I read not long ago that the North American research office DARPA is going to launch a project to analyze the practical feasibility of moving ships without making any noise, using the magnetohydrodynamic (MHD drive) technology invented more than 50 years ago, but never brought to practice.
A magnetohydrodynamic system (MHD) is a type of propulsion that uses a magnetic field to generate movement, and is mainly used in ships, which move without the need to use moving parts, such as propellers, turbines, etc...
An MHD system works by generating a magnetic field between an electrical conductor and a magnetic conductor. The electrical conductor heats up and the magnetic conductor cools, creating a flow of electrical current. The flow of electric current generates a magnetic field, which in turn generates a flow of electric current. This cycle is repeated continuously, generating a continuous movement.
MHD systems have a number of advantages over other types of propulsion, such as diesel engines or electric motors. MHD systems are more efficient, quieter and cleaner than diesel engines. They can also run on a variety of energy sources, such as natural gas, oil, and electricity.
However, MHD systems also have some disadvantages. MHD systems are more complex and expensive than other types of propulsion. Its two main drawbacks are that it requires very strong magnetic fields (which means very powerful magnets), and robust electrodes that do not break down on contact with water.
30 years ago, the Japanese used this technology and tested a prototype ship called the Yamato 1, and the results were not as expected, because among other things the ship did not exceed 7 knots, and it consumed a lot of energy. You can see a photo below.
At present, technologies have evolved a lot and powerful magnetic fields are already available that are used in the search for fusion energy, and there are more means to prevent the corrosion of materials.
So it is possible that this DARPA project has some chance of success. And we must not forget that a ship that does not produce noise when sailing is a ship that is more difficult for the enemy to detect, something that is of great interest to the military. Hence the origin of the project.
And we must also consider that many DARPA projects ended up having civil applications, as is the case of the GPS that we have today in our mobiles.
In short, time will tell.
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