Purpose of Shaft Grounding Systems in Marine Engineering
It’s science 101:
Electricity and water don’t mix.
That maxim is no clearer than in marine engineering, where seawater mixed with a propeller’s electrical systems can cause corrosion, loss of efficiency, and system failure.
To fully protect a boat, it is important to electrically ground the boat’s propeller to the hull. Propeller grounding limits corrosion and damage to the propeller shaft, bearings, and gearbox.
Every engine-powered marine vessel must have some type of shaft grounding system installed.
The axis is critical
One of the most critical parts of a marine vessel’s propulsion system is the shaft. Shafts that corrode over time lose efficiency. An overly corroded shaft can cause system failure.
A grounding system is important.
That’s because as electricity passes through the engine to the propeller, it mixes with the water. The combination of the two, called an electrochemical reaction, causes corrosion on the shaft.
The shaft provides thrust to move the boat forward.
Shafts that corrode over time due to electrochemical reactions with seawater lose their effectiveness. They become weaker by transferring power from the boat’s engine to its outer propulsion system.
A grounding system is also required to protect drive motor bearings from electrical damage. Excessive capacitive discharge can cause electrical failure in bearings.
At the same time, uncontrolled corrosion can shorten the life of any boat. This can also cause maintenance problems to occur earlier than otherwise.
How does it work?
The principle behind shaft grounding is quite simple.
In most marine vessels, propellers driven by electric current create charges along exposed sections of the propeller. A grounding system ensures that as little charge as possible escapes. The system is designed to ground all electricity to the hull of the boat.
Grounding prevents free-flowing electrons from doing their damage.
As a result, both the propeller and the engine can run longer and stronger due to less damage. In most cases, each propeller shaft must contain a ground system.
One type of grounding system uses a layer of metal off the shaft. In this way, any electrochemical potential from the seawater will be attracted to the outer shell rather than the axis itself.
Types of grounding vary
The best type of grounding system to use depends on the boat.
There are different options and the owner can choose.
Some factors include the type of engine, the size of the boat, and the composition of the hull. Also, the systems become more complicated depending on the amount of cargo handled. At the same time, the number of propellers and motors a boat has also affects the choice of the system.
Consult a professional
It is not always possible to prevent 100 percent corrosion on or within a marine vessel. But the importance of well earthing systems in marine engineering should not be overlooked.
Talk to a professional for the most up-to-date information on the purpose of grounding systems.
