have any information that shows the oil level relative to clutch cone. It may very well pick up some oil from a full sump in neutral since the clutch does turn with the propeller. Also, I agree with your comment about there being little or no load on the bearings when free wheeling in neutral.
We need someone to actually do it!
I'm thinking about this because most of what I read says that a propeller in the water has the least drag when it is free to turn. This includes the study in Practical Sailor some years ago and Dave Gerr's books. I think it might take someone who actually has a tranny from a 2GM or 3GM in their shop to take a look and say what they see regarding oil level, the cones and possible "spray" lubrication. I'm also at all thinking of this because I will not be able to spring for a low-drag folding or feathering prop for our soon-to-be V32 for awhile. I like to sail and NOT have things like loose leech lines, poorly positioned travellers and draging 2 or 3 bladed (don't know what it has yet) props slowing me down... I think your experiment is the only way to test the oil level Vs. dipstick-position question. Anyone out there recommissioning their boat for the season like to try it and report?
I'm thinking about this because most of what I read says that a propeller in the water has the least drag when it is free to turn. This includes the study in Practical Sailor some years ago and Dave Gerr's books. I think it might take someone who actually has a tranny from a 2GM or 3GM in their shop to take a look and say what they see regarding oil level, the cones and possible "spray" lubrication. I'm also at all thinking of this because I will not be able to spring for a low-drag folding or feathering prop for our soon-to-be V32 for awhile. I like to sail and NOT have things like loose leech lines, poorly positioned travellers and draging 2 or 3 bladed (don't know what it has yet) props slowing me down... I think your experiment is the only way to test the oil level Vs. dipstick-position question. Anyone out there recommissioning their boat for the season like to try it and report?
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