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Rudder bearing material suggestion (DIY), for spade rudder


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Its probably boring, but as my haulout is approaching I try to get everything ready by then. The next one is the rudder bearing material. I have access to engineering workshop and various machinery and I'm capable to make things, I would prefer to make this one as well as I don't think it would be too complicated. However I could use some help to find the suitable stuff for the job. About 8 years ago someone mentioned Vesconite on this forum as a good one, which is probably right but I couldn't find supplier for it. So if someone have any suggestion, I would much appreciate that.

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Feck yes. I got some for my beast and nearly had to sell one of the kids.

 

It machines well but do it very carefully. Not the biggest fan of heat so when I drilled a big hole I had lots of water running over it to keep the heat down. Too hot and it melts...too hot is not that hot. 

I've got the "bushing" type, so I don't have to drill it, however I have to be careful with the speed. Too expensive to screw it up. A few more thing to be sorted beforehand , so I'm better to get into it.

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We can recommend getting the old tube drilled out and replaced with a new pre made tube with Jefa bearings installed by Mike Pearce Boatbuilders Phone 09 444 7510

 

Mike did a great job on the retrofit on our Y88 and now we have "fingertip control" on a fully loaded reach. 

 

Well not quite fingertip (it is an 88 and they like to be loaded) but the difference between old and new is huge and it might not cost as much as you think.

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Agree with war machine

I ordered a complete tube with straight non self aligning rollers from Jeffa

Landed here 14 days and way cheaper then bushes... This was a 200mm tube 800 long

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Thanks WM apart from I'm based in Lyttelton and would be some logistic difficulty, I wasn't planned improvement in this magnitude. I'm sure the difference would be great, I stick with the plan for now. I was looking Jefa's system earlier and I agree, they offer probably the best rudder bearing solution at the moment.

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Using Vesconite as a cutlass bearing, not happy. Was installed Nov last year and hauled out in May and now some play, not bad but the 1" shaft can be moved. Was told its normal to have some initial wear!? I wouldn't have expected that much? I thought initially that not enough water was getting through it to keep it cool as it was a little difficult burping the gland. It will be interesting to see how much more wear there is after another summer.

Bob who some will know who makes and sells anodes in 1/2 Moon Bay, suggested sleaving our rudder shaft with a split lenght of SS tube to take up the 1mm play and even gave us a lenght of tube to do it. Despite the knockers, its still good as 4 years later. No wear at all on the rudder shaft or stern tube. Had to burr one end over to stop it from slowly sliding up. Will post a pic later.

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I use vesconite for both prop and rudder...

Held tight with loctite (they make a specific version for this application )

Have installed on lots of boats with no problem.

Is very expensive but including machining works out similar to bronze and other solutions.

Online bearing calculator is helpful.

You can try getting straight from South Africa.

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Vesconite MUST have play..see bearing calculator..the shaft does not sit tight or it will generate heat. It must have water grooves. You need to machine it to their specifications not to bronze or other materials

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Vesconite MUST have play..see bearing calculator..the shaft does not sit tight or it will generate heat. It must have water grooves. You need to machine it to their specifications not to bronze or other materials

Thanks IB, didn't know that. A local engineer did the job for us, there were groves in it for cooling and when he had finished the shaft turned easily with no play whatsoever so was surprised when only after 6 months the shaft now moves slightly in it so it has to have worn slightly. He thought we should fit small scoups on the side of the shaft log to get water into the prop shaft tube, others said enough should get past bearing to do that as we don't go fast enough to need it. Oh well, will see next year when hauling out for winter?

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Hi CH, generally as long as the groove size is as specified, then there is no problem with enough water. 

Faster vessels (power boast) do need assisted water circulation. 

If installed with a standard stuffing box (that by virtue drips water when under way under power) enough water will be present.

If installed with a PSS type dripless seal or similar, then usually a tube / pipe at the seal is installed that prevents an airlock from happening. If installed with a volvo type seal (a lipseal boot) then attention to burping the air from the seal  at relaunch is mandatory  (both for the seal and the vesconite)   and occasionally checking that there is no air later a good idea.

In high speed applications either dedicated scoops or a take off from the engines raw water pressure side is used.

This is the bearing calculator page.  https://www.vesconite.com/design-a-bearing-calculator/

I have no connections with vesconite and like all things marine, vesconite has pro and cons.

Your engine alignment, shaft straightness and bearing surface, as well as prop dynamic balance can make a big difference to bearing life span.

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Figured the breather on the pss should be burped on launch which it was. Water seemed to flow dead easy so the groves in the cutlass were working but never thought of running a feed back through the pss from the raw water cooling. Would that over pressurise the pss!!?

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