Flexible Couplings

[Luke]

Has anyone had any experience of fitting a flexible coupling to reduce the engine noise transmitted through hull? If you believe the literature from the likes of Halyard Marine it would appear to make a big difference to noise levels - but I'm reluctant to shell out several hundred pounds if its largely marketing hype!

 

[Trevethan]

reminds me of the joke about the contortionist....

 

[ccscott49]

Englander has a system very similar to halyards, maybe an early type, it is fabulous and makes a huge difference to the hull borne noise. If you can afford it, go for it!

 

[Luke]

Thanks

Any idea on where I can find out about Englander?

 

[Avocet]

I'd be careful about the testimonials. I made up something pretty much like the Halyard shaft (a short intermediate shaft between two "Centaflex" rubber "doughnuts"). It didn't make much difference to the percieved noise level but made a huge difference to the vibration - especially at tickover. I have a nasty little single cylinder diesel. It hops about like a demented thing when idling. At the time I fitted the coupling, I had already fitted some Vetus hydraulic engine mounts and was disappointed with the results. I then realised that it was a bit daft having nice soft engine mounts and a rigid propshaft (which kept knocking out it's stuffing box mounting)! I also had virtually no sound insulation fitted. Depending on what sort of engine you have and what sort of mountings it's on and what level of insulation you already have round the engine bay, I'd say it may or may not make a huge difference. Perceived noise seems to be one of those things that permeates the boat by any means it can and only really becomes controlled once all the measures have been implemented.

 

[vyv_cox]

If you search the archives on Aquadrive you will find my experiences. Probably about March/April.

I have been very disappointed with mine. It was fitted to overcome shaft knocking on stern tube after changing engines to one with softer mountings. It has largely done this but the transmitted engine noise through the Aquadrive is far greater than it prevoiusly was through the engine mountings. My installation was always very quiet, apart from the stern tube knocking. Now it is quite noisy at revs above 2000.

Several other contributors had poor experience with theirs. Since then my son has bought a boat with one and his is very noisy.

Engine bay sound proofing has had a much greater effect on reducing noise but this can't do anything for transmitted vibration.

 

[ccscott49]

I'm in Ibiza with her.