Taking Over Navigational Watch at Night
1. Go to the chart room about 15 minutes early
2. Inspect the chart,
• The course steered, the set and rate of current experienced, and the course and speed made good (ship's movement over ground) during the previous hour.
• The courses to steer during the watch. Courses must be actually verified, not meroly inspected.
• Anticipated times and positions for alterations of course.
• Expected under-keel clearances (charted depths plus height of tide above chart datum minus the draft of the ship).
• Distances to pass off dangers.
• Characteristics of lights, their rising/dipping distances and the estimated times of such occurrences.
• The traffic separation scheme in that locaity.
• Any other relevant information.
3. Read, understand and sign the Master's Bridge Order Book.
4. Read and sign weather analysis/forecast, if any.
5. Inspect the compass error book (also called azimuth book) and see if:
• The error has been checked during the last watch.
• The error obtained is being applied.
6. Go to the wheelhouse at loast five minutes before time and get eyes accustomed to the dark. Meanwhile carry out points 7 to 12.
7. Inspect tachometer (engine RPM).
8. Inspect navigation light sentinel.
9. Inspect the smoke detector (dry cargo ships only).
10. Inspect the course recorder.
11. Ensure that the VHF is on and switched to Channel 16.
12. See whether on autopilot or hand steering. If on auto, check settings thereon.
13. See what course is actualy being steered (temporary alterations may have been made for traffic, set of current, etc).
14.identify any shore lights that may be in sight.
15. Understand the movement of all traffic in sight, consulting the outgoing duty officer if necessary.
16.If radar is on, get familiar with the picture
17. Look overside, using the daylight-signalling lamp if necessary, to ensure that there is no trace of oil pollution around the ship.
18. Receive true course, gyro course and compass course from outgoing officer and repeat them.
19. Must be in full charge of the watch at the scheduled time - when 8 beils are struck (the practice of striking half-hourly bells during the watch has gradually died out in many companies).
20. The officer being relieved should be satisfied that the relieving officer appears to be fit in all respects to take over and keep the watch. If not, he should inform the Master (or the Chief Officer if the Master is ashore) and remain on watch until suitable relief is arranged.
Soon after taking over watch:
21.Compare compasses.
22. Check soundings by echo sounder.
23. Ensure that the lookoutman is alert.
24. Check that the position, as plotted by the outgoing officer, is correct.
25. Discuss with the outgoing officer regarding any important, unusual or interesting events thit may nave occurred during his watch - concerning ship. ship's staff, meteorological phenomena, VHF or satellite communications with other ships, passing ships of own company or any unusual craft, etc.
26. Ask the outgoing officer whether any verbal instructions have been left by the Master or the Chief Officer - hold ventilation, calling out of crew, changing over of FW tank in use, etc.
27. Read the log entries made by the outgoing officer before he leaves the bridge. If necessary, ask for any clarifications or bring any obvious omi ssions/ errors to his notice.
28. The ship s draft should be prominently displayed on the bridge for quick reference by the OOW. The Chief Officer should update this whenever there is any significant change so that the OOW is aware of the under-keel clearance at all times.
29. Some makes of gyrocompasses require the ship's iatitude and speed to be fed in to offset gym error. In such cases, this must be done by the Eiecond Officer once a day, or earlier if there is any significant change. The Master should be in ormed as and when this is done. The Second Officer should make an entry in the Bridge Not abook,each time, stating the date and time of entry and the values of latitude and speed fed in.
• Now let's see "How to Entries in the Logbook":
Entries in the logbook must be made only after the watch is over and the officer making them has been fully relieved by another officer. The OOW may make notes in the Bridge Notebook, from time to time, to help him to write the logbook later on after handing over the watch.
