centaflex coupling - worth it?

D

deep denial

Well-Known Member
Joined
10 Mar 2006
Messages
517
Location
Southampton
Visit site
Am re-enginging but keeping old propshaft - single engine 38Hp. It has been suggested to me that buying a Centaflex coupling in place of my existing r&d will give significant benefits in terms of vibration etc. Not everyone agrees. does anyone have any views on this?
 
deep denial said:
Am re-enginging but keeping old propshaft - single engine 38Hp. It has been suggested to me that buying a Centaflex coupling in place of my existing r&d will give significant benefits in terms of vibration etc. Not everyone agrees. does anyone have any views on this?
Click to expand...

I fitted one, primarily because I wanted to fit softer engine mounts to isolate my steel hull from the Perkins 4108 and the Centaflex I felt, allowed for greater movement and isolation.

Both made a big difference however there appeared to be a design flaw in the coupling for 1.5" shafts in that the clamping holes were very close to the outer edge and the tapped holes split the steel when tightened. The coupling was replaced by ASAP Supplies without quibble and so far has been trouble free. The versions for thinner shafts would not suffer from this issue, if indeed it is an issue and was not due to the engineer overtightening the clamping bolts. (If you fit one - use the specified tightening torque)
 
Depends on your engine arrangement to a considerable extent IMO. My previous boat, with a 2 cyl Yanmar transmitted a lot of vibration to the hull via the shaft, despite an R&D coupling. The distance between the gearbox coupling and the stern tube was quite short. This, combined with the bouncy engine caused this effect, with the stern tube stuffing box taking quite a lot of hammer it seemed. I fitted an Aquadrive, which brought about a great improvement, could hardly tell that the engine was running, (I jest!!) It still moved around a lot of course, in fact more than before when the shaft restrained it.
My present 3 cyl. Beta is inherently much smoother, also with less flexible mounts, so engine movement is slight. With just an R&D coupling. little vibration is transmitted to the hull via the shaft, and I wouldn't bother with an Aquadrive for vibration reasons.
NB The Aquadrive is basically similar to the Centaflex AGM AFAIK.
 
Last edited:
earlybird said:
NB The Aquadrive is basically similar to the Centaflex AGM AFAIK.
Click to expand...

It is, but I don't think the OP meant a Centaflex AGM, rather the common Centaflex M, which is just a flexible coupling. The Centaflex AGM and the Aquadrive are good solutions to vibration, but require a bit of work to create substantial mounts for them.
 
I fitted a Centaflex coupling in 2001 (M-type, I think it was).

It cut down the vibration and has never given any trouble.

My engine is a BUKH 10hp, single cylinder. The stern gear is the 'old fashioned' rigid type, with white-metalled inboard bearing and a packed gland. The shaft diameter is 1-inch.
 
I fitted on to my last boat. I 'think' it made things better, but I was having problems with the stern gland - no problems after that.

I would recommend replacing the bolts with stainless steel ones - it comes with steel Cd plated and they will rust. The SS ones makes dismantling easier.
 
pvb said:
It is, but I don't think the OP meant a Centaflex AGM, rather the common Centaflex M, which is just a flexible coupling. The Centaflex AGM and the Aquadrive are good solutions to vibration, but require a bit of work to create substantial mounts for them.
Click to expand...

Agreed, my mention to the AGM was perhaps a not-very-clear attempt to indicate that my experience with an Aquadrive was not fully comparable with, say, the Centaflex M series, which really can accommodate only a limited angular misalignment. I suspect that this type of product is only marginally better than the R&D for vibration isolation, and to really benefit from fitting soft engine mounts, then a cardan-shaft design is best able to accommodate both angular and radial misalignment, admittedly at the expense of more complicated fitting.
 
Last edited:
You must log in or register to reply here.

Share this page

Top