driveshaft couplings?

[simon_sluggett]

I have a yanmar single cylinder deisel in my boat which is quite noisy and it has a drive coupling which is a hard polyurathane material (r and d type). I was thinking of replacing it anyway but was wondering if it was worth going for a rubber type coupling - quitelife or vetus type. Do they offer a much quiter life for the extra cost involved.

 

[Tranona]

I have a Bullflex from Vetus on my 1GM. It replaced an R&D. Very satisfied. Said to allow 2 degrees misalgnment but I lined mine up as if it was a solid coupling. My shaft is rigid, that is it has a bearing on the inboard end so it is important for my installation to allow the engine to move wothout moving the shaft. The bearing wore out previously, but after 3 years seems OK with the new coupling.
Hope this helps

 

[Avocet]

I have a 12hp single cylinder and much the same trouble. I fitted Vetus hydraulic egine mounts which made a big difference to structure-borne noise but allowed the engine to move so much that the stern tube started elongating its holes in the plywood bulkhead it was bolted to. I then made a "Halyard marine type" intermediate shaft using two Centaflex couplings and it made things MUCH better in terms of vibration but the noise was still the same.