I am relatively new to sailing with an inboard engine. Should the transmission be left in gear when sailing to reduce bearing and seal wear (increasing drag?), or should the transmission be in neutral, reducing drag, increasing wear, and creating a small amouont of noise from the turning shaft ?
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transmission when sailing
Don't know what transmission you have, so I'm not sure this will apply. My Cat 30 has a Universal M25 engine with a Hurth HBW-50 transmission. The manual says to leave the transmission in neutral while sailing or in reverse if you want to keep the prop stationary. It warns to never sail with the transmission in forward as it will damage the gears. For what it's worth, I leave mine in neutral. Hope that helps, Ron
Don't know what transmission you have, so I'm not sure this will apply. My Cat 30 has a Universal M25 engine with a Hurth HBW-50 transmission. The manual says to leave the transmission in neutral while sailing or in reverse if you want to keep the prop stationary. It warns to never sail with the transmission in forward as it will damage the gears. For what it's worth, I leave mine in neutral. Hope that helps, Ron
Be careful with non-folding prop
I agree with the previous post...use reverse only. This WILL increase your drag, however. Also, be careful when doing this with a non-folding prop. I have been using reverse for years to lock the shaft with a folding prop, and when I did this on a 361 this summer with the std fixed prop, the gearshift was very hard to move out of reverse as the gearbox was back-loaded due to hydrodynamic forces on the prop. Engaging the starter momentarily while GENTLY forcing the gearshift back to neutral was the only way to get it back into neutral. Good luck! Tim
I agree with the previous post...use reverse only. This WILL increase your drag, however. Also, be careful when doing this with a non-folding prop. I have been using reverse for years to lock the shaft with a folding prop, and when I did this on a 361 this summer with the std fixed prop, the gearshift was very hard to move out of reverse as the gearbox was back-loaded due to hydrodynamic forces on the prop. Engaging the starter momentarily while GENTLY forcing the gearshift back to neutral was the only way to get it back into neutral. Good luck! Tim
Confused?
Reading the last post, I was under the assumption that with a folding prop you would place the transmission in neutral. Thats the whole idea of folding props is that they fold up while the engine is stopped. Did I miss something here??? Jim "Confused as Always" S/V Java
Reading the last post, I was under the assumption that with a folding prop you would place the transmission in neutral. Thats the whole idea of folding props is that they fold up while the engine is stopped. Did I miss something here??? Jim "Confused as Always" S/V Java
prop drag
Believe it or not, there is more drag induced with a free spinning prop than with one locked in gear. Free spinning is also bad for the gearbox. For it to be locked, most transmissions need to be put in reverse. In regards to folding props, they should be locked with the blades folded in the verticle position. You'll need to mark the shaft and then set it by hand, however it will prevent one blade from flopping down while sailing in light air and increasing drag.
Believe it or not, there is more drag induced with a free spinning prop than with one locked in gear. Free spinning is also bad for the gearbox. For it to be locked, most transmissions need to be put in reverse. In regards to folding props, they should be locked with the blades folded in the verticle position. You'll need to mark the shaft and then set it by hand, however it will prevent one blade from flopping down while sailing in light air and increasing drag.
Transmission lubrication
Certain transmissions require the engine in operation to maintain proper lubrication. On my Catalina 320 with a Yanmar engine, that is clearly the case. Hence, those manufacturers recommend engaging in reverse gear while sailing with the engine off. Engaging the transmission in forward while sailing clearly allows prop/shaft spin, so that won't satisfy the criteria. The thing to do is to check with your engine manufacturer, giving them the engine/transmission models. And, I've never had any difficulty disengaging the transmission from reverse in order to start the engine while sailing. As a matter of fact, while under way I've found it seems easier on the drive chain to start the engine while still in reverse, then go smoothly into neutral and then to forward. That way the prop shaft isn't rotating when you engage the transmission (as it would be if you shifted into neutral before starting). --Ron
Certain transmissions require the engine in operation to maintain proper lubrication. On my Catalina 320 with a Yanmar engine, that is clearly the case. Hence, those manufacturers recommend engaging in reverse gear while sailing with the engine off. Engaging the transmission in forward while sailing clearly allows prop/shaft spin, so that won't satisfy the criteria. The thing to do is to check with your engine manufacturer, giving them the engine/transmission models. And, I've never had any difficulty disengaging the transmission from reverse in order to start the engine while sailing. As a matter of fact, while under way I've found it seems easier on the drive chain to start the engine while still in reverse, then go smoothly into neutral and then to forward. That way the prop shaft isn't rotating when you engage the transmission (as it would be if you shifted into neutral before starting). --Ron
also had problems shifting
We have had problems shifting the transmission into neutral after sailing with the reverse gear engaged. I usually start the engine in gear and then can shift into neutral.
We have had problems shifting the transmission into neutral after sailing with the reverse gear engaged. I usually start the engine in gear and then can shift into neutral.
