syledis
New Member
Please help an on going row on our boat. When sailing my co-owner insists on putting the engine in reverse when switched off and I think we should put it in neutral. We dont have a folding prop yet.
Thanks
Thanks
Propeller while sailing
- Thread starter syledis
- Start date
shmoo
Well-Known Member
Stop it rotating. While it is rotating the water is doing work on it overcoming friction, wearing out bearings and making noise. The work the water is doing on the prop has to come from somewhere: your sails.
Conrad
Well-Known Member
Hmm, whilst it is still isn't it more like a drogue, I would have thought the going with the flow so to speak would have put less drag on the boats movement.
Perhaps an interesting science project for a student.
I do leave it in gear whilst on the mooring to keep the bearings from wearing out.
Perhaps an interesting science project for a student.
I do leave it in gear whilst on the mooring to keep the bearings from wearing out.
Twister_Ken
Well-Known Member
This is discussed in depth about once every few weeks during the sailing season. The usual conclusion is either to leave in gear, or put it in neutral. Certain people are able to quote their engine manual which definitely says do one, or the other. Others think it is all to do with helicopters crashing. Me, I just dislike the slight rumble, so I reverse it. Unless I forget.
flaming
Well-Known Member
[ QUOTE ]
Me, I just dislike the slight rumble, so I reverse it. Unless I forget.
[/ QUOTE ]
Better yet, get a folding prop and do away with that as well as sailing faster.
Me, I just dislike the slight rumble, so I reverse it. Unless I forget.
[/ QUOTE ]
Better yet, get a folding prop and do away with that as well as sailing faster.
syledis
New Member
Thanks a million for all the responses - there is nothing like a clear and unambiguous answer!!! So I think we will continue to row over it until we can save up and buy a folding prop
Happy sailing
Happy sailing
shmoo
Well-Known Member
[ QUOTE ]
The usual conclusion is either to leave in gear, or put it in neutral.
[/ QUOTE ]
A nicely understated tautology... Take a bow.
The usual conclusion is either to leave in gear, or put it in neutral.
[/ QUOTE ]
A nicely understated tautology... Take a bow.
bedouin
Well-Known Member
There is definitely a benefit in keeping the prop in gear as it stops it rotating and so reduces wear on the bearings, gearbox and so on.
There are lots of arguments about which is the more efficient - but in practice you aren't going to notice the difference.
I, in common with all skippers I know, do stick the engine in reverse
There are lots of arguments about which is the more efficient - but in practice you aren't going to notice the difference.
I, in common with all skippers I know, do stick the engine in reverse
BobnLesley
Well-Known Member
Quote:
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Me, I just dislike the slight rumble, so I reverse it. Unless I forget.
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Agreed
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Me, I just dislike the slight rumble, so I reverse it. Unless I forget.
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Agreed
Sailfree
Well-Known Member
This has been the subject of many studies and previous threads.
The facts are
1. A fixed propeller (not revolving) causes less wear and drag when sailing.
2. A number of modern gearboxes are not suitable/can be damaged if you engage reverse while sailing to lock the prop. (Mine on a 3yr old 75hp Yanmar is like that and in fact if you do engage reverse to lock the shaft the selectors lock up peventing you from engaging neutral before re-starting the engine- we had to start engine while still in astern and then quickly engage neutral then forwards)
3. For these gearboxes that can be damaged the alternative is to fit a shaft brake or folding prop or feathering prop. As a shaft brake is as expensive as a new prop I bought a variprop feathering prop and can now engage reverse to feather the blades and stop the shaft turning and it no longer gets jammed in reverse.
Note on US boats they can only start the engine when neutral is engaged so these new gearboxes are a bigger problem for them.
The facts are
1. A fixed propeller (not revolving) causes less wear and drag when sailing.
2. A number of modern gearboxes are not suitable/can be damaged if you engage reverse while sailing to lock the prop. (Mine on a 3yr old 75hp Yanmar is like that and in fact if you do engage reverse to lock the shaft the selectors lock up peventing you from engaging neutral before re-starting the engine- we had to start engine while still in astern and then quickly engage neutral then forwards)
3. For these gearboxes that can be damaged the alternative is to fit a shaft brake or folding prop or feathering prop. As a shaft brake is as expensive as a new prop I bought a variprop feathering prop and can now engage reverse to feather the blades and stop the shaft turning and it no longer gets jammed in reverse.
Note on US boats they can only start the engine when neutral is engaged so these new gearboxes are a bigger problem for them.
john_morris_uk
Well-Known Member
People argue about it all the time, and after years of reading the arguments and the various bit people have written, I have come to the following conclusions:
If you have a very thin high aspect propellor it's less drag to fix it when sailing (usually by placing the gear lever in reverse.)
If you have a propellor that is low aspect ration and looks like a motor boat propellor it might be less drag to allow it to rotate. However if you do allow your shaft to rotate, you can damage some gearboxes and you certainly have more wear on bearings etc.
Conversely some gearboxes don't like being put in reverse and get stuck 'in gear'. (Normally not a problem - start the engine and it frees up straight away.)
