371 - rudder post corrosion

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rudder post corrosion

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 371
Forum Description: 371 Hints and Tips
URL: https://www.myhanse.com/forum_posts.asp?TID=9579
Printed Date: 27 March 2026 at 03:40
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com

Topic: rudder post corrosion

Posted By: BAJJ
Subject: rudder post corrosion
Date Posted: 22 April 2016 at 16:49

Hi All,

I have noticed from the forum that rudder post corrosion can be an issue with the early Hanses, the 311, 341 and 371 and i am guessing the 411. I bought my 371 last year and it came with a brand new jefa rudder as the stock on the old one had totally corroded away.

So I hauled last week to clean and antifoul and there is already signs of corrosion on the new rudder stock, 1 - 2mm pitting in a few areas. Nothing of major concern at the moment but it will become a problem if it persists. I have done some research and there is a lot of information but nothing definitive, so, can anyone advise what they have done that prevents this happening, do I need to fit a galvanic isolator, will a hanging anode work and if so what do I connect it to? etc etc. All advice appreciated.

Thanks

BAJJ

Replies:

Posted By: Yeoman
Date Posted: 22 April 2016 at 17:43

Hi Bajj,

If you have time it is well worth reading this article on rudder materials, electrolysis and corrosion.

LINK- http://www.jefa.com/rudder.htm" rel="nofollow - http://www.jefa.com/rudder.htm - then choose the 4th option down

Kind regards

Phil

-------------
Inspiration Marine Group LTD - UK Importer for Hanse Yachts. Helping owner’s to get the best from their boats.

Posted By: Bitbaltic
Date Posted: 22 April 2016 at 21:42

If the range of reports received over the years on this forum is representative, the quality of materials sourced for rudder stocks on the early Hanses- production of which seems largely to have been outsourced in Poland- was universally poor. The problem is endemic with my boat (the 301) most of which are now 15-20 years old and I know of probably half a dozen boats which have reported problems on this forum and elsewhere.

This 'early rudder issue' is so established that you might expect the surveying community to be aware of it by now? I'd be interested if anybody has had potential rudder problems flagged by a surveyor when buying an older Hanse. That said I have not heard of corrosion problems with a Jefa rudder (until now)!

Posted By: bovine
Date Posted: 22 April 2016 at 23:30

Hi guys
My 430 from 2007 is on the hard for annual maintenance, I check the rudder stock every year and have no problems.
I never ever leave it plugged into shore power when not on board, and have a anode bolted to the hull as close as possible with out fouling rudder movement, wired with a heavy stranded cable to the rudder quadrant on the inside.
Under no circumstances bond this to the negative of the battery's, also switch all battery's off when leaving the boat.
David

Posted By: GrainDeSel
Date Posted: 23 April 2016 at 07:35

Hi all
My boat is H385#139, She is in the water since august 2012. This year I found galvanic corrosion on the rudder!
No ground cable, no shore power, Jefa specifications for fouling are respected. ... See my post I am very desaponted
http://www.myhanse.com/rudder-corrosion-protection_topic9558_post79587.html?KW=#79587
Best regards

-------------
Best regards
Jean-Marie
H385#139 june 2012

Posted By: bovine
Date Posted: 23 April 2016 at 08:19

Hi Graindesel
Have you identified the problem? You need to fit an anode, it is likely your rudder stock is grounded through your auto pilot or compass light.
An anode will solve your problem
David

Posted By: BAJJ
Date Posted: 23 April 2016 at 09:48

Thanks all,

I think the issue may have been that all winter I had the boat connected to shore power to run a dehumidifier, research shows that this can be an issue, a galvanic isolator may solve this and I will look into fitting one before next winter.

In the meantime I have painted the post and the top of the rudder with international trilux (same coating as for the sail drive) as per the instructions on the Jefa website. I also want to fit a hanging anode, I just do not know where to attach it, any ideas?

Again thanks

BAJJ

Posted By: bovine
Date Posted: 23 April 2016 at 18:33

Hi Bajj
The anode needs to be connected to the rudder post ,best to bolt on hull and bond to quodrant.
As for shore power for your dehumidifier make up a lead that plugs in to the pontoon post and just run it into the boat and plug in direct, therefore isolating the boat
David

Posted By: GrainDeSel
Date Posted: 23 April 2016 at 22:54

Hi David
Problem is not identified. Rudder is correcfly insulated from pilote, battery, and other metallic pieces! I am regarding to put an anode screwed on the rudder stock and directly on the sea when we are berthing.
Many thanks and best regards

-------------
Best regards
Jean-Marie
H385#139 june 2012

Posted By: samuel
Date Posted: 24 April 2016 at 08:35

Will the anode not pick up stray current from the other boats, or badly earthed electricity supplies, near you & lead them up the wire & on to your rudder shaft then back down into the water??
In other words will the anode corrode or will it actually do the opposite of what you want & attract stray currents

-------------
Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex

Posted By: BAJJ
Date Posted: 25 April 2016 at 16:12

Hi Guys,

Thanks again. One of my concerns is exactly as you say Samuel and I could end up making the situation worse, hence my post. I thought that someone here would have looked at this as a potential solution. However I have done some more research and found the following info in a few places regarding anodes 'For a zinc anode to provide any protection, it must be in electrical contact with the metal being protected. The conductivity of the water is not adequate. We need low-resistance, metal-to-metal contact--either by mounting the zinc directly to the metal being protected or by connecting the two with a wire. A hanging anode can provide protection if it is connected by a wire to the metal being protected' from http://www.boatus.com/boattech/casey/sacrificial-zincs.asp, and other sources. With this in mind I will look at a hanging anode connected to the rudder and will monitor its effectiveness.

Thanks

BAJJ rudder

Posted By: Zwerver
Date Posted: 27 April 2016 at 14:31

Has anyone considered to replace the aluminum containing rudder for one with a stainless steel rudder post?
Would it be possible to use same bearings etc.
Regards
Wim