OOW Duties and the Safe Navigational Watch

The OOW: the Master’s representative

In short: This is the first topic of Bridge & Watchkeeping: read it before the others, together with look-out and safe speed. The officer of the watch (OOW) is the Master’s representative and is primarily responsible at all times for the safe navigation of the ship and for complying with the COLREG (MGN 315 (M) 2.1, STCW A-VIII/2).

Where the rules come from

• STCW Regulation VIII/2 and Code section A-VIII/2 set the principles for keeping a navigational watch. The Master must keep watch arrangements that are adequate for a safe navigational, engineering and radio watch at all times.
• MGN 315 (M) is the UK guidance on those STCW principles. It is read together with the ICS Bridge Procedures Guide, which MGN 315 calls the principal guide to best watchkeeping practice.
• Numbering: MGN 315 (2006) cites A-VIII/2 Part 3-1. The UK STCW Regulations 2022 (regulation 56) cite Part 4-1 for the same navigational-watch principles. Same content, newer numbering.
• The Master must not be constrained by the shipowner, charterer or anyone else when taking a decision that, in their professional judgement, is needed for safe navigation (MGN 315 (M) 1.3).

The five primary duties

1. Be the Master’s representative on the bridge.
2. Keep the watch (watchkeeping).
3. Ensure safe navigation: above all, avoid collision and stranding, and take every precaution against pollution (MGN 315 (M) 2.5).
4. Comply with the COLREG, with an efficient look-out at all times (MGN 315 (M) 2.2).
5. Keep the GMDSS radio watch. STCW A-VIII/2 also sets principles for the radio watch; on most yachts the bridge is the radio room, so the OOW keeps it.

Engines and handling

• The engines are at the OOW’s disposal. Do not hesitate to use them when needed — for example to slow down and buy time in a developing situation (MGN 315 (M) 2.4, 11.2).
• Where possible, give the duty engineer timely notice of speed changes (or use the UMS engine controls properly).
• Know your ship’s handling characteristics, including her stopping distance, and remember other ships handle differently.
• The ship must always proceed at a safe speed. Schedule pressure from owners, charterers or ports never justifies putting the ship at risk (MGN 315 (M) 2.3, 11.3).

Fit for duty

• Every watchkeeper must be sufficiently rested before taking over. The Master judges fitness; the owner must man the ship so that rested, qualified people can always keep the watch (MGN 315 (M) 3.3–3.4). Baseline: at least 10 h rest in any 24 h and 77 h in any 7 days (details in the topic Hours of Rest, Fatigue and Safe Manning).
• Be free from alcohol, drugs and any medication that could affect your judgement (MGN 315 (M) 3.7).
• Stay alert: move around and keep the bridge ventilated. MAIB reports show it is all too easy to fall asleep sitting down in an enclosed wheelhouse (MGN 315 (M) 3.6).

Performing the navigational watch

In short: The OOW’s job description is in MGN 315 (M) 4.1 (STCW A-VIII/2): stay on the bridge until relieved, stay responsible even with the Master or a pilot there, call the Master when in doubt, no distractions, hand steering when it gets hazardous, radar, frequent fixes by more than one method, and a proper record.

The job description (MGN 315 4.1)

• Keep the watch on the bridge. The bridge is never left without a qualified watchkeeping officer (MGN 315 (M) 5.2).
• Never leave the bridge until properly relieved by an appropriate officer.
• With the Master on the bridge you stay responsible until they tell you specifically that they have taken the con, and both of you understand it.
• Notify the Master whenever you are in any doubt about what to do for safety.
• Take on no other duties that would interfere with the watch.
• No distractions: no domestic radios, music players, personal computers, TV or mobile phones.
• Have a qualified helmsman available at all times.
• Put the ship in hand steering in high traffic density, in restricted visibility and in all hazardous situations — in good time. On autopilot, never let a situation build until you are alone and must break the look-out to take emergency action.
• Remember that officers on ships of different type and size judge a close-quarters situation, and the time to act, very differently.
• Keep a proper record (log) of the movements and activities of the watch.

Radar, position and charts

• Radar: use it at all times in high traffic density and whenever restricted visibility is met or expected, with due regard to its limits. Keep it available at all times and use it in clear weather too, so you learn its limitations (MGN 315 (M) 4.1).
• Check position, course and speed at sufficiently frequent intervals, with all appropriate aids, so the ship stays on the planned track.
• Take fixes at frequent intervals, by more than one method whenever possible.
• Use the largest-scale chart on board for the area, corrected up to date — including local navigational warnings and T&Ps. All publications (lights, radio signals, pilot books) in the latest corrected edition.
• On a ship with a separate chartroom you may go there briefly, only when essential, after making sure it is safe and the look-out is kept (MGN 315 (M) 8.4).