• Generai round of the ship:
Soon after handing over watch, the officer relieved should make a general round of the ship and ensure that:
1. Fire safety is maintained.
2. There are no apparent (visible) signs of flooding of the ship.
3. There is nothing unusual visible anywhere - such leaking hydraulic connections, unsecured doors, etc.
4. There are no loose/unsecured articles in the smoke room/lounge, pantry, etc.
5. The officer must then inform the bridge "Fire and safe.y inspection carried out. The OOW (officer currently on navigational watch) would then make an appropriate entry in the Bridge Notebook in order to remind him to make this entry in the Logbook later on, after he has been relieved at the end of his watch. lines, loose electrical
In addition, there are special procedures to be followed depending on the type of cargo ship.Let us now talk about the Navigational Watch of several such ships.
On General cargo Ships:
Inspection of deck cargo lashings:
In good weather: Lashings of deck cargo would be checked, once a day, by the cadets and/or crew under the general supervision of the Chief Officer. Tightening may be necessary as the lashings tend to stretch a bit, There should be sufficient scope left in the tumbuckles for this purpose.
In bad weather: Lashings of deck cargo must be checked at the end of each navigational watch. The officer and the lookoutman, who just finished their spell of duty on the bridge, should carry out this duty. They would have plenty of time to do this thoroughly and, if any lashings need major attention, they can call out some more members of the crew and wait until the faults have been rectified to the satisfaction of the officer. The officer must then report to the bridge that deck cargo lashings have been inspected and found satisfactory. The officer currently in charge of the navigational watch should then make a note in the Bridge Notebook to remind him to make the entry Deck cargo lashings inspected and found satisfactory' in the log book after he has been relieved at the end of his watch.
On Oil tankers:
The reading of the pressure gauge on the Bridge, denoting the IG pressure in the tanks, should be recorded every hour. Any undue variation should be brought to the notice of the Master/Chief Officer.
During the day:
The oil in the tanks would expand due to warming up of the decks and hull plating:
1. The IG pressure would then increase.
2. At 800 mm WG, the HP alarm would sound in the wheelhouse and in the CCR.
3. At 1400 mm WG, the PVV would breathe outwards.
4. At 2100 mm WG, the PVB would blow outwards.
However, the oow should take action when the HP alarm is heard and not wait for the PVV to act. He should inform the Chief Officer who would arrange to partially open the mastriser valve until the pressure falls to just below 800 mm WG. The HP alarm would then become silent.
During the night :
The oil in the tanks would contract due to cooling down of the decks and huli plating
1. The IG pressure would then decrease.
2. At 200 mm WG, the LP alarm would sound in the wheelhouse and in the CCR.
3. At 100 mm WG, the VLP alarm would sound in the wheelhouse and in the CCR.
4. At -350 mm WG, the PVV would breathe inwards, allowing air to enter the tank. This is dangerous as entry of fresh air would render the atmosphere in the tank to come within the fiammabie range.
5. At -700 mm WG, the PVB would blow inwards.
However, the OOW should take action when the LP alarm is heard and act before the VLP alarm sounds. He should inform the EOW who would arrange to top up the IG by starting either.
• The IG Topping up Generator, if provided on board or
• The IG plant itself.
In actual practice
When the diurnal range of atmospheric temperature is expected to be iarge, some ships take steps to ensure that the necessity to top up IG at night/early morning should not arise. During the day, when the HP alarm sounds, the audible signal of the HP alarm is acknowledged (silenced) but the pressure, closely monitored, is allowed to rise up to about 1300 mm WG or so (the PVV breathes out at 1400 mm WG). If the pressure exceeds 1300 mm WG, the pressure is released by partially opening the mastriser valve. The IG pressure is thus maintained between 1200 and 1300 mm WG. During the night, the LP alarm may not sound (pressure in the tanks may not fall to 200 mm WG). The necessity to start the IG generator, or the IG plant itself, may not arise.
In UMS (Unmanned Machinery Space) ships, or UMS at night ships, the EOW usually makes an assessment at about 2200 hours or so and, if necessary, tops up the 1G in the tanks then itself so that he is not woken up during the wee hours of the morning for this purpose.
The ship should have a policy regarding this and the Chief Officer should leave written, standing orders for the OOW.
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