Despite the availability of modern aids such as GPS navigators or plotters, fog navigation remains one of the major challenges for sailors. If, along with visual control, the most important feeling is lost, then some react to this cowardly and irrationally. Our author, Hinnerk Stumm, describes how not to get lost in such a situation.
Navigating in the fog: how to stay focused
Only recently everything was clear and colorful: cloudless sky, North Seashimmering blue in sunlight and reddish sandstone Helgoland on the background. Now everything seems impenetrably gray: within a few minutes everything was swallowed by the "thick soup" first by the rock Long Anna, then the sails of the yachts lying around it, and in the end these yachts themselves.
During the start of the regatta "Rund Skagen" this year 50 yachts crawled close to each other through white cotton wool, went without landmarks through an imaginary Nirvana, in which there is no longer a sense of distance. Ghostly, impersonal screams from all sides, when suddenly two colorless hulls slip past each other and just as suddenly disappear again into the gray void. It seems like you are in a bad pirate movie, however, this is just a traditional crossing between Helgoland and Keel.
The North Sea is not a sea of death, but a very difficult sailing area, for which sea fog is typical. Just at the start of the year, like Trinity this year, when a huge swath of fog from England stretched all the way to East Friesland.
Navigating in the fog: how to stay focused
Panic factor
Fog was and remains one of the most serious navigational tests: While digital assistive technology can only be a fear of running aground, collisions with severe consequences are still dangerous and still occur in modern shipping.
Probably the most famous maritime accident: collision of ships "Andrea Doria" and "Stockholm" in 1956 off the coast of Nantucket, USA, which killed 52 people.
How many search and rescue operations caused by fog are carried out annually German Society for the Rescue of the Shipwrecked (DGzRS), his press attaché Bernd Anders cannot even say, with the number of operations over two thousand, no statistics are simply kept. However, the rescuer thinks something else is important:
"Along with the danger of a collision in dense fog, there are added human factors: a sense of insecurity and panic."
In fact, the panic factor plays a decisive role, because if the most important sense organ is taken away from us, vision immediately decreases with visual control and our view into the distance: the ability to distinguish dangers in a timely manner in order to timely and appropriately respond to them.
“With a limited perception of sensations, we become less confident in ourselves, and if this is added to the lack of experience, then we begin to get nervous and make rash decisions. Simply put: fear makes you stupid, ”summarizes the influence of the psychological aspect Bernd Marek, licensed teacher of maritime affairs in DHH.
As a teacher, he sees that the practical knowledge and skills of students taking the yacht captain's certification exams have rather deteriorated in recent years:
“We can say that the basic skills and abilities of traditional maritime practice are more and more neglected, or they are often absent altogether, which will not make it possible to adequately behave in such an unusual and dangerous situation as fog.”
The fog-worn English enters in their already practically category-oriented teaching. Yachtmaster Offshore differently.
“During the so-called "Blind navigation", the examinee must show at night, without eye contact, that he is able to lead the yacht to an unknown port, using only classical navigation aids (protractor, echo sounder and sea chart) ", explains the teacher of maritime affairs from the Academy of Yacht Skippers Bernd Rese.
Passing along the isobath or strip of buoys without eye contact requires both quick response and skillful handling of navigation aids. On command to the helmsman, possible course changes are transmitted to reach the next buoy. How does the fog weather phenomenon occur?
Navigating in the fog: how to stay focused
Like clouds on water
Fog is actually nothing more than clouds that start right on the earth's surface, knows Claudia Wessing from the firm Wetter-Welt:
“It forms when humid air is cooled to such an extent that the water vapor it contains condenses and reaches the so-called dew point temperature. At this temperature, small water droplets are formed from the water vapor. "
If these tiny water droplets hovering in the air limit visibility to less than 1000 m, then meteorologists are talking about fog. The warmer the air, the more moisture it can accept without the formation of haze or fog.
"The dew point is subject to change and depends primarily on the moisture content of the air.", explains the chartered meteorologist.
There are two factors that create fog: cooling of air masses and inflow of moist air.
Fog at the start of the regatta "Rund Skagen" during "North Sea Weeks" ("Nordseewoche") arose because of the following: warm and humid air masses from the Mediterranean Sea met with the waters of the still cold North Sea, and the air cooled to condensation. Arising already to the east English Channel, the fog was carried by the southeast wind towards the shores of Germany.
We are talking about advective fog: since the water in late spring is still quite cold, while the land is already warming up to the order of the typical phenomenon.
On the contrary, in the fall: when the land has already cooled down a lot, and cold air from the land is blowing onto relatively warm water, due to evaporation, the humidity of the air rises, and with cooling to the dew point temperature, the air begins to condense: an evaporation fog occurs.
