Bridge Watchkeeping Duties: Keeping a Safe Navigational Watch

It is 0345 on the middle watch. The wheelhouse is dark except for the soft glow of the radar and the ECDIS. The master is asleep two decks below. Ahead, a cluster of fishing boats works the edge of a bank, their lights smeared by drizzle, and a contact fine on the starboard bow has held its bearing for the last six minutes. For the next four hours, every decision about where this ship goes and how she avoids that contact belongs to one person: you, the officer of the watch.

That is what bridge watchkeeping duties come down to. Not a tidy checklist of tasks, but the continuous, undivided responsibility for the safety of a ship and everyone aboard her while the rest of the crew sleeps. This guide walks through what the officer of the watch (OOW) is responsible for on a live bridge, the rules that define those duties, and the judgment that holds them together.

If you are new to the watch system itself, our guide to watchstanding basics covers the rotation and the reasoning behind it. This article is about the duties you carry once you have the conn.

The Officer of the Watch Has the Conn

When you take over a navigational watch, you become the master’s representative on the bridge. Your primary responsibility, above everything else, is the safe navigation of the ship. Every other task on the watch sits beneath that single duty.

That carries real authority. You have the conn: the conduct of the ship is yours, and you give the helm and engine orders. It also carries a hard limit on stepping away. The standards under STCW are explicit that you keep your watch on the bridge and do not leave it until you are properly relieved. Even when the master comes up to the bridge, you remain in charge of the watch until the master formally and specifically takes over the conn. A master standing beside you is not the same as a master who has the conn. Until those words are spoken, the ship is still yours.

The flip side of that authority is honesty about its limits, which is why so much of what follows is about recognizing when a situation has outgrown a single watchkeeper.

Keeping a Proper Lookout

Everything else depends on this one. Maintaining a proper lookout is the first duty named in the COLREGs, and it is the duty most often found missing in the reports of ships that collided. Rule 5 requires a lookout by sight and hearing and by all available means appropriate to the conditions, so that you can make a full appraisal of the situation and of the risk of collision.

“All available means” carries a lot of weight in that sentence. Your eyes and ears come first, but radar, ARPA, AIS, and the ECDIS are part of the same picture, cross-checked against one another rather than trusted blindly. No single screen tells you the whole story, and the officers who get caught out are usually the ones who stopped looking out of the window.

Two practical points trip up new officers. First, the lookout and the helmsman are separate functions: a rating hand-steering at the wheel is not keeping a lookout. Second, you may act as sole lookout in daylight only, in good visibility, with nothing else reducing your ability to see, and only after a careful assessment that it is genuinely safe. At night, in restricted visibility, or in heavy traffic, you post a dedicated lookout. There is no judgment call to agonize over there.

Avoiding Collision: Reading the Traffic

A proper lookout exists so you can answer one question continuously: does risk of collision exist? Under the COLREGs, if you are in any doubt, you must treat it as though it does. A contact whose compass bearing does not appreciably change while the range closes is the classic signature of a developing collision, and the one on the starboard bow at 0345 has been doing exactly that.

Detecting risk early is what gives you room to act. Begin radar plotting or systematic observation in good time, and remember that you can buy time by reducing speed. When you take action to avoid collision, the rules want it to be early, substantial, and obvious to the other vessel, not a string of small alterations that leave everyone guessing about your intentions.

In restricted visibility the standard tightens further, and the full set of give-way and stand-on obligations sits in our complete guide to the COLREGs. The point to carry onto the bridge is simpler: collision avoidance is not an occasional event during the watch. It is the lens you keep over the whole watch.

Monitoring the Passage and Fixing the Ship’s Position

While you watch the traffic, you are also holding the ship on her planned track. The passage plan runs berth to berth, and the watch is where it is executed and checked. You confirm each course before you steer it, monitor cross-track error, and fix the ship’s position at intervals frequent enough for the waters you are in: rarely in open ocean, almost continuously in pilotage.

The discipline that matters here is cross-checking. GPS feeding the ECDIS is convenient and usually right, but a single source can fail quietly, so you confirm it against an independent method whenever the situation allows, whether by radar ranges and bearings, a visual fix, a transit, or a line of soundings. Our guide to position fixing methods covers those techniques in detail.

The echo sounder earns its place here too, used as a continuous check against the charted depth. Keep an eye on set and drift, because the heading you are steering and the track you are making good are rarely the same line, and the difference is where ships quietly end up somewhere they did not plan to be.

Giving Helm and Engine Orders

When you put a helmsman on the wheel, the bridge runs on standardized language for a reason: there is no room for “a bit more right.” Wheel orders follow the IMO Standard Marine Communication Phrases, and every one of them is given, repeated back, and confirmed. That loop is called closed-loop communication, and it is what catches a misheard order before it becomes a wrong turn.

The core wheel orders follow a fixed pattern. Each is given, repeated by the helmsman, and held until you countermand it.

