Cathodic Protection in Yachts
Cathodic Protection in Yachts
If you have two different metals physically or electrically connected and then you immerse them in seawater, they become a battery. Some current flows between the two metals and the electrons that make up that current are supplied by one of the metals giving up bits of itself-in the form of metal ions-to the seawater. This is called galvanic corrosion and can destroy underwater metals. The obvious casualty is the bronze or aluminium propeller on a stainless steel shaft.
In order to counteract galvanic corrosion you need to add a third metal into the circuit, one that gives up its electrons first. This piece of metal we call a sacrificial anode, and usually it is zinc. It cannot be emphasised enough the importance of maintaining the zinc anodes on your boat. When an anode is dead, the metal component it was installed to protect begins to die.
A professional yacht surveyor will check your yacht has cathodic protection.
Factors to bear in mind
The larger the surface area of a zinc anode the more protection, although this does depend on the metal it is protecting. Replace an anode when half gone do not nickel and dime.
Check your anodes at least annually and replace those that are half depleted.
For protection it is CRUCIAL that an anode must be in electrical contact with the metal being protected. Low-resistance, metal-to-metal contact is required so you can either by mounting the zinc directly to the metal being protected or connect the two with a wire.
Ensure that when an anode is mounted directly to the protected metal, e.g bolted to the side of a metal rudder, the surface that the anode is connected to must be bare and bright. Do not paint anodes.
What can go wrong?
Read about Skin fitting failures here
This Westerly Pageant had a nice shiny new anode but someone had removed the connection to the stern gear. The result? Dezincification of the propeller and the need for a replacement. Note the pink appearance? When sounded with a hammer the propeller did not ring like a bell, and when struck on it’s edge with a file a large piece of propeller blade came away.
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Here are some snippets of recent reviews. they can be seen in full on our testimonials page, or on the facebook and google+ links above
The whole process was very easy.
Matt was very helpful during the survey including us in all aspects and his report was well structured and easy to follow and understand. Additionally his help and advice following his report was excellent.
I would not hesitate to use him again. Chris. Reviewed on this site June 2019
“…Communication was good and we arranged to meet whilst the survey was being carried out…. Matt was very good at explaining all aspects of the survey….The result was a very comprehensive and thorough survey report clearly identifying any problems, how to resolve them and the time span in which they should be done.
…… Matts approach, help and advice made it a good experience.
Matts services are highly recommended. Les. Reviewed on facebook June 2019
….very detailed and yet very clear with his report and recommendations……… I would recommend him without any hesitation. A very professional and helpful surveyor. David G. Review on facebook November 2018
I can’t praise Matt highly enough for the survey on my new boat. He was meticulous to a fault, happy to be left to do his thing and was invaluable on the sea trial. The fee was very reasonable ……..Thanks Matt. Peter E. Reviewed on Freeindex July 2017
…..Matt was very thurough and took the time to explain to me the issues and advice me during the survey. I was extremely pleased with his work and would recommend him to anyone looking for a first class surveyor. Sebastian. reviewed on facebook, Feb 2017
Matt provided an extremely professional service …… He was most helpful on the day of the survey, spending time explaining and discussing points identified and recommended fixes to pragmatically resolve……report was delivered the within 48 hours ……presented in a way that was easy to understand and extract key points that needed to be addressed with the Yacht Broker. I have no hesitation highly recommending Marine Surveys UK based upon the services provided. Husron V.P Reviewed on cylex Jan 2018
“Matt provided an excellent survey service ….. very flexible with timings, arrived promptly and conducted a very thorough inspection, taking time to explain key points to me and offer general boating advice. The report came through very quickly and was comprehensive, clear and made sensible recommendations. I would fully recommend Matt. ” Nick Bournemouth, Review Jan 2016
….. ‘Ancasta’ ………. recommended using Matt for our survey. …..Matt was extremely helpful and easy to deal with. I attended for part of the survey, and he took time to talk me over the yacht and gave me a very detailed verbal description on the day. This was followed up naturally by a more detailed written report . Everything was dealt with very promptly , Matt was easy to contact throughout the process , and I would highly recommend his services .
“I was very pleased with the survey that you carried out for me,It was comprehensive and at a fair price ,done when I wanted and it was very useful to be able to discuss you findings with you” Chris Forsyth. Olympic 500C. December 2014
…….. he was very thorough and answered any questions I had. Overall an excellent service without fault or delay so if you are looking for a marine survey I would highly recommend Matt. Terry Goulty. Rinker 232 December 2014
………He made a pre-purchase condition survey to great value for me. He also taught me a lot about this boat model. Knowing the status of the boat we had a nice sailing trip home to Sweden.” Jörgen Haslum December 2014
… A really nice guy, very knowledgeable and helpful. The report was clear and easily understood and all findings were clearly put into perspective for me. Thoroughly recommended! Peter Bristow, Haywards Heath May 2014
Excellent survey at a very reasonable price and the report was received the following morning … Matt was also happy to offer further free advice on the phone several weeks later and I’m sure even years later he’d continue to do so. …. Gary from Fleet. April 2014
…Matt did a great job, supporting me from start to finish and coming up with common sense solutions to potentially tricky problems. I will certainly be instructing Matt for my future surveying needs.Paul Lovejoy, Emsworth Feb 2104
…His inch by inch and nut and bolt complete survey was broken down into easy to understand sections that graded the work to be done using a simple star grading system. ….. He gave me the confidence to make my purchase, undertake the repairs and to have a boat now which has given me many happy hours of sailing. Mark Wood Portsmouth
Our 1984 Sunseeker 25 XPS Portofino required a safety / condition report for insurance purposes. This was carried out very efficiently and without fuss. P. Crowther-Wilton, Banbury 1st January 2014
Matt West was recommended to me …. the service he provides is prompt, reliable helpful and efficient. From initial call to receiving my survey took just a week. I would have no hesitation in recommending Matt” Andrew Campbell
Sent from my iPad December 2013
The previous owner, ….. was very impressed with your level of detail and testing and has kept your details to use your services when he buys his next boat. ….. we are very happy with her and in the knowledge that she has had a very thorough and detailed survey performed on her by a very knowledgeable and professional company. Dave D. December 2013
As a foreigner, having someone local you can trust, acting as your eyes and your ears and helping you to keep you with both feet on the ground, is an investment that’s worth every penny. Joris Van Roy, Belgium December 2013
He went out of his way to be helpful and even accompanied us on the sea trial. He produced an extremely comprehensive survey report and so far 3 months on I have not found a single thing he has missed. He is an accomplished professional with an in depth knowledge of boats and has been an invaluable source of advice. I would have no hesitation in recommending him to you, you would have to go a long way to find anyone better.” Mike S. December 2013
I have used surveyors when buying boats previously and none came up to the standard of service provided by Matt. Peter V. Sea Ray 240 July 2013
A very friendly and exceptionally helpful service, I would definitely recommend them. Rosie T. 43′ Narrow boat June 2013