Duties of Officer on Watch (OOW) After Taking Over Watch

A deck officer assigned with the duties of watch keeping and navigation on a ship’s bridge is known as the officer on watch (OOW). While keeping a watch on the bridge he is the representative of the ship’s master and has the total responsibility of safe and smooth navigation of the ship.

Officer on Watch (OOW) is also in charge of the bridge team, which is there to support him in the navigation process. He is also responsible to ensure that the ship complies with COLREGS and all the orders of the master are followed with utmost safety under all conditions. The three main duties of an officer on watch (OOW) can very broadly, for the sake of understanding only, can be classified under:

  • Navigation
  • Watch keeping
  • GMDSS radio watch keeping

Officer on Watch

A list of main duties of an officer on watch (OOW) is provided below. However, this is not an exhaustive list and the duties may change according to the requirements. The following constitutes the aspects required to be checked and monitored after having taken over the watch (to know more about taking over the watch, read https://www.marineinsight.com/marine-navigation/8-important-points-for-efficiently-taking-over-a-bridge-navigational-watch/) Therefore, soon after taking over the watch:

  1. Compare the compasses: This is done in order to have a precise estimate window within which the compass errors can affect the course to be steered and thereafter, made good. In case a gyro fails, the OOW must be aware of the extent to which the the error of the magnetic might affect the course being followed/to be followed. Also, a comparison of the repeaters is essential to know if the repeaters are aligned with the master gyro and showing the correct reading which is needed when reading from the bridge or when calculating the compass error using the Azimuth
  2. Check soundings by the echo sounder. Needless to say, the UKC and the depth of water at any point is imperative to the safe navigation of the ship. While a record is made of the depth if need be and if instructed by the Master to do so, it is also necessary for the OOW to account for the errors of the echo sounder to ensure that the correct reading is obtained (basically, avoiding under or over reading of the depth). This is especially crucial when in shallow waters as failure to understand the actual depth can have devastating effects such as grounding of the vessel.
  3. Ensure that the lookout is alert: Not just the lookout but also the helmsman should be alert at all times. Rule 5 of COLREGS puts special emphasis on lookout and states that “Every vessel shall at all times maintain a proper lookout by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.” Again , the importance of this can be best explained when considering the vessel in restricted visibility (RUle 19 of COLREGS) wherein the role of the lookout man is paramount.
  4. Check the position: The OOW must check the position plotted by the outgoing OOW and not depend entirely on the displayed information on the chart. While this is not to question the outgoing OOW, it is necessary to do so for personal convincing and rechecking it to ensure that there has been no errors. The precious positions affect the future position and therefore, in order to maintain maximum accuracy of the plot, this must be done.
  5. Discussing with the outgoing OOW: Navigation of the vessel is extremely dynamic and therefore all conditions at any given time affect the ship in a certain way and also helps us to ascertain the trend with regard to the movement of the ship and the surroundings. The current OOW must discuss with the outgoing OOW if there has been any unusual activity, any changes in the CTS, any points where the Master needs to be called or informed, any weather warnings or messages, any VHF communication with other ships etc. Also, the current OOW must ask the outgoing OOW if the Master or the Chief Officer has left any verbal instructions to complied with or any night orders that there might be confusions with.
  6. Read log entries: The OOW must read any log entries made by the outgoing OOW before he leaves the bridge. If there is any confusion, he must ask the outgoing OOW of its explanation. Remember that the current bridge watch is under the responsibility of the current OOW so to reduce the margin of error as much as possible, this checking and rechecking must be done.
  7. Draft: The ship’s draft must be displayed on bridge, updated when there are any changes, for ready reference by the OOW. This is to be aware of the UKC at all times
  8. Gyro and its error: Most of the equipments on the bridge might have some errors associated with it. While they are ALL important to factored in, the gyro is something that is used at every second of the bridge watch to plan, execute and monitor the courses and any changes associated with it. Different makes of the gyro call for different inputs and some might requires input to be fed to it which means that the OOW must take precaution to ensure that its done accordingly after accounting for all errors. Needless to say, this is all under the Master’s purview and jurisdiction eventually.
  9. GMDSS: The GMDSS watch is crucial to the safety and must be maintained on the stipulated frequencies as per regulations. Additionally, all MSI promulgated via the NAVTEX or the SAT C EGC or the VHF must be checked at all times. Whether or not such information affects the ship immediately is not the primary task at hand but to obtain, read and understand such a message to determine if it affects the ship is what the OOW must do.
  10. General rounds of the ship: Soon after handing over the watch, the OOW relieved may take a round of the ship to ascertain that fire safety is maintained, there are no signs of breach, nothing unusual, no unsecured articles in the accommodation; having completed this, the outgoing OOW must inform the current OOW that such an inspection has been carried out satisfactorily and that nothing is amiss or if anything is amiss.

Additionally, the OOW must keep the following in mind:

  • Check navigational equipment in use at regular interval of time
  • Following a proper navigation plan to avoid any kind of collision according to COLREGS
  • Must know how to use Automatic Radar Plotting Aid (ARPA)
  • Must know how to use Electronic Chart and Display System (ECDIS)
  • Should be conversant with the ship’s speed, turning circles, and ship handling characteristics
  • Prepare, execute, and monitor a safe passage plan
  • Ensure handing over of the watch is done according to shipboard operation procedures (ISM)
  • Asking for support whenever required
  • Contact master when need arise
  • Should be fully aware of all safety equipment on board ship
  • Must use helm and signalling apparatus whenever required
  • Must know how to use all equipment meant for prevention of pollution at the sea and safety of lives
  • Should not leave the bridge unattended during his watch

All that is mentioned above is a generalised approach to the duties of the OOW on bridge. The full extent of such duties cannot be covered entirely as the a lot of factors may be added as per the type of the ship. For example, on tankers the IG related information has to be monitored and therefore, adds to the existing duties. The idea is for the OOW to be fully conversant with the type of the ship and all the duties that go with it. As mentioned above, the dynamic nature of it all makes the OOW’s duties dynamic as well.

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