Study shows many collisions occur in clear weather, with the other boat in plain view
Study shows many collisions occur in clear weather, with the other boat in plain view
It seems impossible to miss seeing a nearby boat on the water in clear weather. We assume everything that can be seen is seen.
However, it is quite commonplace to miss seeing something significant, and sobering to realize that some 30 percent of collisions reported to the Coast Guard are due to failure to see the other boat in time — or at all. Yet visibility is reported as fair or poor in only about 1 percent of the collisions.
Consider these two accidents, which occurred in clear weather, in the daytime, and with few other vessels around.
• An outboard boat is running down the Intracoastal Waterway at planing speed, testing a new engine. The operator doesn’t see a daymark in time, and the boat hits it. There is a fatality.
• Two boats approach each other at planing speed near the New Jersey coast. One boat stops just ahead of the other, and not one of the six people on the two boats sees the other boat until seconds before the collision. Three men die.
Why do so many boat operators simply fail to see another boat on a collision course, or for that matter a fixed object, in clear weather? It’s often the failure to post a proper lookout. Few duties are as important to the skipper as that of lookout. In fact, keeping a careful watch has been called “the first rule of good seamanship.” Yes, the skipper has to keep the boat afloat, stable and out of harm’s way, but the task of lookout is inextricable from the goal of avoiding collisions. Unfortunately, the lookout task is far more complex than many people realize.
A number of years ago the Coast Guard began to examine collisions to determine the most frequent causes. They sponsored a series of research studies on collisions between recreational boats, which produced some surprising results. The studies involved three methods: analysis of accident statistics, detailed interviews and analysis for a group of accidents, and on-water tests to measure visual performance.
All three lines of inquiry indicated that lapses in lookout performance, specifically failure of operators to see boats in clear view, are quite commonplace aboard recreational boats. The project began by specifying the scope of the work, then screening all accidents for one year. The second phase of the study delivered some important conclusions relating to the visual task, which had become obvious as a primary cause of accidents. Another report examined 104 collisions in depth and concluded that visibility problems probably were the cause in 30 of the mishaps, and possibly 31. The researchers wrote, “This … dramatically shows the role visibility plays in collisions.” (Visibility refers to seeing, not a lack of clarity in the atmosphere.)
Another effort involved careful observations aboard a boat equipped with an optical array designed to present visual targets at various locations within the operator’s normal field of view. The experiment verified that the combined daytime stressors — such as heat, glare, noise, vibration and fatigue — have a detrimental effect on visual performance. The experiment was specifically designed to measure the effects of fatigue and alcohol consumption, and concluded “that fatigue and alcohol are stressors that lead to significant degradations in performance. The sizes of the effects were almost the same. … The fatigue result was interesting in that the activity levels of the subjects were not greater than those that might be witnessed on a typical outing.”
In other words, the degradation in visual target detection is about as significant for a skipper fatigued by operating the boat for a few hours in good weather as it is for one who had been drinking enough alcohol to be arrested for operating under the influence.
The final report included results and analysis of previous research, as well as these statistics.
Of the 4,308 vessels having damage, injuries or fatalities, the following was reported:
• 78 percent of the operators had 100 hours or more boating experience.
• In 79 percent of the cases the weather and visibility were good.
• In 56 percent of the cases the water was calm, while only 24 percent of the cases reported the water as choppy.
• In 63 percent of the cases the wind was reported as none to light.
• Of the 120 “other deaths,” 45 percent of the vessels had a collision with another boat or an object.
• Of the 3,127 vessels damaged, 50 percent were cruising at the time of the accident, and 49 percent had a collision with another vessel.
The report further states, “These statistics lead one to suggest that it may not be the unskilled beginning boater who loses control of his vessel in rough water that causes the majority of accidents; but rather, it is the experienced operator cruising in other than rough water who collides with another object which he either did not see in time to avoid, did not recognize as being on a collision course with him, or did not know how to avoid with his particular skill, knowledge or experience level.”
