Shaft Collar ??

[expressboy]

Does anyone know what the shaft collars that are mounted within a foot of the point the shafts go through the hull do??

I am not referring to the shaft collar zincs.. these are about 3/4" wide and 3/4" larger than the shaft..
I have never seen anything like these on any other boat
EXPRESSBOY

 

[electricaldoctor]

I don't know what you are referring to, but I hope that your cutlass bearings have not slld out.

 

[1956olds]

First off they arent zinks,they are to aid in cooling of the packing gland by forcing water forwards into the shaft tube.I am not sure how far from the point of entry they are supposed to be but that is what i have been told by my marina mechanic who also teaches marine repair at saginaw valley state university.

 

[fwebster]

Collars also prevent the loss of a shaft in the event that a coupler comes loose underway. Many older couplers are only attached to the shaft with a key and 2 set screws, so the collar is a safety measure since it will stop at the strut and keep the shaft from being lost.

 

[expressboy]

That was my original thought.... but there are two problems with this....

1. they are 4' above the prop strut and the little bronze thing that makes the boat turn when you turn the steering wheel is only 6" behind the prop so the shaft cannot go too far ( as long as the thing that is like a magnet to solid objects and people that is mounted on the end of the shaft is still there ) !

2. hydrodynamics tell me that a collar 6" behind the point the shaft goes through the bottom cannot do jack to push water forward whilst underway...
( at 20+ kts. )

my first thought was a safety to keep a shaft zinc from sliding forward and grinding a hole in the hull but I think it would slide back to the strut if it was so inclined to move in the first place..

any other thoughts.... anyone??

EXPRESSBOY

 

[expressboy]

I don't know what you are referring to, but I hope that your cutlass bearings have not slld out.

nope... cutlass bearings are doodads that are bronze tubes with a rubber internal hub and are 6"+ long .. this is a bronze clamp that is 3/4" thick... not to mention they ( cutlass bearings ) are on the prop side of this shaft collar and sitting cozy in the struts
Thanks
EXPRESSBOY

 

[Island_Girl]

56olds is exactly right, they are provided to aid in cooling of the packing gland. Assuming your 400EX has "pockets" where the props/shafts reside, this collar is likely set on the shaft close to where shaft intersects the riding plane of the adjoining surfaces. In fact at 20+ knots, its probably more effective.

Collars to prevent shaft loss are typically placed inside the hull in close proximity to the shaft log.