Troubleshooting
1. Oil Leakages: Oil leakage from the steering gear is one of the most common problems on ships – a result of machinery systems having several moving parts operated by hydraulic oil. Some of the main areas of leakages are cylinder-ram seal in hydraulic ram-type steering gear and seal in the chambers of a rotary vane pump. Any kind of leakage from the steering gear system must be rectified immediately.
2. Difference in the Actual Rudder Angle and Ordered Helm Angle: Another common problem observed in the steering gear system is the difference in the angle given at the helm and the actual rudder angle. This occurs due to wrong or insufficient adjustment of control and repeats back lever. To rectify this problem, the turnbuckle attached to the rod of control and repeat back lever is to be precisely adjusted.
3. Unsatisfactory Steering: The fuel consumption of the ship greatly depends on the efficiency of the steering gear operation. If the steering gear is operating unsatisfactory, it will lead to a delay in the ETA of the ship and increase main engine fuel consumption. A common reason for this problem is the malfunctioning of safety valves or bypass valves in the system. Any problem in the control and repeat back lever will also lead to unsatisfactory steering.
To solve this issue, safety and bypass valve operation are to be checked at regular intervals. If any problem is noted, the same is to be recited at the earliest. For the control and repeat back lever, the turnbuckle attached to the rod of the control and repeat back lever are to be precisely adjusted.
4. Excessive Noise from Steering Gear: Excessive noise and vibrations from the steering gear indicate entrapment of air in the system. Due to air bubbles in the oil, pumps and pipings are subjected to air hammers leading to vibration and heavy noise. Air must be removed from the system using the vent valve provided in the cylinder and pump especially after the system is replenished with new oil. If the valve located in the oil supply tank of the steering gear is throttled or closed, it will again develop air bubbles in the system. Ensure that this valve is always open when the system is in operation.
5. High Oil Temperature: Oil is the operating media in the steering gear system. Any abnormality in the parameters of oil will lead to other operations-related problems in the steering gear. If there is an increase in the oil temperature, it will directly reduce the viscosity of the oil and hamper the steering operation. The most common cause of the increase in oil temperature is the low oil level in the system. Thus, ensure that the low oil level alarm in the tank is working and replenish the oil when required.
6. Rudder Movement is Within or Beyond the Limit: The SOLAS requirement for steering gear says that the system must be capable of putting the rudder over from 35 deg on one side to 35 deg on the other side of the ship at its deepest seagoing draught and running at maximum ahead service speed.
It may sometimes happen that the maximum angle reached by the rudder is less than prescribed or the rudder is overshooting the 35-degree angle mark.
One of the main reasons for this problem is the malfunctioning of the limit switch fitted on the repeat back unit or on the autopilot. Replace the malfunctioned limit switch or adjust the limit switch to the maximum prescribed rudder angle
7. No Steering from Remote Control: There is always a provision of local manoeuvring in the steering gear for an emergency if the remote control operation fails. Some common reasons for the failure to remove controls are :
- Break down of hydraulic pumps: Another hydraulic pump to be started in such cases
- Malfunction of the transfer valve
- Malfunctioning of the hydraulic bypass valve in the pump
- Oil leakage
- The problem with the tele-control system
8. Rudder Angle Transmitter and Tiller Link Failure: On 29 April 2011, Panama registered bulk carrier Dumun grounded while departing the port of Gladstone, Queensland. Prior to the grounding, the ship’s steering appeared to have stopped responding to bridge commands when the linkage between the tiller and rudder angle transmitter detached.
The steering gear continued to operate normally, but the transmitter lost its input signal and, as a result, the bridge-mounted rudder angle indicator stopped working. To avoid such accidents, ensure that the duty officer must take around before every manoeuvring or departure port to check all the linkages in the engine room.
