HUNTER 34 Tranny to prop shaft coupler

[cdells]

Good Morning everyone. Can anyone tell me the difference between the coupler showed on Westerbeke's website (Westerbeke 21) and the "Flexible Coupler"? TRANSMISSION - COUPLING - SHIFT - Westerbeke
My coupler has seen better days and I am trying to figure out what I need to buy... if the flexible coupler that sells for 150 is just a newer version of the old coupler (which is $450) then I my choice is clear...but I am sure there is more to it.

 

[Tally Ho]

I don’t know what the difference is between the 2 couplings you referenced…

But I will say that expect you will have a devil of a time getting the shaft and coupler part based on your photo.
I suspect you will not be able to get them apart, and probably should consider replacing the shaft at the same time. If you decide to do that, you can cut the shaft and take it out in pieces much easier.

I was able to press my coupling off (and not nearly as bad as yours), but still scrapped the shaft and replaced the whole thing.

Good luck…


Greg

 

[cdells]

Greg, great videos and thanks for the suggestions! I am hoping to be able to separate the two but if not...Ill have to take the longer route. I just wonder if the flexible coupler is meant to be easier to align (more forgiving) with the transmission.
Thanks again,
SF
Chris

 

[Tally Ho]

I c

Greg, great videos and thanks for the suggestions! I am hoping to be able to separate the two but if not...Ill have to take the longer route. I just wonder if the flexible coupler is meant to be easier to align (more forgiving) with the transmission.
Thanks again,
SF
Chris

I cant figure out what the “flexible” coupler is all about. Not made out of plastic, holes are not slotted (to make it fit more bolt pattern, …

When I have to replace mine next time, I will probably go with a “split” coupler to facilitate removing it. I just removed mine to install a Volvo Penta Dripless shaft log and it took a little work to get it off. So a split coupling may the way to go.

Greg

 

[dmax]

When I asked MaineSail about his opinion on flexible couplers he said he did not recommend them. I went with a split coupler from Buck Algonquin.

 

[cdells]

Despite it going on 3 years now I have finally made some progress. I finally got the old coupler and shaft apart..but there was no saving them. I have replaced the cutlass bearing, shaft seal (with pss), shaft, and coupler...not to mention took the engine out for a partial rebuild, new engine mounts and some paint in the engine bay. I don't quit, but I don't go fast for sure....

As I link the coupler back to the transmission, does anyone know where I can find the clearances. I know there is a specific range but I cant find it in any of the stuff I have. Thanks.
SF
Chris

 

[jssailem]

Congrats on your steady progress.

Here is the fundamental goal. I strove to achieve the 3600 RPM standard of 0.3 mils/1" of coupler.
"The goal of precision shaft alignment is to make the rotational centerlines of the machines collinear when in operation. Doing so minimizes forces being transmitted across the coupling, "

Here is an excellent document on the shaft coupling for a boat.

https://stevedmarineconsulting.com/wp-content/uploads/2019/06/ShaftCouplings179FINAL-PBB.pdf

 

[cdells]

That is perfect, thanks jssailem! I'll keep ya posted!
SF
Chris

 

[smokey73]

@jssailem Thanks for the excellent article. In that document he refers to another document "The Necessity of Straight" for details on shaft alignment. Here is a link to that article.

https://stevedmarineconsulting.com/wp-content/uploads/2014/03/Shaft-Alignment-159-02.pdf

 

[smokey73]

Congrats on your steady progress.

Here is the fundamental goal. I strove to achieve the 3600 RPM standard of 0.3 mils/1" of coupler.

@jssailem Just to make sure I understand the meaning of ".3 mils/1" of coupler for 3600 rpm. We are talking about the outside diameter of the coupler, not the shaft diameter. So for a coupler of 4 inches outside diameter, the angular alignment would be 1.2 mils. Is that correct?

 

[jssailem]

That is how I understood the information provided.