Shaft coupler rubber bushing replacement

[Moderator]

I received an email from a friend of Daniel, who is the owner of Nic 38 – hull #21 currently in New Caledonia (Daniel is not yet a member of our forum, but hopefully will join us!)

Daniel needs to replace the rubber bushings in the shaft coupler. He’s hoping someone on this forum can help locate a supplier. Has anyone had to make this same repair? Does anyone know the make of these nifty flexible couplers, and whether the company still exists? Or are they a custom CN part?

My thought is that if the actual rubber bushings are no longer available for purchase, you might try to find some rubber stock and make them – or request a rubber supplier to make them. A good rubber supplier in the US is Canal Rubber, which you can find on the webhere

Alternatively, if the coupler itself is dangerously corroded, you might want to replace the entire coupler. Our mechanic had never seen such a coupler before, so an exact replacement may be hard to find. The flexibility of the couplers is a nice feature, so any replacement with a less flexible design may lead to shaft alignment problems. I can certainly understand why replacing only the rubber bushings is preferable.

I have attached the photos Daniel provided of his coupler.

Marilyn

[michael bennett]

That looks a mess! but nothing a good engineering workshop could not reprduce, I certainly would not suggest fitting new bushes to the old one from what the photograph shows.
He could try here: http://www.asap-supplies.com/marine/flexible-couplings-for-propeller-shafts I have found them a good company to deal with.
If this help is successful we deserve his joining us!

[Moderator]

This is probably too late to help the original requester for information, but George Nauman figured out when he had to replace these parts. Here’s the info he shared with me via email:

George wrote an email to Kevin O’Bryan at Thamesway Marine:

Quote:

I would like to locate a shaft Coupling for my Thamesway Marine Gear box. It is a MK IV 12000. It is a 2:1 reduction model. The shaft is 1 3/8 in diameter. The rubber part of the coupling I have has “Silentloc FC173R” imprinted on the rubber.

Kevin responded with the following info:

Quote:

Prop flex coupling available to suit your application. Part No TM 12307/B3. Price £ 95.00 gbp + carriage.

So – it is possible to get replacement parts for these silentbloc couplers from Thamesway Marine in the UK.

[John Tyler]

Hi Marilyn
I will start a new thread for Cutlass bearing on the site, but your reply here made me think. I am replacing the cutlass bearing [holding the prop shaft just before the actual propellor]. My marine engineer says he has not seen a Cutlass bearing like the one he took out of Aquarius – hull Number 100. Any ideas as to whether there is a standard bearing on the Nic 38s. The engine is a Perkins 4108 as usual.My engineer is going to attempt a replacement asap, but any info gratefully received her [UK].
Cheers
john

[Moderator]

Nic 38’s do not have cutless bearings, they have white metal bearings. We wrote this up on our personal blog when we had to face this problem several years ago – read it here.

You will find other topics in this forum where this was discussed, including some drawings referred here in topic ‘How to remove the cutlass bearing”:

another approach discussed here in “replacing the white metal bearing in the stern tube”.

and some words of advice here in topic about importance of stern tube greaser:

Marilyn

[Author]

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