Locking the prop's shaft -- damage?

[Lapintos]

We have 3YM30 in our sailboat. I know that we need to lock the shaft while sailing by putting the gear in reverse position to avoid any damage to the transmission. But my question is, when we are motoring, open both sails then stop the engine, the speed of the boat could be around let say 3 knots... So how to put in reverse position without make any damage to the transmission? The shaft is spinning well at that speed and lock suddently may not cause any damage? Thank you



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[MBWhite]

When you are sailing and turn the motor off, does the prop freewheel all the time when in gear (forward)? If not just turn off the engine and when it stops just move from forward to reverse in a smooth movement. If you have to slow down to get it to stop just try heading up and catch it before the boat stalls so you still have a tiny bit of headway to turn and pick up your wind again.

[Lapintos]

Thank you for your quick reply.



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[UNCIVILIZED]

Always just used my sneaker, with a foot in it, or a gloved hand to stop the spinning. Odds are, so long as your shaft's easy to reach, that a similar technique will work on yours. Or, size a 2x2 or spare broom handle with some rope/knotwork around it's end to slide into place, & use a very mild bit of leverage on it, to let the friction from the knotwork stop the shaft.

BTW, it speaks well of how slick your driveline is, that your prop free wheels so easily. Ditto on your other underwater appendages not creating much drag, if the water flow so easily gets to the prop at speed.

[Lapintos]

Thank you



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[carstenb]

This will depend on the typeof prop you have.

If you have a feathering prop (say a maxprop) you should not put the tranny in reverse to "lock" the tranny. The feathering type of props should feather by themselves (if not turning off the engine while in gear at about 3 knots will feather it.)

Locking the tranny with a feathering prop will cause the prop to go into reverse mode and cause a lot of drag (not to mention potential dmage to your tranny)

[Lapintos]

It is a 3 fixed blade prop


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[bsurvey]

do it very slowly to stop any chance of grinding the gears OR stop the engine in forward gear the shaft should stop as it can't turn the engine and the transmission. then shift through neutral into reverse

[Cheechako]

I've always had to go into reverse to feather a max prop. It's a rare day it will feather without that.

[sailr69]

a lot will depend on your make of transmission. hurtz or ZF always has the gears in mesh. shifting gears is done via clutches . these trans. can be shifted from forward to reverse at full speed. manufactures say when sailing, have the trans. in reverse to stop the shaft and neutral if you want it to turn. never leave it in forward gear without engine running while sailing.

[Maine Sail]

Originally Posted by Lapintos

We have 3YM30 in our sailboat. I know that we need to lock the shaft while sailing by putting the gear in reverse position to avoid any damage to the transmission. But my question is, when we are motoring, open both sails then stop the engine, the speed of the boat could be around let say 3 knots... So how to put in reverse position without make any damage to the transmission? The shaft is spinning well at that speed and lock suddently may not cause any damage? Thank you



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Actually Yanmar does not want it locked in reverse. They want it in neutral or to use a shaft brake..

[Miker1944]

We always "free wheel" our prop, as our Yanmar Manual recommends. Have never had a bit of problem from doing this.

[jacaranda]

we engaged reverse to stop the prop turning whilst sailing at 6 kn but it locked solid and we could not get it back into neutral to start the engine and succeeded in burning out the starter motor trying to start the engine whilst sailing

[clownfishsydney]

We have Autostream self-feathering props. After not using for a while, we have to engage reverse (as per manual) to cause them to feather. After a bit of use this does not seem to be required.

[a64pilot]

Originally Posted by jacaranda

we engaged reverse to stop the prop turning whilst sailing at 6 kn but it locked solid and we could not get it back into neutral to start the engine and succeeded in burning out the starter motor trying to start the engine whilst sailing

My boat manual recommends selecting reverse to stop the prop, and indeed if your
going fast it is difficult to get it back in neutral, but if you just slow down, it's easy