Clear weather practice

Operating the radar at sea in clear weather will provide an incentive for watchkeepers to practise their radar collision avoidance and navigation skills; for example, radar observations and target vectors can be checked visually, and in safe waters parallel index techniques can be perfected.

Unit 6

1. Read and translate the text

Navigational equipment. Part 2

Gyro and Magnetic Compasses

It is recommended that the gyro compass should be run continuously. Should it stop for any reason, it should be restarted and subsequently checked before use to ensure it has ‘settled’ and is reading correctly.

Latitude and speed corrections should be applied to the gyro compass by a designated officer. Repeaters should be synchronised with the gyro at least once a watch. The gyro alarm should be checked daily. As a safeguard against the gyro and gyro repeaters wandering, frequent checks should be made between the magnetic and gyro compasses. Care should be taken to monitor errors induced by the ship’s manoeuvring as such errors can reach 5 degrees or more. As far as practicable, compass errors should be checked and recorded each watch using either azimuth or transit bearing, or by comparison with the magnetic compass.

All liquid magnetic compasses should be checked weekly for air bubbles. They should be covered at all times when not in use.

Where fitted as a standby system, the magnetic compass control of the automatic pilot should be tested and exercised not less than once a week and in clear visibility.

Chronometers

Where necessary, chronometers should be wound daily at the same time and check with a radio time signal. The chronometer error should be recorded on the ship’s chronometer rate card and the master informed of any unusual change in rate. Where quartz or electronic chronometers are fitted, batteries should be changed at the manufacturer’s recommended intervals and a record kept.

Echo Sounders

The echo sounder should be used, both when making a landfall and in coastal waters, and particularly in areas where charted depths must be treated with caution.

When approaching sounding depths, the echo sounder should be switched on in ample time, and the operator should ensure that a zero mark is recorded. The echo shoulder should be operated on all ranges and scales regularly until a sounding is obtained. Care should be taken to check whether units of soundings on the echo sounder are different from those on the chart in use.

The time of crossing the more important depth contours should be recorded in the deck log, with the distance recorder reading.

Speed/Distance Recorders

The speed/distance recorder should be operated as soon as it is practicable to do so.

Readings of distance through the water should be entered in the deck log at the end of each watch and at times of establishing positions (where these are recorded in the deck log) and when course or speed is altered. Readings should be entered on the chart alongside the ship’s position.

Electronic Position Fixing Aids

Electronic position fixing aids should be employed in conjunction with other available aids to navigation. The officer of the watch should be thoroughly familiar with their use and limitations, including the application of corrections to readings.

The manufacturer’s operating handbook and current navigational warnings should be consulted to ensure that proper corrections are applied.

When entering the area of coverage of a particular aid, the equipment should be set up in accordance with the operating instructions. Thereafter positions should be checked periodically using other fixing methods to ensure that the equipment is operating correctly. Positions obtained when navigating in areas on the limit of coverage of the aid, or where lattice lines are close together and/or at acute angles of intersection, should be treated with caution.

Direction Finders

The calibration table and curves should be verified by frequent observations. Routine check calibrations should be carried out and recorded at intervals of not more than 12 months and whenever a change to ship’s structure and/or rigging is likely to affect the accuracy of DF bearings.

Hydrographic Publications

One officer should be responsible for keeping charts and other nautical publications up-to-date using the latest available Notices to Mariners and hydrographic/navigational radio warnings. A record should be kept of all hydrographic/navigational warnings, together with details of cleared routes and areas still dangerous to shipping from mines or other causes.

Every care should be taken when using charts which have differing scales and different sounding units.

Emergency Navigation Lights and Signal Equipment

The officer of the watch is responsible for ensuring that emergency navigation lights and signalling equipment are in working order and ready for immediate use at all times.

The condition of flags and shapes should be checked at regular intervals.

Sound signalling equipment must be checked daily and maintained in an operational condition. Where roller guides and wires operate the whistle, these should be examined frequently to ensure easy operation. Electric and automatic whistles should be maintained according to manufacturers’ instructions.

Radiotelephone

A continuous listening watch should be maintained at sea on the radiotelephone distress frequency by the use of an approved bridge watch receiver.

The officer of the watch is responsible for maintaining a listening watch, on VHF (Channel 16) when practicable, and for such VHF watches as may be prescribed by local regulations.

Operating a VHF handset can be inconvenient and distracting and for this reason it should be fitted at the conning position where it can be used while facing forward.

VHF messages should be kept as short as possible to avoid causing channel congestion.

Proper discipline in the use of VHF is essential to maintain the value of VHF radiotelephony as the most effective short range ship/ship communication for distress and safety. In order to remind the VHF user of the need to keep to the proper procedures on VHF Channel 16, a notice should be displayed at or near the VHF equipment on the bridge.

Ship Radio Reporting Systems and Requirements

Ship-reporting systems and reporting requirements have been established to provide, gather or exchange information for many purposes such as search and rescue, vessel traffic movement and ship defects, including deficiencies which could adversely affect navigation or give rise to marine pollution. Normally such reports will be made by radiotelegraphy or radiotelephony and will be free of communication charge to the ship.

Full details of ship reporting schemes and reporting requirements are to found in appropriate hydrographic publications (Lists of Radio Signals, Passage Planning Guides, Notices to Mariners etc.).

2. Answer the following questions

1. Why is it recommended that the gyro compass should be run continuously?

2. Whom should latitude and speed corrections be applied to the gyro compass by?

3. How often should repeaters be synchronised with the gyro?

4. How often should chronometers be wound?

5. In what cases should the echo sounder be used?

6. At what intervals should routine check calibrations for direction finders be carried out and recorded?

3. How can you explain the definition “good radar practice”?

What can be added to the following description?