Lesson previewLookout and Safe Speed1 section shown
Preview lesson
Lookout and Safe Speed
What you will learn
Use a continuous lookout and a condition-specific safe-speed check to create enough information, time and room for collision-avoidance decisions.
Collision avoidance starts before an encounter has a label. Rules 4–10 apply in any visibility: maintain a proper lookout, choose a safe speed, assess risk and preserve room for effective action.
Rule 5 requires a proper lookout at all times by sight and hearing as well as by every available means appropriate to the circumstances. The purpose is a full appraisal of the situation and collision risk. Looking ahead occasionally, watching only the chartplotter or assuming a second person has seen the same contact does not achieve that purpose.
Safe speed is not a fixed number. Rule 6 requires speed that allows proper and effective avoiding action and lets the vessel stop within a distance appropriate to the conditions. Visibility, traffic density, the boat's turning and stopping behaviour, background lights, wind, sea, current, nearby hazards and available depth can all change the answer. Operational radar adds further equipment and detection limits rather than removing the visual and listening task.
Rules 11–18 classify encounters only when vessels are in sight of one another; Rule 19 is the separate framework when vessels are not in sight in or near restricted visibility. That distinction matters later. The first task now is to build a reliable picture and slow early enough if the picture is incomplete.
Look-out
Risk
Action
Responsibilities
Lights & shapes
Keep the order: build the picture, assess risk, identify the applicable rule, act clearly and verify the result.
| Lookout input | Question to ask | Consequence for speed |
|---|---|---|
| Sight and hearing | What is changing in bearing, range, aspect or sound? | Slow if observation is incomplete or reaction time is shrinking |
| Traffic and hazards | How many contacts and escape constraints need attention? | Preserve room to stop, turn and avoid a second close-quarters situation |
| Boat and conditions | How will wind, sea, current, depth and load affect control? | Use the boat's actual response, not its usual cruising speed |
| Radar or AIS if available | Is the equipment working, understood and independently supported? | Treat it as additional evidence, never as the whole lookout |
Protect the observation window
You leave a quiet mooring area for a busier harbour approach. Glare hides small craft to starboard, two ferries are moving ahead and the following current increases speed over the ground.
1. Scan
Use sight, hearing and appropriate equipment across the whole horizon, including astern and the obscured sector.
2. Name the limits
Glare, traffic density, background movement and current all reduce the reliability or time available for assessment.
3. Set speed
Reduce early enough to keep control, continue observation and retain stopping or turning room before the approach narrows.
4. Recheck
A speed that was safe in the quiet reach is not automatically safe after the traffic and visibility picture changes.
Sense check: If a new contact could appear before you can assess and respond effectively, the current speed has not preserved enough decision space.
Common mistake or limitation
- A chartplotter, radar or AIS display may support the lookout; none replaces sight, hearing and a full appraisal of the current situation.
- A harbour speed limit is a legal ceiling, not proof that the same speed is safe in glare, traffic, wash, shallow water or restricted room.
- Good visibility does not remove traffic density, stopping distance, wash, current, background-light or hidden-hazard considerations.
Recap
- Rules 4–10 apply in any visibility; the observation and risk process comes before an encounter label.
- Proper lookout combines sight, hearing and all appropriate available means.
- Safe speed is the speed that preserves effective action and an appropriate stopping distance in the actual conditions.
Optional quick check
Section 1 of 1