In gear or not

[PabloPicasso]

Sailing/racing with a fixed prop on a saildrive.

Faster in gear or neutral and allowed to spin?

Volvo md2010 with a 120 saildrive

The owner's manual says in gear for folding prop and nuetral for a fixed one. It doesn't give a reason why/why not for the fixed prop. Anyone have an opinion?

 

[Tranona]

Despite the warning many people put in gear with a fixed prop to stop the noise when sailing over about 5.5 knots. Does not seem to do any harm. You may not be bothered too much about the noise so let it spin. However fitting a Flexofold will be the best thing you can spend your money on. Leaving it in gear when sailing is to ensure the blades stay closed.

 

[Poignard]

Yes. If the prop cannot rotate it adds drag. It is trying to rotate the boat!

 

[Stemar]

However fitting a Flexofold will be the best thing you can spend your money on

There was an article in a yottie comic a few years ago about downwind sails - spinny or asymmetric, etc. The outcome was neither - spend your money on a folding prop, because you get the benefits at all points of sail

 

[Tranona]

Yes, and at all speeds without any effort. Good evidence it reduces passage times by about 10% or daily runs by similar if you are crossing oceans.

 

[Refueler]

Folder - In gear as another says to hold blades closed.

Fixed - out of gear ... some gearboxes do not like being spun - so I'm told.

Me ? I have one boat with fixed - out of gear ...another boat with folder and TBH - I forget and it usually is out of gear as well ...

 

[Concerto]

Fit a folding prop. Coming from a racing background, I would never sail with a fixed prop due to the extra drag. My Gori 2 bladed folder only needs to be put in reverse to stop it spinning and close the blades. Then I move it to neutral and the blades remain closed as they are geared together. Works perfectly in forward and reverse, plus I sail faster in all conditions and points of sail. On two different occasions I sailed against other Fulmars. One was a fin with a fixed 2 bladed prop and the other was a twin keel with a fixed 3 bladed prop. Each time I had an identical sail plan. The fin keel I out sailed by about a mile in a 8 mile leg, including sailing through their lee. The twin keel tried to stay with me but could only do it by turning the engine on.

Returning to the OP's question. Generally there is slightly less drag from a spinning prop compared to one in gear.

 

[KevinV]

This was put to bed years ago - if your gearbox will allow it, and you can bear the noise - let it spin, it's a HUGE difference in drag.

Lock your prop, or let it spin?

 

[samfieldhouse]

Yachting Monthly did a fairly rigorous test on this (Lock your prop, or let it spin?.)

Basically, let it spin. But that depends how you feel about wear.

 

[PCUK]

I used a folding prop'on a 14 ton displacement motor boat with a 30hp wing engine. First was a two blade Flexofold. This gave four knots max' but I later fitted a three blade Volvo and this gave 6.5 knots and strong reverse bite. Main engine at 300hp gave 12 knots.

 

[samfieldhouse]

On the folding/feathering debate:
A folding prop physically wouldn’t fit my boat, it would hit the skeg.
I weighed up a feathering prop but in the end opted for new sails, which for the type of cruising I do has been transformative and the better investment.

 

[Plum]

- let it spin, it's a HUGE difference in drag.

Lock your prop, or let it spin?

Not in my case. I sailed close to, but not in the windshadow of, another boat for 30 mins and every 5 minutes I alternated between fixed and rotating 3-blade prop. There was no discernable difference in relative speed.