Bukh DV20 question

[Magaz97]

When sailing, with the engine not running, do I put it in neutral and let the prop spin, or do I engage a gear (forward or reverse)?

Will it make a difference to the engine and gearbox?

Thanks for your input.

 

[Rafiki]

In gear forward !

 

[RobBrown]

Well I have a Bukh 20 and I normally freewheel when sailing to reduce drag. SFAIAA, no requirement to lock for gearbox reasons (BW6), unlike some Volvos.

The comment that free spinning prop has less drag usual initiates a long debate, but the tank tests have it well established

 

[30boat]

Well I have a Bukh 20 and I normally freewheel when sailing to reduce drag. SFAIAA, no requirement to lock for gearbox reasons (BW6), unlike some Volvos.

The comment that free spinning prop has less drag usual initiates a long debate, but the tank tests have it well established

The only problem with that is the increased wear on the gearbox bearings plus the cutless bearing and shaft seal.I always engage reverse when sailing.

 

[SimonJ]

I always leave mine (Bukh 20) in gear to avoid wear on the rotating parts. Usual advice is to go into astern after stopping engine. I do not like the loud clunk when you do that, so these days I stop the engine while still ingear ahead = no clunk and no rotation & then blades fold! If this is a bad idea perhaps someone will say (& why!)

 

[A_Sails_Pace]

I'm finding so many differing opinions on this. I'm trying to work out if I should be leaving my DV20 in neutral whilst sailing, and I'm wondering what the best practice is whilst at a mooring buoy as well?

 

[vyv_cox]

I'm finding so many differing opinions on this. I'm trying to work out if I should be leaving my DV20 in neutral whilst sailing, and I'm wondering what the best practice is whilst at a mooring buoy as well?

Provided that lubricant is splashed onto the bearings, which I belief is the case with the Bukh gearbox, there is absolutely no issue with bearing life. SKF will tell you that the life of small bearings under load is infinite. A few hours unloaded is negligible.
The drag of a rotating prop is tiny compared with a fixed one.

 

[davidej]

Well I have a Bukh 20 and I normally freewheel when sailing to reduce drag. SFAIAA, no requirement to lock for gearbox reasons (BW6), unlike some Volvos.

The comment that free spinning prop has less drag usual initiates a long debate, but the tank tests have it well established

Can't see why! makes obvious sense.

That is the bit about drag. But you have to wonder whether the wear on the cutless , stern seal etc outweighs that.

 

[Poignard]

Is a freewheeling propeller more likely to catch a rope than a fixed one?

 

[rotrax]

The Bukh DV20 fitted to Ella, our Kiwi based Hartley 32 has the Bukh oil filled stern seal. After I added a remote Narrowboat type greaser, but filled with oil, it has been perfect. We freewheel the prop when sailing. A turn down before and after using it seems to be perfect.

There is no movement in the cutlass/shaft area after seven seasons, addmittedly seasons of short use.

It is a simple boat, it does not have self tailing winches, and keeps our sailing skills up.

 

[oldharry]

Is a freewheeling propeller more likely to catch a rope than a fixed one?

I am an 'in gear' sailor for that very reason. Cutless wear, bearing wear contribute, but a rope catching a rotating prop will inevitably get wound on to it, making it more difficult to free. A fixed prop it will snag a blade, and that is all, meaning you are far more likely to be able to hook it off again. Not every time, but it increases the odds of getting free quickly.

 

[Poignard]

The Bukh DV20 fitted to Ella, our Kiwi based Hartley 32 has the Bukh oil filled stern seal. After I added a remote Narrowboat type greaser, but filled with oil, it has been perfect. We freewheel the prop when sailing. A turn down before and after using it seems to be perfect.

There is no movement in the cutlass/shaft area after seven seasons, addmittedly seasons of short use.

It is a simple boat, it does not have self tailing winches, and keeps our sailing skills up.

 

[DMN]

I have a folding two blade Gori prop on shaft to Yanmar. I always lock it in gear when sailing.