Three times lighter than steel, aluminium is the material for mobility! It is found in all current means of transport: naval, automotive, rail and aeronautical.
The absence of maintenance, its longevity, its recyclability, its lightness and its extraordinary capacity of resistance to tearing on impact make aluminium the best choice, for more than 50 years, for the construction of sailboat hulls designed to sail around the world.
But if you talk about aluminium in the boating world, you will always find someone to remind you of the dangers of… electrolysis!
But what exactly is electrolysis?
Surprisingly, despite its apparent seriousness, the word electrolysis is not a scientific word that defines a specific phenomenon.
It is in fact an abuse of language that covers two very different corrosion phenomena. These phenomena must first be well understood and then dealt with appropriately to prevent it:
- Galvanic corrosion which is related to the natural differences in potential between different metals in contact with the same electrolyte (seawater), causing the circulation of a very weak electrical current: the corrosion current. It is effectively combated by sacrificial anodes which naturally deliver a protective current against the corrosion current. The cathodic protection they provide can be measured and checked with specific tools.
- Electrolytic corrosion, on the other hand, is caused by the presence of an additional continuous and accidental current: the stray current, which amplifies in one direction or another – and according to its polarity – the effects of the corrosion current. Harmful stray currents from on board or from the dock seek to reach an “earth” and cause accelerated corrosion of the conductive metal at the exit points into the sea!
Early detection and rapid neutralization of possible leakage currents can prevent this phenomenon.
In conclusion, as with all materials, aluminium has its own specificities and precautions for use.
Although electrolysis does not exist from a scientific point of view, corrosion remains a phenomenon that must be treated seriously, especially in the case of stray current corrosion. While the profession experimented with these topics at the beginning of aluminium construction in the 1970s, the industry has been approaching the subject with rigour and professionalism for decades.
In a few weeks, discover how Allures Yachting implements best practices in metal boatbuilding to ensure that our boats remain free from corrosion risks in an article above Corrosion prevention in yacht design and construction. Stay tuned and subscribe to the newsletter.
More information about the safety of an aluminium hull .