prop shaft length from CB to prop

[letterman]

Is there a standard for the length of the shaft from the cutlass bearing to the prop? Mine is at least 12" and a mechanic said that is wrong.

 

[Ross]

That is quite a bit of over hang depending in shaft size. I would look for the allowable overhang in shaft diameters.

 

[Maine Sail]

Is there a standard for the length of the shaft from the cutlass bearing to the prop? Mine is at least 12" and a mechanic said that is wrong.

1

1 X shaft diameter.

 

[Ross]

The existence of prop walk would seem to indicate a radial load on the propeller shaft. In a similar manner a belt drive presents a radial load on a shaft. Do cutlass bearings wear preferentially on the same side as the direction of prop walk? Or on the opposite side?

 

[Winters Dream]

That is quite a bit of over hang depending in shaft size. I would look for the allowable overhang in shaft diameters.

Ross,

You still haven't changed your Will Rogers quote. It's old and it wasn't that good to begin with. Do you need help?

Bob Lendvay

 

[Ross]

How's this.

 

[DAVA390]

Shinning ?

 

[Ross]

Shinning ?

fixed

 

[redhead78]

Wow that seems long, I was told same as Maine, 1"x shaft diameter. Red

 

[kloudie1]

A picture would be good.. I would think you'd have interference between the rudder and prop if it were hanging back there by 12" !!

 

[Maine Sail]

A picture would be good.. I would think you'd have interference between the rudder and prop if it were hanging back there by 12" !!

I agree, a picture would be great. I can't even fathom a 12" overhang without massive vibration issues. The shaft whip would likely look like a jump rope..

 

[Ross]

With an aperature I am restricted to just enough for a zinc donut between the prop and the stern tube and only enough clearance aft for a prop puller.

 

[Maine Sail]

With an aperature I am restricted to just enough for a zinc donut between the prop and the stern tube and only enough clearance aft for a prop puller.

This is why the Algonac is a popular puller with boat yards...

 

[Roger Long]

1 X shaft diameter.

That's the proper standard but you evidently can get away with a lot of standards violations with low horsepower. The approximately 3" between my stern bearing and prop (1" shaft - 20 hp) were high on the "Must Fix" list when I bought the boat but the boat runs very smoothly and I've never seen any sign of a problem. It would probably not run as smoothly if the overhang was corrected because the prop would be closer to the strut. I'm going to leave it as it is but I still wouldn't recommend setting up a drive line that way.

 

[Ross]

A check with a machinist will tell you how much shaft you can extend from a lathe chuck and still get accurate turnings.