My contribution
Tom, I have a program which calculates props for yachts. On the printout sometimes it says to leave the prop to spin whilst sailing and other times it says to lock the prop. This is all in the interests of reducing drag and takes no account of whether the gearbox will suffer or not. I have not been able to determine which props need to be locked and which are best left to spin, but it does seem that there is no certainty that a free spinning prop causes less drag. I have tried both when sailing against another boat of identical speed (over 60 miles in lightish conditions) and found no conclusive difference. What I do know is that now I have a feathering prop the boat's performance is transformed. Yanmar say to engage reverse and that is what I do. It prevents the prop from turning and forces it to feather. Same for folders. When sailing I also start in reverse in preference to wrenching the box into neutral and I suggest this is best practice for you also. Regards,
Tom, I have a program which calculates props for yachts. On the printout sometimes it says to leave the prop to spin whilst sailing and other times it says to lock the prop. This is all in the interests of reducing drag and takes no account of whether the gearbox will suffer or not. I have not been able to determine which props need to be locked and which are best left to spin, but it does seem that there is no certainty that a free spinning prop causes less drag. I have tried both when sailing against another boat of identical speed (over 60 miles in lightish conditions) and found no conclusive difference. What I do know is that now I have a feathering prop the boat's performance is transformed. Yanmar say to engage reverse and that is what I do. It prevents the prop from turning and forces it to feather. Same for folders. When sailing I also start in reverse in preference to wrenching the box into neutral and I suggest this is best practice for you also. Regards,
Prop Drag
Don, Thanks for your input. I have a Hunter 46, with a Yanmar diesel, that I sail in Lake Erie and was advised to put the shift lever in reverse when under sail. I also restart the engine with the transmission in revese and move it to neutral after starting. The shift lever resistance is reduced with the engine running. I recently got a Max-Prop, which I will install in the Spring before my boat goes back in the water, and I was wondering if it was necessary to put the shift lever in reverse. You have answered my question and I thank you. My next question for you is, what is a reasonable expectation for speed increase using the feathering propeller? Hnels@earthlink.com
Don, Thanks for your input. I have a Hunter 46, with a Yanmar diesel, that I sail in Lake Erie and was advised to put the shift lever in reverse when under sail. I also restart the engine with the transmission in revese and move it to neutral after starting. The shift lever resistance is reduced with the engine running. I recently got a Max-Prop, which I will install in the Spring before my boat goes back in the water, and I was wondering if it was necessary to put the shift lever in reverse. You have answered my question and I thank you. My next question for you is, what is a reasonable expectation for speed increase using the feathering propeller? Hnels@earthlink.com
Stopped with blades vertical
As Capt Dave noted, most of the time you would want to lock the shaft with the folding blades vertical, but with my new Flex-O-Fold geared prop, I have found both blades will always fold with any kind of slipstream force on them, so that's probably not as necessary as it used to be. Heck, when I installed the thing, it was so well balanced that both blades would go to the folded position in any rotational position with the boat on the hoist! As I no longer race (with my boat), I'm not too concerned with getting the blades in the "perfect" position, I just lock it in reverse after shutting down, and ALWAYS start in neutral as there is never a backload on the gearbox that prevents shifting. Tim
As Capt Dave noted, most of the time you would want to lock the shaft with the folding blades vertical, but with my new Flex-O-Fold geared prop, I have found both blades will always fold with any kind of slipstream force on them, so that's probably not as necessary as it used to be. Heck, when I installed the thing, it was so well balanced that both blades would go to the folded position in any rotational position with the boat on the hoist! As I no longer race (with my boat), I'm not too concerned with getting the blades in the "perfect" position, I just lock it in reverse after shutting down, and ALWAYS start in neutral as there is never a backload on the gearbox that prevents shifting. Tim
How about Volvo auxilliaries?
Does anyone on the list know what is correct for a Volvo MD7B diesel with a Volvo transmision (not a sail drive)? That is the engine in my Islander Bahama 30. I have the Volvo user manual, but I don't believe it addresses this issue. Wulfe s/v Jenny-Anne Lake Texoma
Does anyone on the list know what is correct for a Volvo MD7B diesel with a Volvo transmision (not a sail drive)? That is the engine in my Islander Bahama 30. I have the Volvo user manual, but I don't believe it addresses this issue. Wulfe s/v Jenny-Anne Lake Texoma
Volvo Trans
I have asked several people this question regarding my Volvo 2003T/Volvo Trans. I was told to let the fixed prop spin and run the engine every 8-10 hours to cool it down. With a folding prop, I was told to put it in reverse. I've been letting mine spin, even though the hum from the shaft makes me shudder.
I have asked several people this question regarding my Volvo 2003T/Volvo Trans. I was told to let the fixed prop spin and run the engine every 8-10 hours to cool it down. With a folding prop, I was told to put it in reverse. I've been letting mine spin, even though the hum from the shaft makes me shudder.