Because of the variables, people can claim that 'their' answer is the right one, and still be wrong in some circumstances.
We bought a feathering propellor and solved all the arguments. We also go a knot faster or more in light winds.
If you have a very thin high aspect propellor it's less drag to fix it when sailing (usually by placing the gear lever in reverse.)
If you have a propellor that is low aspect ration and looks like a motor boat propellor it might be less drag to allow it to rotate. However if you do allow your shaft to rotate, you can damage some gearboxes and you certainly have more wear on bearings etc.
Conversely some gearboxes don't like being put in reverse and get stuck 'in gear'. (Normally not a problem - start the engine and it frees up straight away.)
Because of the variables, people can claim that 'their' answer is the right one, and still be wrong in some circumstances.
We bought a feathering propellor and solved all the arguments. We also go a knot faster or more in light winds.
smeaks
Well-Known Member
We engage reverse to stop the rumble/clicks more than anything (think of all that wear!!!) but i stupidy always leave it not just in gear but with the lever flat, this is ok when you remember to engage neutral to start, but it is a shoch both to the boat and my systems when i forget and start up having the engine immeadiatly start to power right up in astern with the boat charging down the fairway towards home!!! it is amazing how fast i can move from the companion way to the throttle!
aluijten
Well-Known Member
Just to add something to the discussion:
If there would be less drag when the propeller is locked, then why does it rotate when left in neutral?
In other words, why does it start spinning if there is less drag to be experienced by the propeller when not rotating?
Just a question...
If there would be less drag when the propeller is locked, then why does it rotate when left in neutral?
In other words, why does it start spinning if there is less drag to be experienced by the propeller when not rotating?
Just a question...
Tranona
Well-Known Member
Just to add to the confusion, if you have a saildrive, the advice (from Volvo) is to leave it in neutral if you have a fixed blade prop and in reverse if you have a folding prop.
In neutral the rumbling starts just when you are enjoying the results of a well balanced sailboat - 5 knots or so.
They don't say what will happen if you put it in gear, but the cynics (who me?) might think it a good marketing ploy to sell their folding props!
In neutral the rumbling starts just when you are enjoying the results of a well balanced sailboat - 5 knots or so.
They don't say what will happen if you put it in gear, but the cynics (who me?) might think it a good marketing ploy to sell their folding props!
aluijten
Well-Known Member
That is consistent to the idea that a rotating propeller creates less drag that a locked one.
For folding propellers you need to engage reverse to make sure the propeller folds. If you keep it in neutral it will not fold and start spinning (personal experience).
Cheers,
Arno
For folding propellers you need to engage reverse to make sure the propeller folds. If you keep it in neutral it will not fold and start spinning (personal experience).
Cheers,
Arno
syledis
New Member
Thanks again for all the responses. I am still confused, but am coming more to the conclusion that we will have to bite the bullet and get a folding prop. I will cancel our summer hols to pay for it!!
Thanks
John
Thanks
John
chrishelen
N/A
What about the strain on the stern gear if you put it in gear?the water is trying to spin the prop thus causing strain to gears clutch bearings ect,its a chicken/egg situation.
cazzascotta
Active Member
If I remember, Beneteau suggested to one user to put in reverse while sailing.
And so do I, but the last time it happened that while trying to engaging neutral before re-starting the engine, it jammed and wouldn't return to neutral without a great effort on the lever. The engine is a Yanmar 2GM20F and I will not have again that situation.
My questions: is a good thing to start engine while in reverse? Is it better than leaving the shaft turn while sailing? How serious damages can I have with the shaft free to turn while sailing?
And so do I, but the last time it happened that while trying to engaging neutral before re-starting the engine, it jammed and wouldn't return to neutral without a great effort on the lever. The engine is a Yanmar 2GM20F and I will not have again that situation.
My questions: is a good thing to start engine while in reverse? Is it better than leaving the shaft turn while sailing? How serious damages can I have with the shaft free to turn while sailing?
TigaWave
Well-Known Member
Actually on the volvo saildrive of 1991 the gearbox locks up and you can't get it out of gear as one other person has commented.
When the folding prop is fitted the flow of water shuts the prop even if the gears are a bit stiff.
So definately check gearbox manual first, its different for different gearboxes.
When the folding prop is fitted the flow of water shuts the prop even if the gears are a bit stiff.
So definately check gearbox manual first, its different for different gearboxes.
aluijten
Well-Known Member
I'm not sure what engine setup you have, but I recently switched to a Volvo 3 blade folder on a saildrive (after losing a blade of a 2 blade Gori) and despite of being quite unhappy about the loss I did notice a nice performance increase (under power) because of the 3-blade propeller.
That does not mean the Gori was no good though. For 60% of the price of the Volvo is still quite OK, just be very careful with assembling the propeller as the locking screws can fail otherwise (again personal experience /forums/images/graemlins/frown.gif )
Arno
That does not mean the Gori was no good though. For 60% of the price of the Volvo is still quite OK, just be very careful with assembling the propeller as the locking screws can fail otherwise (again personal experience /forums/images/graemlins/frown.gif )
Arno