Navigating in the fog: how to stay focused
Different ways of fogging
Early spring and autumn, due to large temperature differences between land and water, is the main time for fog to appear in the North Sea and Baltic regions, although the following statement also applies: the weather can change at any time. Even the positions of the high pressure area are predetermined: the air calms down, there is no mixing, and if it cools over cold water, a fog forms.
Radiation fog on the contrary, it appears after a cold front: if it rained during the day and, therefore, the air became relatively humid, then at night, with a clear sky and little wind, the air can be very cool. Mist forms when cooled to the dew point. All this happens only with low winds, from a wind of three points on the Beaufort scale, the air masses are strongly mixed, and the air does not cool enough.
Sea currents also play a certain role: if in a sea area streamlined by a current, cold deep water is pushed to the surface due to a whirlpool and waves, then sometimes a temperature change of one degree is enough for the temperature of the humid air to drop to the dew point.
The most famous example of fog caused by sea currents is the fog bands around Newfoundland, around which warm Gulf Stream and cold Labrador current... The sea fog that arises in this way can form during a storm and be held for hours or even for several days, which I personally experienced when crossing the Atlantic from west to east.
Those who cannot see should hear: during the fog, follow the negotiations on the radio
Coastal fog can also be insidious: visibility gets worse as you approach land, making it nearly impossible to navigate shore-based landmarks. Coastal navaids, fairway barrels and approach buoys disappear into the haze just when they are most needed.
Method of occurrence: cool and humid sea air on the coast mixes with warm and also humid air from land, for example, with a blowing breeze. Since both air masses carry a lot of water vapor, the mixture can become saturated and condense: advective fog appears. Surrounded by large tracts of land, typical sailing areas like Danish South Sea, Flensburg Bay or Goare especially affected.
In late summer, this fog took us by surprise at the northern entrance to the bay. Small Belt, it had rained heavily a few days earlier and the humidity was high. In the afternoon, when we walked southerly into the open Baltic, it evaporated again, since when talking about this type of fog, we are often talking about a strip of fog located near the coast, which quickly disappears with increasing ultraviolet radiation and heat. Although, however, the fog can be carried away into the open sea.
It doesn't matter how this or that type of fog arises, the result is always the same: severely limited visibility down to zero. It is decisive that the yachtsman has a strategy of behavior, which can and should change depending on the area of sailing. After all, of course, there is a difference whether I am at a visibility range of 50 m in a strait clogged with ships Øresund or at Elbe, where, moreover, there are tides, or I go sailing in a free water area with moderate traffic.
Navigating in the fog: how to stay focused
What do the rules say?
At least in clause 19 International Regulations for the Prevention of Collisions between Ships (COLREGs) the rules of behavior in case of limited visibility are stated universally and unambiguously:
"Each vessel shall navigate at a safe speed as determined by the prevailing circumstances and conditions of limited visibility."
And the following prescriptions are given with regard to steering the ship when approaching:
“Any vessel that apparently hears a hazy signal from another vessel, apparently ahead of her beam, or which cannot prevent excessive approach to another vessel ahead of her beam, shall reduce the speed to the minimum sufficient to keep the vessel on course. It must, if necessary, stop traffic and in any case proceed with extreme caution until the danger of collision has passed. "
So the theory says, in practice everything sometimes looks different: although it doesn't seem like a good idea to do nothing and go without turning on the lights, at a constant speed on autopilot, two weeks ago just such a motor yacht sailed towards me in the bay Kolding. This means that not everyone knows the requirements of the rules and realizes the degree of danger. Since many put themselves in unnecessary danger, many nautical textbooks generally advise against leaving the port during foggy weather. Moreover, marine weather forecasts report the presence of fog and reduced visibility.
If the fog catches you by surprise at sea, it is prudent to go at such a speed that you can dodge or stop within half of the visibility distance. This is also reflected in the COLREGs.
Navigating in the fog: how to stay focused
Radar, Plotter and Company: Subjective Safety?
If there is GPS navigator or even plotter, then orientation is possible. At least to some extent, since the positioning accuracy should be within 5 meters on average, however, this is not guaranteed in areas without network coverage. In practice, it is necessary to lay an error of 50 meters between the planned route and the actual segment of the route, which is already becoming dangerous in narrow port entrances. In addition, electronic nautical charts do not take into account the transfer of buoys and deviations.
Ultimately, everyone decides for himself whether to become dependent on one single electronic means of orientation or not. Navigation on coastal objects, for example, by means of a cruiseleng, is in any case omitted. The only thing that remains in the event of a real danger is orientation and running under the engine along the isobath by compass, lot and lag in case the location is known at least approximately.
