#1 2019-12-30 09:58:41

Marc_Langbroek
Member
From: Den Helder, Netherlands
Registered: 2019-03-04
Posts: 4

Replacing rudder bearing bushes.

Ls,

As I am in the process of replacing the bearing bushes of the rudder hinges for my Frances 26 "Grace Darling"  I am facing some challenges that might be solved easily with the help of some local expert knowledge. The members forum I hope is the place.

Matter is that for replacing the bronze bushes the whole bearing holder has to be removed, because the trajectory of the bush is in the way of the fasteners of the unit. The top and middle one are no problem, these are bolted thru the stern post, easily reached from within. The real interesting one is the bottom bearing holder. This one is fastened with two nyloc nuts on two threaded ends, who somehow are attached in the lower stern post, lowest corner under the propeller shaft bearing. A corner hard to reach. After removal it showed that from one of the two threaded ends the thread was beyond repair, i.e. useless. To make a reliable construction again, I'll have to replace the damaged end.

Question is: How are the two lower threaded ends fastened in the stern post? I tried to upload a picture in this topic, seems not to work.

Any suggestion is welcome,

Marc Langbroek,

Frances 26 "Grace Darling".

marc.langbroek@gmail.com

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#2 2020-01-01 18:31:52

Hugo_Motamelo
Member
Registered: 2016-12-24
Posts: 3

Re: Replacing rudder bearing bushes.

Mark,

I also would like to check these fastenings. In Boreas K, my Frances 26, they look allright with no leaks but a good check would do no harm.

I took some pictures of the interior of the keel, with poor quality, and I think the bottom gudgeon is fastened like the two others.

If that is the case I think the only way will be to make a very long tool to access the bolts with the help of mirrors, a very strong light and lots of endurance.

If the engine and diesel tank are out maybe things will be simpler.

Sorry for my english!

Happy 2020 with fair winds

Hugo Melo

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#3 2020-01-01 19:13:24

Marc_Langbroek
Member
From: Den Helder, Netherlands
Registered: 2019-03-04
Posts: 4

Re: Replacing rudder bearing bushes.

Hugo,

Thanks for the quick reply. I think we share the same points of view, i.e. the two lower fasteners are almost unreacheable. I tried yesterday with a Bosch endoscope, which gave some insights, but most of the time I was wriggling with the long scope cable trying to comprehend what I was seeing. I ended with a rather obscure view of  the lowest bolthead. The bold was fitted thru a wide washer with two folded sides as to secure it from turning around while being fastened.

So without removing  engine and fueltank I see little possibilities to replace them. I do now use the only protruding centimeter of thread thats workable to fit a threaded bush on it, widen the hole in the gudgeon and  then bolt it all together. Do use grade 416L stainless steel threaded bush to prevent it from rusting on the long term.

Another drastic measurement could be to open up the sternfoot from aside (outside), at the height of the fasteners of the lower gudgeon, and from there replace them. But that involves also some polyester repairs as well.

Success with the challenge,

Marc Langbroek
Grace Darling.

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#4 2020-01-02 23:20:00

Jonathan_Hopper
Member
Registered: 2004-03-23
Posts: 94

Re: Replacing rudder bearing bushes.

'The bolt was fitted thru a wide washer with two folded sides as to secure it from turning around while being fastened'.

I have puzzled these questions over the many years as well.

Is it possible that these washer looking things are some sort of captive nut?

Francesca has had several changes of bushes in the lower gudgeon over the years, usually by the yard.   There have been no nuts appearing in the bilge, and no nuts on the bottom gudgeon bolts (though I do have the washer looking things you describe).   It may well also be that the original bolts (M8?) that have at some point been changed the something bigger (M10?).   My only reason for thinking this is that one of the bent over washers/nuts has been pushed inboard.   I wonder if the 'bent over washers' are actually captive nuts, and also that for the last few years mine has been secured solely by the laminate.   The alternative is that it has always been secured by the laminate!

The laminate at that point is thick, and may well provide enough grip to secure the bottom of the rudder.   I have placed an extra block at the end of the keel so no rope can get between the hull and rudder, so there should be no extraordinary shock loads.   Keeping the laminate dry behind the fitting is useful.

The V800 has a different fitting, and I think if ever the engine was out it would be worth investigating whether sufficient filler could be put in the back of the keel to change to a similar arrangement as it does look easier to service, and perhaps stronger.

There may also be an 'engineering solution' to this - eg something like a riv nut.   However, whilst Francesca supports two bolt which are happily gripping in laminate it is not something that is high on the list.

On the subject of corrosion of the stainless bolt.   Presumably this is crevice corrosion?   The bolts holding the brackets in the rudder suffer from this and I draw them every couple of years to check, but the ones drawn from the laminate looked in good condition last time I had them out (though the previous must have been changed for a reason). Perhaps moisture had got in to the thread?   

Whatever you find with this, or whatever you decide to do, I would be very interested!

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#5 2020-01-03 09:58:38

Marc_Langbroek
Member
From: Den Helder, Netherlands
Registered: 2019-03-04
Posts: 4

Re: Replacing rudder bearing bushes.

Jonathan,

Thanks for the thoughts and the insights. Ill keep you posted on my findings. The bolds securing the brackets on the rudder blade came out rusty, due to the fact that the wrong grade s.s. was used. I.e. A2 , always go for A4.

Marc.

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#6 2020-01-09 22:43:22

Andrew_Gleadle
Member
Registered: 2014-09-23
Posts: 31

Re: Replacing rudder bearing bushes.

Hi Marc

I would also be very interested in your findings as I'm planning on stripping mine next winter (many other jobs this winter).

Like you I took some picture with an Endoscopic Inspection Camera (DropBox link: https://www.dropbox.com/sh/8wofabr8dam0 … 38ua?dl=0). It does appear the nut is held captive with adhesive and a bent washer or form metal. I haven't tried loosening the bolts on the outside but it looks likely the bolts on the inside would stay put.

Regards
Andrew

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