This is why CTI went to all the trouble of inventing its piloting training program, shown in this series of videos. Unless you strip the trainees of all recourse to electronics their development of the skills will happen at a very slow pace. Conversely, if you throw physical discomfort and hazard into the equation, learning will occur all the faster.
’I know exactly where we are’ has been the last words before many a grounding.
Eyes lie to everyone and instruments lie to those unskilled in using them.
I don’t think it a good reason for junior offers to neglect improving their skills but over-reliance (failure to cross-check) on visual does happen.
The pilot checked the settings on the PPU and found that there was an 18-metre offset to starboard.
The pilot was unable to remove the offset so decided to discontinue using the PPU for monitoring the ship’s progress. Instead the pilot conned the ship visually and used the ship’s radar as an aid. The pilot did not tell the rest of the bridge team that he had stopped using the PPU.
From the report:
The bridge team were all primarily navigating by eye and not verifying that what they were seeing correlated with the information in the ship’s electronic navigation systems. All of the electronic navigation aids showed that the Leda Maersk was off-track and nearing the limit of safe water to port.
Report here
Grounding of container ship Leda Maersk Otago Lower Harbour, 10 June 2018
gCaptain forum thread here: Visual Navigation Implicated in Container Ship Grounding
The title of this Norwegian poem, written back in the 19th century, could fit well as a reminder to young Navigators today?:
Source: Norwegian Folk - Løft ditt hode, du raske gutt! (English translation)
The usual method is to observe instruments and confirm visually. In high-workload situations, this approach can overload a single watch officer, requiring a second officer on the bridge. In most situations a more cognitively efficient method is to observe visually and confirm or refine with instruments; training watch officers in this approach can reduce the time two officers are needed on the bridge.
The importance of instruments such as ARPA, AIS, ECDIS, Radar etc, in marine navigation has been well established. No reasonable mariner would doubt their value.
That said, my experience at sea with visual observation is supported by science. It’s been studied formally by psychologist J.J. Gibson (also supported by Endsley’s situational awareness model and Dreyfus, Kahneman)
Gibson’s two key concepts are “Optic Flow” and “Motion Parallax”
Here’s a ChatGPT summary of those two concepts in the context of watchkeeping.
1. Visual-First = Direct Perception
When a navigator watches the scene outside, they’re not consciously measuring ranges or doing vector math. Instead, they’re reading changes in the visual field in real time.
- Optic Flow:
As own ship and other vessels move, the entire outside view is in structured motion. Threat vessels have a distinct flow pattern—remaining on a constant relative bearing while increasing in size. Non-threat vessels “slide” across the field of view.- Motion Parallax:
Closer vessels, landmarks or buoys shift position more rapidly against the background than distant ones. Even small head or body movements on the bridge give subtle but immediate cues about which objects are nearer and how fast they’re closing.
2. Why This Beats Instrument-First in High Traffic
- Instruments present processed, symbolic data—a delayed and simplified version of the scene.
- Visual scanning taps into deeply trained perceptual systems that can track multiple moving objects in parallel without conscious calculation.
- By maintaining an outside scan, the watch officer is physically engaged with the dynamic optic flow, constantly updating the mental model without having to switch between “raw world” and “instrument world.”
3. Cognitive Efficiency
- Once the mental model is visually established, verifying with an instrument is a quick, low-load check (e.g., “that ship’s bearing is steady".
- This is System 0/System 1 territory—automatic, fast, and low-effort once learned.
- In contrast, starting with instruments requires mentally reconstructing the scene from symbols, then cross-checking outside, which is slower and more prone to overload in high-traffic situations.
Bottom line: Gibson’s optic flow + motion parallax explain why the “visual first, instruments to confirm” approach works—because it uses the brain’s built-in capacity for direct perception of motion and distance, turning the outside view into a live, self-updating collision-risk display.
The use of optic flow and motion parallax to navigate is not some esoteric skill but is built into how humans navigate every day, whether on the water, walking or driving.
It’s not a binary choice of instruments vs visual observations but, in the appropriate circumstances, a matter reducing workload by using visual observations to filter or prioritize what elements require the use of instruments
An example of how folks can believe their screens over their eyes -
I was sent by an oil co to observe a ship that was aground at anchor in Stapleton Anchorage in NY with their oil on it.
When I got up to the bridge and spoke to the Master he was insistent that his vessel was not aground - pointing at his nav plotter. The conversation went something like this:
“ I understand Captain - thanks. Just a quick question - why do you think you are pointing in a different direction than these other 5 ships anchored around us ? “
That’s funny. What was the outcome for that captain?
not sure - my only job there was to watch - and do nothing. Specific orders from the lawyer. Interesting instructions - so if they do something really stupid, i am supposed to just watch it happen? Yep that’s it. Ship swung off on the next tide - no issues - went in and discharged.
I had a similar order when attending as MWS on rig moves; “observe and report but no “hands on” action”.
On one rig move in the Java Sea in the mid-1970s the Superintendent, who was giving instructions to the towing vessels, lost total control of the situation.
We were heading toward a fixed platform at speed.I grabbed his walkie-talkie and got the rig stopped before hitting the platform.
I brought the rig to a stop and pinned 100 ft. away, in position to run anchors for final approach.
The Superintendent didn’t protest but also didn’t thank me.
When I got back to Singapore I was called to the office and told that the drilling contractor had cancelled the contract because the Superintendent had reported that I had “overstepped my authority”.
Should I just have stood there and watched as the rig run into a live gas platform, note the time he lost control and the time we hit?
Not in my nature.
So, what’s the big deal about retinal optic flow? Imagine you’re on the bridge of a ship, looking out at the horizon. As you turn the wheel, the world outside your window seems to flow in a certain way. That’s retinal optic flow – the pattern of motion on your retina as you move through the environment. Nguyen’s study shows that this flow isn’t just a pretty sight; it’s a crucial part of how we navigate.
Link to the paper:Intermittent control and retinal optic flow when maintaining a curvilinear path | Scientific Reports
From the paper.
Vision is arguably one of the most complex perception senses enabling animals to navigate and exploit the ever-dynamic surrounding world as we understand it1,2,3. Although there is a scientific consensus that vision perception plays a critical role, it is not yet fully understood how humans use it to guide, propel, or control their egomotion on foot4,5 or in vehicles.
“Miss” in what context?
not bump into each other - in support of your point above
