TECHNICAL SUPPORT
Published 2026-05-05
With the characteristics of precise control, ship electric steering gear is increasingly widely used in modern ship automation systems and its control is precise. With its rapid response characteristics, ship electric steering gear is increasingly widely used in modern ship automation systems and its response is rapid. The ship's electric steering gear has precise control and quick response. Its core advantage is that compared with hydraulic steering gear, electric steering gear eliminates the need for oil pumps, pipelines, and complex hydraulic components such as oil tanks. The system structure is greatly simplified, maintenance costs are reduced by about 30%-50%, and there is no risk of hydraulic oil leakage contaminating the bilge. This article, based on the regulatory requirements of the International Maritime Organization (IMO) and the regulatory requirements of major classification societies such as ABS, DNV, and CCS, conducts an objective analysis of the core advantages and disadvantages of ship electric steering gears, and uses practical application cases of common merchant ships, tugs, and fishing vessels as evidence, thereby providing authoritative selection reference for ship designers, maintenance management personnel, and crew members.
1. Compact structure, saving cabin space
It is an electric steering gear directly integrated with an electric motor, reduction gearbox and drive controller, eliminating the original hydraulic pump station and the tens of meters of pipeline system.Taking a 5,000-ton bulk carrier as an example, after converting it to an electric steering gear, the area occupied by the steering gear room can be reduced by about 4 to 6 square meters, which provides greater flexibility for the layout of other equipment.. This advantage is particularly critical for space-constrained tugs, as well as fishing vessels and small work boats.
2. Higher energy efficiency and lower operating costs
Even when the hydraulic steering gear is not steering, the oil pump must always run to maintain the system pressure. When no load is used, the energy consumption accounts for 40% to 60%. The electric steering gear uses the "on-demand work" mode, which means that the electric motor will only start running when the rudder blades are in motion. It is on standby and consumes zero energy when it is not in the steering state.Data obtained from actual navigation shows that the average daily power consumption of electric steering gear on conventional routes is only 25% to 35% of that of hydraulic steering gear of the same specification.. Assuming that the ship sails for 300 days per year and the industrial electricity price is 1.2 yuan per kilowatt hour, a medium-sized cargo ship can save about 18,000 to 25,000 yuan in electricity bills on average per year.
3. Precise control and fast response
Modern AC servo electric steering gear is matched with an absolute encoder, and the rudder angle control accuracy can reach ±0.1°. This accuracy far exceeds the ±0.5° generally possessed by hydraulic steering gear. Among the advantages and disadvantages of ship electric steering gear, such a high-precision feature is especially suitable for DP dynamic positioning ships, ro-ro ships and ferries that require frequent and precise steering. For example, after a car-passenger ferry was replaced with an electric steering gear, the alignment time during berthing was shortened by 40%, thus significantly improving operational efficiency.
4. No risk of leakage, improving cabin safety
For hydraulic steering gear, the most troublesome problem is that hydraulic oil leaks due to aging pipelines or seal failure, which not only causes environmental pollution, but is also more likely to cause fire hazards in the high-temperature environment of the engine room. Electric steering gear completely eliminates the possibility of oil leakage, especially In particular, in compliance with the latest requirements for engine room fire safety under the International Convention for the Safety of Life at Sea (SOLAS), multiple shipowners have reported that after replacing the electric steering gear, the steering gear room has changed from the original working mode of "regular cleaning of oil pollution in accordance with regulations" to a state of "almost no need for cleaning".
5. Easy maintenance, lowering the maintenance technical threshold
It is necessary to regularly check the oil level of the hydraulic steering gear, replace the filter element, clean the oil tank, and test the pressure valve group, which requires high professional skills of the engineer. The maintenance work of the electric steering gear focuses on: checking the gearbox grease every 2,000 hours and measuring the motor insulation resistance every 5,000 hours. No professional hydraulic maintenance tools and knowledge are required, ordinary engineers can do it. After a certain fishing fleet replaced 27 fishing vessels with electric rudders, the annual maintenance time for rudder system failures dropped from an average of 11 days per vessel to 2 days.
1. Single investment cost is high
Usually the initial purchase price is a key factor limiting its widespread application.Under the same specifications, the initial purchase cost of an electric steering gear system is 40% to 80% higher than that of a hydraulic steering gear.. This is mainly due to the fact that electric servos must be equipped with core components such as high-torque servo motors, precision reducers, and high-power drives. For example, the price of an electric steering gear that is not suitable for a 3,000-ton ship is about 120,000 to 180,000 yuan, while a hydraulic steering gear only costs 80,000 to 120,000 yuan.However, based on full life cycle cost calculations, including energy consumption, maintenance, hydraulic oil replacement, etc., electric servos can generally recoup the initial extra price within 2 to 3 years.。
2. Disadvantages of size and weight in high-power applications
For large ships with extremely high rudder torque requirements, such as oil tankers and container ships of more than 100,000 tons, electric steering gear may have disadvantages. As the torque continues to increase, the volume and weight of the motor and driver show a non-linear growth trend. At this time, the power density ratio of the hydraulic steering gear has more advantages. Therefore, the advantages and disadvantages of electric steering gears for ships show different situations on ships of different tonnage: the advantages of electric steering gears for ships below 5,000 tons are extremely significant; however, ships with extremely large tonnage still use hydraulic steering gears as the mainstream.
3. High requirements on power supply quality and stability
The control system of the electric steering gear is quite sensitive to voltage fluctuations and harmonic interference. In the ship power grid, working conditions such as starting up large equipment and switching generators may cause voltage dips (like a drop from 440V to 360V). At this time, ordinary electric steering gear may trigger a protective shutdown. Solutions include: configuring a dedicated power supply circuit with undervoltage delay function, installing a DC support module, or selecting a wide voltage range driver (such as a 300V - 480V adaptive type). However, the above measures will increase the supporting cost by approximately 15%.
