Prop spins quickly in neutral

[zenoahphobic]

Ah, but reverse and forward gears are at all times meshed to drive pinion! In affect cancelling each other!
What makes the prop always turn in the same direction ( forwards) then ?????

[zenoahphobic]

Think Julius Sumner Miller "why is it so?" Explained this on TV in the sixties!

[tmann45]

Which creates more drag in the water or in the air when the motor is not running?

A propeller that is allowed to turn or one that is not allowed to turn.

A lot (most?) of the time it is the propeller that is allowed to turn. It depends on the propeller and I'm assuming boat props. That is why cruising sailbotes have a shaft brake.

[zenoahphobic]

A lot (most?) of the time it is the propeller that is allowed to turn. It depends on the propeller and I'm assuming boat props. That is why cruising sailbotes have a shaft brake.

Is this shaft brake to reduce drag?
I have heard of folding prop in sailboat applications and can see where a brake might be used in larger boats, in application where reverse is required, or where submarines require to be "quiet" from enemy detection.
Not that familiar of application of a shaft brake in yachts ?

[DennisG01]

Often times, the reason for stopping the shaft from turning (with an inboard or v-drive engine) is because without the engine turning, the transmission won't get any cooling water pumped through it. I suppose the same goes for the shaft seals. If there's no actual "lock" (like a disc brake, sort of), then some will put it in reverse or manually lock it with a strap wrench/visegrip/some type of wedging.

[rodbolt17]

dang near 4 pages of an entirely normal outboard
***.

[DennisG01]

dang near 4 pages of an entirely normal outboard
***.

It's one of those "morphing" threads. I'm glad to have learned that my prop spinning (although faster than I've ever seen one, personally) "issue" is OK. But after that it's been, at least for me, some enjoyable conversations and an interesting read.

[zenoahphobic]

It's one of those "morphing" threads. I'm glad to have learned that my prop spinning (although faster than I've ever seen one, personally) "issue" is OK. But after that it's been, at least for me, some enjoyable conversations and an interesting read.

Nobody has cottoned on that it is gyroscopic forces that makes the propellor turn (from engine running, turning in one direction).
It has nothing to do with with the physical connection in the gear box, not viscosity etc.
I would imagine if the pinion gear was removed and even the driveshaft shortened to have no protrusion into the gearbox, the prop shaft will still turn in a particular direction, as the Professor would say, "in harmony with the engine"

[zenoahphobic]

Now what happens when you put a LH propellor on a RH engine?
Or can anyone tell me in which direction does the prop turn on a LH rotating engine in freewheeling on the earmuffs situation??

[DennisG01]

Now what happens when you put a LH propellor on a RH engine?
Or can anyone tell me in which direction does the prop turn on a LH rotating engine in freewheeling on the earmuffs situation??

It would turn the same direction as a RH prop since the engines still turn the same direction. It's only the lower unit gears that are cut in the opposite direction. Did I get that one right?

[zenoahphobic]

It would turn the same direction as a RH prop since the engines still turn the same direction. It's only the lower unit gears that are cut in the opposite direction. Did I get that one right?

Yep!
A LH engine looking at prop , appears to be in reverse gear. Whereas a more common RH engine appears " more normal" when the prop is freewheeling forwards. Just luck of the draw, because if opposite ( backwards) more people will be concerned, putting questions on forums " why is my prop going backwards when on earmuffs?"

[zenoahphobic]

dang near 4 pages of an entirely normal outboard
***.

You just want a broken one to fix!