Steering Gear System: Pre-Departure Checks, Tests, and Key Components

According to SOLAS Chapter V, Regulation 26, the ship's crew must complete the following checks and tests within 12 hours before departure from port:

Required Checks and Tests:

• Main steering gear: Operate and check for correct function.
• Auxiliary steering gear: Operate and check, except when the gear includes tackle.
• Remote control systems: Test all remote steering gear control systems.
• Bridge controls: Test steering positions on the navigation bridge.
• Emergency power supply: Ensure the emergency power supply operates reliably.
• Rudder angle indicators: Check that these accurately reflect the actual rudder position.
• System power failure alarms: Operate and check alarms for remote control system power failure and steering gear power unit failure.
• Automatic equipment: Test automatic isolating arrangements and any other automatic devices.
• Rudder movement: Move the rudder through its full range, as per steering gear capabilities.
• Visual inspection: Inspect the steering gear and its linkages for condition and leaks.
• Communication check: Test communication between the bridge and the steering gear compartment.

Procedures Involved:

• Physically operate the main and auxiliary steering systems from all control stations, including emergency operation where fitted.
• Test alarm systems by simulating power failures to ensure alarms activate correctly.
• Move the rudder throughout its operational range (port-to-starboard and back) while observing indicators and checking for smooth response.
• Visually inspect all accessible parts for hydraulic leaks, unusual noises, or visible faults.
• Test communication equipment (such as phones or talk-back systems) between the bridge and the steering compartment.
• Check the response to helm orders in both manual and automatic modes, if equipped.
• Ensure instructions and schematics for changing between control systems or power units are clearly displayed on the bridge and in the steering compartment.
• Emergency drills: Although not required before every departure, emergency steering drills must occur at least every three months and be documented.

Documentation Required:

• Logbook Entry: The date, time, and details of all steering gear checks, tests, and drills performed must be recorded in the ship’s official logbook.
• Drill Records: Maintain records of the dates and outcomes of emergency steering drills.
• Instructions Display: Operating instructions and changeover diagrams must be posted on the bridge and in the steering compartment.

The hunting gear is a critical feedback mechanism within the steering gear system.

Construction:

It typically consists of:

• Floating lever: This lever is linked at one end to the telemotor receiver (which receives helm orders from the bridge), at the other end to the hunting lever (which provides rudder position feedback), and in the middle to the pump control lever.
• Control rods and linkages: These mechanically connect the rudder's movement and the helm order to the hydraulic pump control.

Working Principle:

1. Upon receiving a wheel order, the telemotor receiver pushes the floating lever.
2. This action moves the pump control lever away from its neutral position, initiating hydraulic pressure to the appropriate ram or vane.
3. As the rudder turns, the hunting lever (which is attached to the rudder stock) moves correspondingly, feeding back the rudder's position to the floating lever.
4. When the rudder achieves the ordered position, the hunting gear automatically re-centers the pump control lever, stopping the hydraulic flow and holding the rudder steady.
5. This mechanism ensures the rudder stops precisely at the desired angle without overshooting, leading to accurate and responsive steering.

Purpose:

• Servo-control: The hunting gear acts as a vital feedback system, making the steering gear self-correcting and precise.
• Prevents overshoot: It ensures the rudder stops exactly at the commanded angle.
• Operational safety: It maintains reliable control over the rudder position, regardless of sea conditions.

Consequences of Hunting Gear Failure:

• Loss of Feedback: The rudder may overshoot, leading to "hunting" (continuous oscillating movement) or steering instability.
• Poor Positioning: The system becomes unable to accurately reach or hold the rudder at the ordered angle.
• Increased Wear: Excessive, uncontrolled rudder movement increases strain and wear on both mechanical and hydraulic components.
• Possible Loss of Steering: In severe cases, failure can result in a total loss of steering control, potentially leading to collisions or groundings due due to the ship's inability to maintain a steady course.