Feathering propeller
Hobby....I had a MaxProp on my H340 and it was one of the best investments I made. Now have a new H426 on order and first item will be a Maxprop. I found that when under sail, I'd shift to neutral and the prop would immedeately feather to the low drag position and the prop shaft doesn't move. But it also didn't matter if the boat was left in gear or not. As soon as the shaft stopped rotating the prop would move into neutral (or feathered) position. In the Maxprop manual they explain a procedure that will insure the blades move into this position for sailing. I found I gained about .3kt in sailing speed. But the biggest advantage was backing or stopping the boat with reverse. You now have a prop that's 90% efficient in reverse (versus about 20% with fixed pitch). You can stop on a dime and back in a straight line.
Hobby....I had a MaxProp on my H340 and it was one of the best investments I made. Now have a new H426 on order and first item will be a Maxprop. I found that when under sail, I'd shift to neutral and the prop would immedeately feather to the low drag position and the prop shaft doesn't move. But it also didn't matter if the boat was left in gear or not. As soon as the shaft stopped rotating the prop would move into neutral (or feathered) position. In the Maxprop manual they explain a procedure that will insure the blades move into this position for sailing. I found I gained about .3kt in sailing speed. But the biggest advantage was backing or stopping the boat with reverse. You now have a prop that's 90% efficient in reverse (versus about 20% with fixed pitch). You can stop on a dime and back in a straight line.
Answer for Hobby
Hobby, Your Maxprop will do wonders for your sailing. It is difficult to estimate the potential speed increase but I had one on my last boat and, as a keen racer, I did some calcs for my 30' Ron Holland 1/2 tonner as was. The greatest percentage increase came when the weather was light. Under those conditions the hull resistance is quite low so the fixed prop represented a significant proportion of the total drag and feathering it made a big difference. When the hull is moving at 'hull speed' it is making considerable waves, the water flow is not laminar and it is moving plenty of water about. Under these conditions the extra drag from a fixed prop is less significant than before when expressed as a percentage of total hull drag. Also the rig is providing many horsepower to overcome this fixed prop drag. For my half tonner the gain was about 10% in drifting conditions and approx 5% when sailing hard. One way to look at it is that the race handicappers allow a boat 2.5% if she has a 3 bladed fixed prop, 2.0% for a two bladed fixed, 0.5% for a feathering or folding prop and zero for an outboard which can be lifted clear of the water. The old IOR had a fancy formula which I cannot remember but it amounted to just about this. I reckon on average I get about 1/2 knot more since fitting a feathering 3 blader on my 376. The speed increase manifests itself in a number of ways. First, I am usually moving faster than others around me - which annoys them; second, the performance under headsail alone is now impressive; third, my journey times are only slightly improved but the boat feels more alive and is much more pleasant to sail. Think of towing a bucket (and try to pull it in) to get some idea of what a fixed prop costs. Lastly I can now do clever mooring tricks in our very crowded marinas because the stopping and backing power is so much improved. Yes but they are dear to buy though!
Hobby, Your Maxprop will do wonders for your sailing. It is difficult to estimate the potential speed increase but I had one on my last boat and, as a keen racer, I did some calcs for my 30' Ron Holland 1/2 tonner as was. The greatest percentage increase came when the weather was light. Under those conditions the hull resistance is quite low so the fixed prop represented a significant proportion of the total drag and feathering it made a big difference. When the hull is moving at 'hull speed' it is making considerable waves, the water flow is not laminar and it is moving plenty of water about. Under these conditions the extra drag from a fixed prop is less significant than before when expressed as a percentage of total hull drag. Also the rig is providing many horsepower to overcome this fixed prop drag. For my half tonner the gain was about 10% in drifting conditions and approx 5% when sailing hard. One way to look at it is that the race handicappers allow a boat 2.5% if she has a 3 bladed fixed prop, 2.0% for a two bladed fixed, 0.5% for a feathering or folding prop and zero for an outboard which can be lifted clear of the water. The old IOR had a fancy formula which I cannot remember but it amounted to just about this. I reckon on average I get about 1/2 knot more since fitting a feathering 3 blader on my 376. The speed increase manifests itself in a number of ways. First, I am usually moving faster than others around me - which annoys them; second, the performance under headsail alone is now impressive; third, my journey times are only slightly improved but the boat feels more alive and is much more pleasant to sail. Think of towing a bucket (and try to pull it in) to get some idea of what a fixed prop costs. Lastly I can now do clever mooring tricks in our very crowded marinas because the stopping and backing power is so much improved. Yes but they are dear to buy though!
for olvos use reverse only. Locking it in forward
will wear out the clutch on the drive gear which will run about 685.00 for the part alone on your engine assumoing you have a ms trans which you should for that model.
will wear out the clutch on the drive gear which will run about 685.00 for the part alone on your engine assumoing you have a ms trans which you should for that model.
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