4. Electromagnetic noise and impact tolerance
When the electric steering gear is running, the high-frequency switching of the power module will generate electromagnetic noise, which is likely to interfere with ship radio communication equipment. Although qualified products have successfully passed the electromagnetic compatibility (EMC) certification for marine use, when replacing old ships, it is still necessary to evaluate the distance between the installation position of the steering gear and the antenna, radar and other equipment. In addition, under heavy load conditions, the mechanical impact noise of the gear reducer is about 75 to 85 decibels, which is slightly higher than the fluid noise of the hydraulic system, which is 65 to 75 decibels.
A: Not applicable. Small and medium-sized ships, that is, ships under 5,000 tons, tugboats, fishing boats, and yachts are most suitable. Very large merchant ships still need to evaluate the specific rudder torque before making a decision.
A: Yes. The standard configuration of the electric steering gear is dual motor redundancy or a mechanical bypass handle. When one set of motors is damaged, it can be switched to a backup motor, which meets the requirements of SOLAS emergency steering.
A: Generally, no additional operations are required! The electric steering gear base interface is designed according to the International Organization for Standardization, that is, ISO standards. It maintains the same installation dimensions as the hydraulic steering gear with the same torque, so it can be directly replaced.
A: This situation exists. When the temperature is below minus 15 degrees Celsius, a heating belt needs to be installed on the reduction gearbox to start preheating. Otherwise, the viscosity of the lubricating oil may be too high, which may cause overload protection of the motor.
A: From 8 years to 12 years, the life of the motor body is the longest. The main limiting components are the reduction gear, whose design life is 20,000 working hours, and the drive capacitor, which is about 15,000 hours.
A: No, the operation panel is simpler than the hydraulic system. It only includes functions such as start and stop, forward and reverse rotation, and angle display. An ordinary engineer can master it in ten minutes by reading the manual.
A: I’m afraid, the protection level must reach IP56 or above. Otherwise, if there are waves on the deck or condensation in the steering gear compartment, the circuit board will be short-circuited and corroded, so it is very important to check the sealing ring regularly.
Case 1 (Presentation of Advantages): There is a coastal ro-ro passenger ship with a total tonnage of 6,800 and a navigation area of Bohai Bay. The original hydraulic steering gear of the ship leaked about 400 liters of hydraulic oil every year. After replacing it withkpowerAfter the Servo electric steering gear, there has been no leakage for 24 months, and the annual electricity bill has dropped from an average of 36,000 yuan to 11,000 yuan. The captain gave feedback: “In the past, you had to clean the sludge in the steering gear room every time you docked, but now you only need to wipe the dust with a rag when entering the steering gear room.”
Case 2 (verification of shortcomings): A certain offshore trawler with a main engine power of 1200kW tried to modify the high-power electric steering gear with a torque of 45kN·m. However, during the operation, the winching machine was always started frequently, causing the grid voltage to fluctuate, with a fluctuation range of ±22%. In these 6 months, the electric steering gear triggered overvoltage protection alarms as many as 17 times. Finally, the hydraulic system was restored to use, and a UPS stabilized power supply was added.
These two cases objectively confirm the advantages and disadvantages analyzed above. Electric steering gear is not omnipotent. The selection must be based on the specific operating conditions of the ship, as well as the power grid conditions and budget cycle.
Based on the economic and reliability analysis of the entire life cycle, the following hierarchical action recommendations are proposed:
1. Scenarios suitable for immediate use of electric servos:
In terms of ship tonnage, there are such ships, including cargo ships of 5,000 deadweight tons and below. There are also tugboats, fishing boats, engineering boats, and yachts.
The characteristics of the operation are that there is frequent steering, involving ferries, pilot ships, and scientific research vessels, which are the kind of ships that require DP positioning or accurate course maintenance.
Pain points in management include the leakage of hydraulic oil, which has not stopped even after repeated bans, the space in the engine room is in an extremely tight state, and there are certain limits on the level of turbine technicians.
2. Scenarios where it is recommended to carefully evaluate and still choose hydraulic steering gear:
Very large oil tankers, ore ships, and container ships of over 100,000 tons;
What about old ships that are more than 15 years old, and there are difficulties in power grid transformation, and the generator capacity surplus is less than 20%.
In the low temperature conditions of the polar regions or high latitudes, the average annual temperature is below minus 20 degrees Celsius, and preheating and heat preservation conditions cannot be provided.
3. The hybrid solution, that is, the compromise suggestion, is as follows: for a newly built ship, the installation position of the electric steering gear can be reserved at the design stage. In the first phase, a hydraulic steering gear will be selected to control costs. After it is put into operation, after two to three special inspection cycles, the aging of the hydraulic system and the increase in maintenance costs will be used to convert it into an electric steering gear.. By that time, the technology of electric steering gear may be more mature and the price will be lower.
The following is the rewritten content: In summary, the advantages and disadvantages of ship electric steering gear are highly dependent on the specific application scenario. It has the characteristics of no leakage, high energy efficiency and easy maintenance, and represents the development direction of marine steering gear technology. However, it has limitations such as high cost of high torque application and sensitivity to power supply quality, which cannot be ignored. It is recommended that shipowners and design institutes make scientific decisions from the perspective of "calculating the general ledger from the entire life cycle", combined with the actual navigation conditions of the ship and the budget plan. If there is a need for a further technical parameter comparison table or a classification society certification list, you can contact the major electric steering gear manufacturer to obtain the product type approval certificate, also known as TA, and a detailed selection calculation.
Update Time：2026-05-05
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