Introduction
Electric propulsion in the marine sector represents a technological revolution that promises not only to reduce carbon footprints, but also to significantly enhance the sailing experience thanks to several advantages: one, high torque, two, comfort, three, ease of maintenance.
The high torque advantage of electric motors.
This high torque offers significant benefits. Let's start with a quick explanation of how an electric motor works.
How an electric motor works :
An electric motor works through the interaction of magnetic fields. When an electric current flows through the coils of the stator (the stationary part of the motor), it creates a magnetic field that interacts with the magnetic field of the rotor (the moving part). This interaction generates a rotational force, or torque.
Couple definition:
Torque is a force that rotates an object around a point or axis. It is measured in Newton-meters (Nm) and represents the capacity of a motor or tool to exert a rotational movement.
For example, screw in a bolt :
Imagine you have to screw in a bolt. You have a ratchet wrench: the longer the wrench, the greater the lever arm and the easier it is to screw. The torque represents the force applied to the lever arm, and the greater the torque, the greater the strength.
Instant Couple
Unlike internal combustion engines (ICEs), which have to rev up to reach their maximum torque, an electric motor can deliver its maximum torque right from the start. This is due to the very nature of electromagnetism: torque is proportional to the current applied and the strength of the magnetic field, and these parameters can be maximized right from the start.
What are the advantages of high starting torque?
- Fast acceleration and responsiveness: With high torque from start-up, electric boats can accelerate quickly, offering superior responsiveness when maneuvering. This is particularly advantageous in harbor areas or in demanding sailing conditions, especially in heavy seas.
- Energy efficiency: High torque allows you to increase the size of the propeller or change it for a more efficient one. This translates into greater efficiency and increased range for the same battery charge.
Silence is golden
An electric, and therefore magnetic, motor is inherently quieter than an internal combustion engine, in which thousands of explosions occur every minute. As a result, the boat is completely silent. The question may arise as to the presence on board of a thermal generator, which could be a bit of a spoilsport. However, the generator is enclosed in a soundproof hull, which in turn is housed in a soundproof bunker, making it a minimal and above all occasional nuisance.
Another interesting aspect of electric drive is its size. Unthinkable with internal combustion engines, electric propulsion fits into the bottom of the hull, providing substantial space savings and unprecedented layout possibilities, even with a central shaft motor.
Easy maintenance
The intrinsic characteristics of electric motors give them a major advantage in the boating world: they are extremely easy to maintain.
With electromagnetism, acceleration and speed management are achieved by modulating electrical current, thus eliminating many points of failure. No complex gearboxes, no reversers, no leaking hoses, no oil changes, just a simple check on battery status and connectivity.
Typical assembly of an Andaman Sails unit
Challenges and considerations
Despite these advantages, the adoption of electric motors is not without its challenges:
Autonomy: Battery capacity remains a critical issue.
The range of electric vehicles is always a sensitive issue. Batteries offer a shorter range than a hydrocarbon tank.
However, it is essential to broaden this perspective.
The introduction of electric motors on boats marks a significant innovation: for the first time, propulsion energy can be generated directly on board.
This is particularly relevant for sailboats, where the sail remains the main engine.
Technological advances in solar panels, photovoltaic sails, hydrogeneration and even wind turbines are driving the industry towards wider adoption of electric power.
With today's technology, it is possible, under mild conditions, to achieve energy autonomy without relying on fossil fuels.
Weather not always kind:
However, weather conditions are not always favorable, and limited battery life can pose challenges in critical situations.
It has to be admitted that, for the time being, a back-up system is essential, often in the form of a diesel generator, which leads to hybridization of propulsion.
Nevertheless, this hybrid solution does not negate all the advantages of electric power: the generator is quieter, easier to maintain, and offers better fuel efficiency (in miles per liter). What's more, the use of fossil fuels becomes more marginal.
Alternative solutions are also emerging, ready to be adopted by the general public, such as fuel cells using methanol/water or hydrogen, promising viable energy sources.
Let's hope that the continuing evolution of battery technologies will lead us to an all-electric boating industry.
Conclusion:
Electric motors for sailing represent a significant competitive advantage, offering improved performance, greater energy efficiency, and reduced noise and environmental pollution, and the motor fits in the bottom of the hull.
Although challenges remain, particularly in terms of autonomy and infrastructure, the marine industry is increasingly turning to electric propulsion, promising cleaner, more efficient and more enjoyable navigation. The future of electric propulsion at sea looks not only environmentally friendly, but also technologically promising.
