Operation and maintenance of navigational equipment

General

It is stressed that it is vitally important that watchkeeping officers are completely familiar with all navigational equipment on board. Navigational equipment should be checked by the officer of the watch to ensure that it is fully operational. Defects should be recorded and brought to the attention of the master. It is of prime importance that bridge watchkeeping officers acquaint themselves with the contents of operating manuals for equipment, particularly with regard to the setting up of controls and the procedure to be followed in the event of a fault.

The master should ensure that regular maintenance of all navigational equipment is carried out in accordance with manufacturers’ instruction manuals. The upkeep and maintenance of individual items of navigational equipment should be the responsibility of a nominated officer, and their operational status should be recorded.

Radar and Automatic Radar Plotting Aids (ARPA)

The master should ensure that at least one radar is available for use by the officer of the watch:

— as an instrument for fixing and monitoring positions;

— as an aid for assessing the risk of collision;

— for practising plotting, parallel indexing, etc.

The radar should be switched on in sufficient time before it is required in order to establish that it is operating correctly and to adjust it to obtain optimum performance.

If weather conditions are such that visibility may deteriorate, the ship’s radar should be operating or at standby. In reduced visibility the radar should be operating continuously and the display should be observed as frequently as the prevailing circumstances require.

The life and operating efficiency of radar sets are affected less by continuous operation than by frequent switching on and off. Therefore in periods of reduced visibility it is better to keep the radar operating or at standby. It two sets are fitted, one should be operating at all times.

The performance of the radar equipment should be checked before sailing and at least once every four hours while radar watch is being maintained. Where fitted, a performance monitor should be used for this purpose.

Whenever the ship’s radar is switched on and at the commencement of each watch if the radar is in operation, the trace should be checked — and if necessary adjusted — to ensure that it is rotating about the centre of the display. At the same time the alignment of the heading marker should be checked as shown in the operating manual.

When using radar for fixing or monitoring the ship’s position the following should be checked:

— the radar’s overall performance;

— the identity of the fixed objects observed;

— gyro error and the accuracy of the heading marker;

— the accuracy of the variable range marker, bearing cursor and fixed range rings;

— on true motion, that the display is correctly ground stabilised.

When operating ARPA, the use of audible operational warning signals to denote that a target has closed to a particular range, or that it is transiting a selected guard zone, does not relieve the master or the officer of the watch of the duty to maintain a proper lookout by all available means. When the ARPA is operating in an automatic acquisition mode, such warning devices should be used with caution, especially when in the vicinity of inconspicuous radar targets. Users should familiarise themselves with the effect of errors on the automatic tracking of targets as described in the ARPA operating manual.

When reduced visibility is encountered or expected, a radar plot should be promptly established. A reduction of speed may allow more time for plotting. The high standard of proficiency necessary for the use of radar in reduced visibility will not be achieved unless regular anti-collision and plotting practice is carried out. The master should ensure that all officers of the watch practice radar plotting regularly in clear weather, particularly when approaching coastal waters after a long ocean passage.

Steering Gear and Automatic Pilot

The officer of the watch should comply with the requirements for the operation and testing of the steering gear and the automatic pilot contained in SOLAS 1974 Chapter V, Regulations 19, 19-1 and 19-2. Guidance on these requirements is contained in Annex 3.

All methods of changeover to alternative means of steering should be displayed prominently on the bridge and be demonstrated and exercised.

The off-course alarm, when fitted, should be adjusted to suit the prevailing weather conditions. The alarm should be in use at all times when under automatic steering. If the alarm becomes unserviceable the master should be informed immediately. The use of an alarm does not in any way relieve the officer of the watch from frequently checking the course being steered.

2. Answer the following questions

1. Why is it vitally important that watchkeeping officers are completely familiar with all navigational equipment on board?

2. What should the master ensure in respect of navigational equipment?

3. What are the main functions of the radar?

4. Where should all methods of changeover to alternative means of steering be displayed?

3. How can you explain notion “clear weather practice”? What can you add to the following idea?