Many revision lists shorten this to “use the radar at all times”. MGN 315 is more precise: use it at all times in high traffic and in restricted visibility, keep it available at all times, and practise with it in clear weather.

With a pilot on board

• A pilot advises; the Master stays responsible for the ship and approves the pilotage plan.
• When the Master is not on the bridge, the OOW remains the Master’s representative and stays responsible for safe navigation despite the pilot (MGN 315 (M) 4.1).
• Use the pilot’s advice to carry out the planned passage, and keep monitoring position and track yourself.
• In doubt about the pilot’s actions or intentions: 1. ask the pilot to clarify; 2. if still in doubt, call the Master at once; 3. take whatever action is needed until the Master arrives.

Composing the watch and working with the look-out

In short: A watch is one or more qualified officers supported by qualified ratings, sized to the conditions. Underway, a separate dedicated look-out is the norm; the look-out duty itself is COLREG Rule 5, covered with Rule 6 in its own topic. Treat the look-out as part of the bridge team and keep them informed.

What decides the size of the watch

MGN 315 (M) 5.3 — factors when composing a bridge watch:

• fatigue;
• weather and visibility;
• proximity of navigational hazards that give the OOW extra navigation work;
• use and condition of navigational aids;
• whether the ship has automatic steering;
• radio duties to perform;
• UMS (unmanned machinery space) alarms, controls and indicators on the bridge;
• any unusual demands from special operations.

Where a single-person bridge is accepted, support personnel must be readily and immediately available, with a means of calling them that works at all times.

The dedicated look-out

• The MCA reads STCW as requiring a separate dedicated look-out, in addition to the OOW, whenever the ship is underway (MGN 315 (M) 2.7).
• The MCA considers it dangerous and irresponsible for the OOW to be the sole look-out in darkness or restricted visibility (MGN 315 (M) 2.6).
• The look-out gives full attention to that job, with no other duties.
• The helmsman is not the look-out, except on small vessels with an unobstructed all-round view from the steering position and no loss of night vision (MGN 315 (M) 8.2, STCW A-VIII/2).

Keeping the look-out engaged

• The look-out is an integral part of the bridge team: use them to the full (MGN 315 (M) 9.1).
• Keep them briefed on what to expect: traffic, buoyage, weather, landfall, pilotage and anything else relevant (MGN 315 (M) 9.2).
• On the bridge: “Expect the TSS entrance buoy fine on the starboard bow in about 20 minutes, and fishing boats to port” turns a passive look-out into an active one.

When can the OOW be the sole look-out?

In short: Only by day, in clear daylight, and only when the Master has decided — each time — that it is safe (MGN 315 (M) 8.3, STCW A-VIII/2). Help must be immediately available.

What the Master must weigh

On each occasion the situation is carefully assessed and it is established without doubt that it is safe, taking full account of (MGN 315 (M) 8.3):

1. the state of the weather;
2. the visibility;
3. the traffic density;
4. the proximity of dangers to navigation;
5. the attention needed when navigating in or near traffic separation schemes;
6. the design and layout of the bridge;
7. the arcs of visibility from the conning position;
8. the radar fitted and its limitations;
9. other duties that could distract the OOW from the look-out:
   • GMDSS and other communications — phones and email;
   • navigational admin — logs, records, chart and publication corrections;
   • routine testing and maintenance of bridge equipment.

The conditions that never go away

• As sole look-out the OOW must still be able to do both jobs fully: look-out and safe navigational watch.
• Assistance must be ready to be summoned to the bridge immediately if anything changes.
• At night or in restricted visibility: never sole look-out (MGN 315 (M) 2.6). A typical Master’s standing order posts an extra look-out from sunset to sunrise.

Scenario: you see a vessel aground

In short: A grounded ship is a warning that the water there is shallower than you may think. Inform the Master, check your own position and depth, slow the situation down, and use the other ship’s draught and time of grounding to judge the shoal.

Your actions, in order

1. Advise the Master of the vessel aground.
2. Carry out a chart assessment: plot your own position and the position of the grounded vessel.
3. Switch on the echo sounder and note the under-keel clearance.
4. Post look-outs and change from autopilot to hand steering.
5. Call the grounded vessel (VHF, with proper station identification) and get her draught and the time of grounding.
6. Assess the extent of the shoal she has run onto, and keep well clear of it.

Why each step matters

• Her draught plus the time (and so the height of tide then) tell you roughly how much water there was over the shoal — and whether your draught is at risk.
• A grounding where the chart shows safe water may mean an uncharted or moved danger: trust the sounder and the evidence, not just the chart.
• Identify her by her lights and shapes: aground = anchor light(s) plus two all-round red lights in a vertical line; by day three balls in a vertical line (COLREG Rule 30(d)).
• Hand steering and extra look-outs follow the job description: a hazardous situation means manual steering in good time.