Order	Meaning
Port / starboard five (ten, fifteen, twenty, twenty-five)	That many degrees of rudder, held until countermanded.
Hard a-port / hard a-starboard	Rudder put fully over to the side ordered.
Midships	Rudder returned to the fore-and-aft position.
Ease to five (ten, fifteen, twenty)	Rudder reduced to the stated angle and held there.
Meet her	Check the swing of the ship’s head in a turn.
Nothing to port / nothing to starboard	Do not let the ship’s head go to the side named.
Steady	Reduce the swing as rapidly as possible.
Steady as she goes	Hold the heading shown on the compass at the moment of the order; the helmsman repeats it and calls it back, for example “steady on one-eight-two.”
Port / starboard, steer [course]	State the direction the wheel turns, then each digit separately, for example “port, steer one-eight-two.”

The helmsman repeats every order before executing it and reports at once if the ship does not answer the wheel. If you suspect inattention, you ask “what is your heading?” and expect an immediate reply. The change between hand steering and autopilot is a deliberate, announced action, never an absent-minded flick of a switch, because the moment you most need manual steering is exactly the moment you cannot afford confusion about which mode you are in.

Standing Orders, Night Orders, and When to Call the Master

You do not keep the watch on instinct alone. Every master is required to issue standing orders, written instructions kept on the bridge that set the standard for how watches are run on that particular ship. On top of these, the master writes night orders in the night order book before turning in, with specific guidance for the hours ahead: expected traffic, a closest-point-of-approach limit, a position to be called at, a waypoint to watch for.

Beneath all of that sits the single most important instruction on any bridge: call the master. When in doubt, call.

The principle that overrides every hesitation is this: calling the master early is never the wrong call, and while you wait for the master to arrive, you do not hold back from taking immediate action to keep the ship safe.

The same discipline applies with a pilot aboard. The pilot’s presence does not relieve you of your duties. If you are in any doubt about the pilot’s actions or intentions, you query the pilot directly, and if doubt remains, you notify the master and take whatever action the situation demands.

Handing Over the Watch

A watch is only as safe as its handover. Before you take over, you must be rested, fit, and adjusted to the darkness, and you do not assume the watch until your night vision is fully adjusted to the light conditions. The relieving officer personally satisfies themselves of the essentials: the master’s standing and night orders, the ship’s position, course, speed, and draft, the prevailing and forecast weather, visibility, tides and currents, the traffic situation, any navigational hazards expected during the watch, and the status of the bridge equipment.

The outgoing officer carries a duty too. If there is any reason to believe the relieving officer is not capable of taking the watch, whether through fatigue, illness, or anything else, the handover does not happen and the master is informed.

One rule sits above the rest: you never hand over in the middle of a maneuver. If the ship is altering to avoid a contact or working through a close-quarters situation, the relief is deferred until that action is complete and the situation is clear. Responsibility changes hands at a quiet moment, not at the worst one.

Fitness for Duty and Bridge Resource Management

A tired watchkeeper is a hazard the same way a defective radar is a hazard, and the rules treat fatigue accordingly. Watchkeepers are entitled to a minimum of ten hours of rest in any twenty-four-hour period and seventy-seven hours in any seven-day period, and sobriety is not left to discretion: the blood alcohol limit for anyone performing safety duties is set at 0.05 percent, or 0.25 milligrams per liter on the breath. Turning up rested and clear-headed is itself part of the job.

The duties above are easier to picture as one officer’s responsibility, but a safe bridge is a team, even when that team is just you and a lookout. Bridge Resource Management (BRM) is the practice of running that team well: clear communication, shared situational awareness, defined roles, and a culture where a junior officer, a helmsman, or a lookout is expected to speak up when something looks wrong. Most accidents at sea are not a single catastrophic failure but a chain of small ones, and any member of the bridge team can break that chain. Building a watch where people feel able to do so is as much a watchkeeping duty as fixing the position or reading the radar.

Frequently Asked Questions

What are the main duties of the officer of the watch? The OOW is responsible for the safe navigation of the ship while on watch. That breaks down into keeping a proper lookout, avoiding collision under the COLREGs, monitoring the passage and fixing the ship’s position, giving helm and engine orders, complying with the master’s standing and night orders, and calling the master whenever a situation calls for it.

Can the officer of the watch leave the bridge? No. The OOW must keep the watch on the bridge and may not leave it until properly relieved. The bridge is never left without a qualified watchkeeping officer in charge.

When must the OOW call the master? Whenever in doubt, and specifically when visibility deteriorates, when traffic causes concern, when an expected light or landfall does not appear, when equipment fails, in heavy weather or ice, or when the passage changes unexpectedly. Calling early is never a mistake, and the OOW takes immediate action for safety in the meantime.

What is the difference between standing orders and night orders? Standing orders are the master’s permanent written instructions for how watches are run on that ship, kept on the bridge throughout the voyage. Night orders are written fresh in the night order book each evening with specific instructions for the coming night, such as traffic to expect or a position to be called at.

Can one officer keep the bridge watch alone? Only in daylight, in good visibility, with nothing reducing the ability to see, and after a careful assessment that it is safe. At night, in restricted visibility, or in dense traffic, a dedicated lookout must be posted, and the lookout and helmsman are always separate roles.

Who is in charge of the watch when the master is on the bridge? The OOW remains in charge until the master formally and explicitly takes over the conn. The master being present on the bridge does not by itself transfer responsibility.