Aux 1 Unit 9 Q7

A Hydraulic Telemotor System is a control system used on ships, particularly larger ones, to transmit steering commands from the bridge (where the steering wheel or joystick is located) to the steering gear compartment (where the actual machinery that moves the rudder is situated).  

1. HYDRAULIC TELEMOTOR SYSTEM

Key Components:

• Transmitter:
  • Located on the bridge.   1. TELEMOTOR steering gear and its components | PPT – SlideShare www.slideshare.net
  • Consists of a hydraulic cylinder with a piston connected to the steering wheel or joystick.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
  • Movement of the steering wheel displaces the piston, creating hydraulic pressure changes in the system.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• Receiver:
  • Located in the steering gear compartment.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
  • Also consists of a hydraulic cylinder with a piston.
  • Connected to the control mechanism of the steering gear, such as a variable displacement pump in a hydraulic steering system.
• Piping:
  • High-pressure pipes connect the transmitter and receiver, allowing hydraulic fluid to flow between them.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
  • Typically made of corrosion-resistant materials like copper or stainless steel.
• Hydraulic Fluid:
  • A non-compressible fluid, often oil, fills the system to transmit pressure changes.   1. Pascal’s Principle and Hydraulics – NASA www.grc.nasa.gov

Working Principle:

1. Steering Command: The helmsman turns the steering wheel or moves the joystick, causing the piston in the transmitter to move.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
2. Pressure Change: The piston’s movement displaces hydraulic fluid in the transmitter cylinder, creating a pressure difference in the system.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
3. Fluid Transmission: This pressure difference causes fluid to flow through the piping to the receiver cylinder.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
4. Receiver Action: The fluid pressure in the receiver cylinder moves its piston, which is connected to the steering gear’s control mechanism (e.g., the pump control lever).
5. Rudder Movement: The movement of the steering gear’s control mechanism activates the hydraulic system to move the rudder in the desired direction.

Advantages of a Hydraulic Telemotor System:

• Reliable and Robust: Hydraulic systems are known for their reliability and ability to handle large forces, making them suitable for steering large vessels.
• Accurate Transmission: The non-compressible nature of hydraulic fluid ensures accurate transmission of steering commands from the bridge to the steering gear.
• Simple and Effective: The system is relatively simple in design and operation, requiring minimal maintenance.
• Safety: It can be designed with redundancy and fail-safe features to ensure continued steering control in case of a component failure.

Disadvantages:

• Potential for Leaks: Hydraulic systems can develop leaks, which can lead to fluid loss and potential environmental contamination.   1. Know About Hydraulic Leaks: Causes, Detection, and Solutions – Harvard Filtration www.harvardfiltration.com
• Temperature Sensitivity: The hydraulic fluid’s viscosity can change with temperature, potentially affecting system performance.   1. The Role of Temperature Control in Hydraulic Oil Reliability precisionlubrication.com
• Maintenance: Regular maintenance is required to prevent leaks, contamination, and ensure proper operation.

Modern Applications:

• Backup System: On modern ships, the hydraulic telemotor often serves as a backup system to the primary electronic or autopilot steering systems.
• Smaller Vessels: It might still be the primary steering system on smaller vessels or those with less complex control systems.

In conclusion, the hydraulic telemotor system is a reliable and time-tested method for transmitting steering commands on marine vessels. While being replaced by more advanced electronic systems on many modern ships, it remains an essential backup or primary steering control method in various applications.

Core Principle:

• It’s a hydraulic-based remote control system that transmits steering commands from the bridge (where the steering wheel/joystick is) to the steering gear compartment (where the rudder actuation mechanism is).   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• It relies on the incompressibility of hydraulic fluid to transfer motion and force accurately over distances.

Key Components:

1. Transmitter Unit (on the bridge):

• Cylinder: Contains two opposing hydraulic cylinders (rams) and a piston assembly.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• Steering Wheel/Joystick: Connected to the piston assembly via a rack and pinion or other mechanical linkage.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• Spring-Loaded Return: Springs connected to the piston assembly help return it to the neutral (midship) position when the wheel is released.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com

2. Receiver Unit (in the steering gear compartment):

• Cylinder: Similar to the transmitter, it has two opposing cylinders and a piston assembly.
• Hunting Gear Connection: The piston assembly’s movement is mechanically linked to the steering gear’s control mechanism (e.g., the control lever of a variable displacement pump).   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• Springs: Springs help return the receiver piston to neutral, mirroring the transmitter’s position.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com

3. Piping:

• Connecting Lines: High-pressure hydraulic pipes connect the two cylinders of the transmitter to the corresponding cylinders in the receiver.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• Filler/Expansion Tank: A small tank allows for fluid expansion/contraction due to temperature changes and provides a makeup source for minor leaks.

4. Hydraulic Fluid:

• Filling the System: The entire system is filled with a suitable hydraulic fluid (mineral oil is common).

Operational Sequence:

1. Steering Wheel/Joystick Movement:
   • The helmsman turns the wheel or moves the joystick.
   • This motion is transmitted to the piston assembly in the transmitter unit.
2. Transmitter Cylinder Action:
   • The piston’s movement displaces hydraulic fluid in one cylinder and creates a vacuum in the other.
   • Fluid is pushed from the pressurized cylinder, through the piping, into the corresponding cylinder in the receiver unit.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
   • The vacuum in the other transmitter cylinder draws fluid from the corresponding receiver cylinder.
3. Receiver Cylinder Action:
   • The incoming fluid pushes the receiver piston, overcoming the spring force.
   • This piston movement is mechanically linked to the steering gear’s control mechanism.
4. Steering Gear Response:
   • The control mechanism adjusts the hydraulic pump or valves, directing fluid flow to the steering rams or other actuators.
   • The rudder moves in the commanded direction.
5. Feedback and Return to Neutral:
   • As the rudder moves, the hunting gear (a feedback mechanism) senses this and gradually returns the receiver piston to neutral.
   • This, in turn, returns the transmitter piston and the steering wheel/joystick to their neutral positions.
   • The system is now ready for the next steering command.

Key Points:

• Closed-Loop System: It’s a closed-loop system where the receiver’s movement influences the transmitter, ensuring they stay synchronized.   1. HYDRAULIC TELEMOTOR SYSTEM alfidelfi.com
• No Direct Mechanical Linkage: There’s no direct mechanical connection between the bridge and steering gear compartment, allowing for flexibility in ship layout.
• Manual Feel: The springs provide some resistance and “feel” to the steering wheel, giving the helmsman feedback on the rudder’s position.
• Simplicity: While it has several components, the basic principle is straightforward, making it a reliable system.

Modern Context:

Smaller Vessels: It might still be the primary steering control system on smaller vessels.

Backup System: On modern ships with advanced electronic or autopilot steering, the hydraulic telemotor often serves as a backup in case of primary system failure.