All You Need to Know About Anodes for Boats

The anode is one of any boat’s smallest and most fundamental components. But without it, any vessel can be ruined in a very short time by the corrosion of the metal pieces that remain in contact with water engines, for instance. To prevent this from happening, it – the anode – is corroded, thus saving much more expensive and sophisticated components. This is the function of the anode: to erode in the place of others. That is, it exists to be sacrificed, made a nautical piranha. Hence its official name: sacrificial anode.

Basically, an anode is nothing more than a solid block of metal, which, when attached to any submerged metal part of the boat, plays the role of being destroyed in its place. This happens thanks to a phenomenon called electrolysis, or the electric current generated by the union of two submerged metals that of the anode with any other, of the boat, which will corrode the one of greater electro-negativity – in this case, the anode. But for this to happen, there are other peculiarities that must be respected when choosing boat zinc.

Tips About Anodes

  • The best material for the anode is zinc or zinc alloy with magnesium and aluminum, for use at sea. Already in boats that are in fresh water, the best raw material is the magnesium alloy.
  • The anode must not be painted at all, because it completely takes away its capacity to be corroded.
  • Also for the same reason, the anode should not be applied on painted parts. It is necessary to ensure the contact of it directly with a metal.
  • The best locations for anode installation are those with little water resistance, such as inside the engine exhaust or at the outboard base.
  • Any anode must be replaced by another one when corrosion reaches 50% of its size. Because, from there, it will corrode even faster.
  • You can’t exactly calculate an anode’s life span because it depends on how long it stays in the water that is, the more time you submerge, the faster your process of corrosion. It must, therefore, be checked every six months and exchanged for every full year on average. Whenever your boat is out of the water, take the time to see the anode’s condition and place a brush or steel wool in it to remove the deteriorated surface layer. Be sure to require replacement of anode for all engine overhauls. Or, let it be clean at least.
  • Ideally, the anode should be screwed or welded to some metal part of the propulsion, e., shaft, rudder, tail, flap or propeller.
  • Using more anodes than indicated may have the opposite effect. Many metals will cause the mass of the anodes to become harder and will disrupt corrosion. Which, after all, is the goal of this curious but fundamental metal pecker.
Jeffrey Roberts

Emily Roberts: Emily, a former corporate lawyer, demystifies the world of law with clear explanations of legal principles, case analyses, and insights into the legal profession. Her blog is a valuable resource for law students, legal professionals, and anyone interested in law.