It is important to note that the people participating in the experiments were healthy young men with extensive experience aboard boats.
The report also concludes, “ ‘Inattention’ probably accounts for 22 percent of the probable collision causes. This inattention can be interpreted as the operator’s failing to process and/or act on the visual information which should have been used to avoid the collision.”
The controlled experiments found specific visual effects of fatigue. “As fatigue increases, subjects spent less time looking at the instrument panel, decreased the amount of time spent looking directly ahead of the boat but above the horizon, and increased the amount of time spent looking ahead of the boat but between the bow of the boat and the horizon.”
The researchers found that such stressors as fatigue, velocity and traffic density tended to affect visual performance adversely. They also documented direct evidence of the experienced skippers simply failing to see approaching boats. During 50 hours of controlled under way experiments, “There were a number of instances in which the boat operator subjects did not see traffic which was on potentially collision courses, and one of the experimenters would have to point out traffic to avoid a potential collision.”
In the years following these experiments, scientists have done significant research into the problem of failing to see objects that should be clearly visible. It turns out that we must focus our attention on an object in the field of view in order to see it. Just looking around doesn’t work. The eyes seem to “wallpaper over” objects that we don’t see with something like a background image. Only when we look at an object and give it our attention does it appear in our sight.
The scientists call this phenomenon inattentional blindness, and although it contradicts our ideas of vision, research has shown it to be true. Arien Mack and Irvin Rock have done extensive research on the various aspects of inattention on vision, and have published the book “Inattentional Blindness” (MIT Press, 2000) describing their experiments and conclusions.
This failure to see has important implications for witnesses of accidents, as well as for lookouts. It is evident that preoccupation, concentration on something else, or fear can prevent us from seeing important objects in our field of view. Researchers are continuing to explore and understand the problem and how to compensate for it. (If you’re looking for more on this complex topic, a Web search will yield a variety of sites with more information.)
On a boat we have to keep a good lookout, and inattentional blindness affects our ability to do so in ways that are yet to be fully understood. The International Regulations for Preventing Collisions at Sea and the Inland Navigation Rules contained in the booklet Navigation Rules, International-Inland (USCG COMDTINST M16672.2D) have identical rules for lookout, as follows:
Rule 5 Lookout
Every vessel shall at all times maintain a proper lookout by sight and hearing, as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.
The courts have interpreted Rule 5 as requiring a lookout who is:
• qualified by experience
•a person with good sight and hearing
• vigilant and alert
• free from other duties, except sounding a fog signal
•properly stationed, low and forward
•in communication with the bridge [primarily large ships]
• in such numbers as circumstances require [primarily large ships]
These requirements come from long experience that recognizes failure of any one of them detracts significantly from the task of keeping watch. In particular, many courts have found that people who have other duties in addition to lookout are unable to adequately fulfill the requirements of that task. This is true aboard boats and ships alike. The courts have held consistently that boat operators have a duty to maintain proper lookout. If there is no lookout assigned, the helmsman can be held at fault in an accident unless it can be proven that the lack of a lookout wasn’t a contributing factor.
Traditional methods of searching seem to account for some aspects of inattentional blindness. We teach lookouts to search in sectors, out from the ship or back from the horizon, and in “steps” in between. This requires a lookout to focus on each small portion of the sea, one portion at a time. It is a time-proven method to avoid missing things that we can see when we concentrate on them.
Many of the things relating to boats seem logical once we understand their physical or mathematical aspects. This is not true of inattentional blindness. It seems to run counter to our common sense. We must work to overcome the limitations that it imposes on our sight.
We need to avoid dividing our attention between lookout and another task. We should ask our passengers or children to help. We can search, rather than scan. We must look around before making a maneuver. And we can rotate the task of lookout. These practices will help us to see everything that is important to our safety.
Capt. Bill Brogdon is a retired Coast Guard officer with many years of ship and boat experience.