Flex Coupling With Flex Engie Mounts And Flex Stuffing Box

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sg2012

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Hi,
I have sailboat with volvo d2-40 fitted with the original flex engine mounts, and flex stuffing box (buck algonquin packing connected with rubber hose). I am thinking of adding R&D flex coupling, primary to act as a drive saver (it suppose to be relatively stiff). In the volvo Installation manual it says: "When using a flexible shaft seal and flexible engine
suspension, a flexible shaft coupling must not be fitted". reading around it seems this Installation is common, but still no conclusive answer.
Ill appreciate your advice please.
Thanks
Sg
 
I fitted a R&D flexible shaft coupling last winter to see if it would reduce resonance at certain revs. It did and the whole rev range is now much smoother. I have yanmar 2gm20 sitting on flexible mounts with a traditional stuffing box with rubber hose to stern tube and a P bracket.
I think the stuffing box has nothing to do with it as it provides no support to the set up.
 
Volvo information doesn't cover all installations. We have flexible engine mounts + flexible stern gland but, what's not evident until everything is uncoupled is that we have a bearing in the front end of the stern tube, in addition to the cutless on the P bracket so, the shaft isn't free to move with the engine. We have R & D flex coupling.
 
The basic rule of thumb is that of the three elements between mounts coupling stern gland one must be solid to avoid the whole lot dancing about .
However R&D I believe that their couplings are rigid enough to hold the system together .
A quick call to R&D would confirm this .
 
Thank you for your replies,
I think I have the same setup as Spyro
I heard about the rule of the tumb -> too much freedom will let the engine and the system dance too much. I am hopping the R&D will be stiff enough. I sent them an email few days ago and still waiting for a reply (maybe still in vacation). I will update with their answer and with the result (my boat is currently out of the water).
 
here is the answer from R&D:
"The problem is it is possible to get the coupling to run excentrically if it is not registered side to side like some products.
Our coupling has a male register one side and a female the other so that it maintains it concentricity to the axis of both shafts therefore you can use our coupling."

so we are good
thanks everyone!
 
sg2012 said:
here is the answer from R&D:
"The problem is it is possible to get the coupling to run excentrically if it is not registered side to side like some products.
Our coupling has a male register one side and a female the other so that it maintains it concentricity to the axis of both shafts therefore you can use our coupling."
Click to expand...

Well, that says it all. :rolleyes:
 
Couplings

VicMallows said:
Well, that says it all. :rolleyes:
Click to expand...

I can't figure out if VicMallows is being sarcastic or if he means it.
I certainly can't figure out the quote from R&D. The word "registered" has me confused. Does that mean restrained as in some movement permitted but not much or does it mean held with no movement allowed.
How does a male register and a female register work? someone please explain olewill
 
William_H said:
I can't figure out if VicMallows is being sarcastic or if he means it.
I certainly can't figure out the quote from R&D. The word "registered" has me confused. Does that mean restrained as in some movement permitted but not much or does it mean held with no movement allowed.
How does a male register and a female register work? someone please explain olewill
Click to expand...

A spigot- male on one, female on t'other half coupling.
 
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