Seeing is believing? - The Navigator Issue 37

Like any cognitive skill, visual perception skills can vary from person to person. The good news, however, is that, like any skill, it can be improved. Captain Aly Elsayed AFNI, Senior Technical Adviser at The Nautical Institute, explains how.

Visual perception is the brain’s ability to process and interpret visual information from the environment. In navigation, being able to tell the difference between different shapes and objects is crucial, as is the ability to recognise and recall these forms and picture them in various orientations. This is particularly important for tasks such as recognising landmarks, following specific visual tracks or identifying hazards and targets.

Interpreting the visual scene

There is a great deal of emphasis on the importance of keeping a good lookout – and rightly so. However, it is also important to know what you are actually looking at. In other words, you must be able to interpret the visual scene and relate it to what your various charts and instruments are showing you.

A student who has not yet joined their first ship can easily recognise the buoyage system or cardinal buoys on the charts or ECDIS screen in front of them because they are visually standardised. This may not be the case at sea though. Four buoys that look identical on the chart may appear very different in reality, due to their design, location and physical conditions.

Recognising and interpreting these differences is all part of visual perception. We use the same methods to recognise the actual appearance of buoys, channels, terminals, targets, heavy traffic and so on in varying conditions, day or night. Although the symbols on the chart always stay the same, what you actually see in real life will vary depending on water depths, ship position, background, traffic locations, sea state, visibility and many other factors.

Even if there is no chart involved, what you think you are seeing with your eyes may be quite different to what is actually there. Darkness or fog can make interpreting visual information particularly challenging. Scale can also play tricks: a bigger ship can appear closer than a smaller ship even though it is actually further away; a VLCC in ballast condition will look larger than the same vessel when it is fully loaded. A port entrance or passage between islands may seem to be very narrow, or even invisible, as you come to it from the side, and only be apparent as you approach it head on. This is called parallax error. In some ports and in some vessels, it may be necessary to begin a turn before you can actually see the space you are turning into.

Visual sequential memory

Navigators tend to have better situational awareness when they have a mental picture of both:

• where landmarks and navigation aids are relative to the ship, and
• where those landmarks and navigation aids are relative to each other.

Interpreting cues from visual information (including navigational aids), along with using those cues to identify potential hazards and make precise decisions, is known as wayfinding.

Being able to remember and recall a sequence of visual information is essential for maintaining situational awareness while navigating. This might include the symbols on a chart, the shape of a headland or the sequences of leading marks when entering harbour. This skill is especially relevant when navigating through dynamic and changing environments, such as port approaches and areas of heavy traffic. It is a primary aspect of successful navigation during fog or sandstorms when visual information is obstructed, or if information from navigational equipment is unavailable because of system or sensor failure.

Understanding and being able to picture the likely sequence of events, as well as what you will see at each stage, is important because your decisions should be based on the process as a whole, not on individual elements of it. That way, you are cross-checking your own work.

Visualisation

‘Visualisation’ means creating images within your mind, or picturing the steps within a process – what might be referred to as ‘mental practice’. It helps break down complex problems into manageable steps and identify solutions effectively.

Actively practising mental imagery exercises can help maintain and strengthen your visualisation skills and prepare you for different scenarios. Imagine an experienced tanker Master who is assigned to navigate through the Singapore Strait for the very first time. They turn to the sailing directions, ECDIS and Singapore Guide Charts. These documents give a guided visual task, filled with detailed information about the strait’s characteristics, limitations, turns, speed, depths, current traffic, guidelines, etc. The Master can use all of this information to prepare and envision each stage of the passage (appraisal, planning, execution and monitoring) and how they might need to react to various scenarios.