But the type of "blind navigation" mentioned at the beginning of the article provides for training; it should not be done in fog for the first time. Since the GPS navigator, in one way or another, displays only its own position, but not the position of other ships, only the one who has a radar installation on board and who can use it in a stressful situation can really feel safe, since the identification system and vessel tracking AIS issues only the positions of the courts, which, at least, have AIS transponderin enabled mode.
Anyone who wants to test their knowledge of radar installations must first do this with good visibility in order to be able to compare the image on the radar screen with a real situation, the teacher advises Bernd Rese:
“Just cover the plotter with something and, for example, practice entering a port exclusively by radar. If the boat is also driven by the tidal current, it will be really fun. "
During the fog, however, you have nothing to compare with the real situation. So Bernd Marek from DHH considers electronic aids to navigation as an effective aid to yachtsmen, but only to those who are confident in the use and operation of these devices. Lack of experience, training and competence in handling leads "In most cases, only to seeming, subjective security"... Who has a radar device or system on board AIS, that according to paragraph 7 COLREGs must actively use them.
Navigating in the fog: how to stay focused
Fog behavior at sea
If the fog caught you on the way, the whole crew must go on deck and keep watch depending on the view and the sailing area, if possible ahead, behind, on the starboard and port side.
It is very important that everyone is wearing lifejackets and belts: with a visibility range of 50 meters, it is almost impossible to find what has fallen overboard, therefore Epirb emergency beacon (or other rescue systems) should be kept close at hand, ready for use.
A similar rule applies to liferafts, which should not be in the locker, but on the deck, because ultimately, according to naval practice, the crew must always be ready for even the worst possible collision.
To maintain concentration, it is necessary to replace each other in positions every 15 minutes: after all, after a while, all sorts of things begin to appear in the fog.
If you are sailing, which is advisable even in a light wind, since hearing is now more important than sight, every two minutes you need to make one long sound, followed by two short ones. The motor must still be ready to start in order to be able to quickly disperse with a dangerous object if necessary.
If for some reason you are walking under a motor, one long beep must be emitted every two minutes. Despite this, it is necessary to walk at a low noise level and periodically turn off the engine in order to hear other sound signals. If a misty horn is heard, it is very important to find out the approximate direction.
In the tidal zone it is necessary in most cases to go under a motor.to be able to maneuver at all. In this case, a careful watch is essential, as boats on a collision course approach faster despite the reduced speed.
North Sea yachtsmen are familiar with this situation: if you are walking at a speed of 5 knots relative to the water with a countercurrent speed of 3 knots, then in relation to the surface of the earth the speed is only 2 knots! Since a yacht going with the current also gains 5 knots relative to the water, its speed relative to the ground is 8 knots. Consequently, yachts approach each other at a speed of 10 knots. In the fog, there is not much time left to make a decision; you need to be able to discern danger in time.
Navigating in the fog: how to stay focused
How to see in the fog
Radar reflector should not just be on board, but be installed at the top of the mast, since here it performs its functions for all 100 %s. An active reflector produces the best reflected signal.
According to COLREGs Navigation lights should be on both from dusk to dawn and when visibility is limited. This is prudent, as in thick haze, even in the daytime, they can be distinguished faster than the blurred outline of the yacht. In addition, the direction of movement is immediately determined.
During the ferrying of the yacht in the Solent Strait, we somehow got into such a thick fog that we had to turn on all the lights, without exception, including the masthead and deck lighting. Critics might argue that this is not a nautical principle and could lead to disaster. I understand their point of view, but with a visibility range of less than 20 m in some situations (for example, in narrow fairways, when entering a port, when moving towards each other), it is important to just be seen.
In addition, the fog layer is sometimes located only in the surface layer, and a fire at a height of 15 m, thus, may be noticed. The same as the searchlight, which has the power of 5 million candles: in extreme cases, it makes sense to turn it on at certain intervals. By the way, the practice, which is also advised by English teachers.
Navigating in the fog: how to stay focused
Safe side maneuver
A typical container ship with a stern bridge and a length of 200 m in moderately thick fog (500 m) has a visibility horizon of 300 m. To this can be added poor maneuverability, which is further impaired when the course dies down. Along with temporary and economic pressure factors, this leads to the fact that these ships (like ferries) are not very surprised by the fog and continue to follow the radars without slowing down.
Of course, you have a good chance of being seen on the monitors of their radar installations, but there is no 100% certainty: it is just small yachts that can go unnoticed, even in spite of reflectors.
On sea routes and fairways with heavy traffic, where not only sports sailing ships meet, it is necessary to develop a different strategy: to make a side maneuver.
Known courses of large ships and ferry lines should be avoided and where depth permits, walk at a safe distance outside of the barrel spacing.
When navigating coastal objects in fog, it would be appropriate to point the boat at buoys and navaids in order to compare their position with the map and get an accurate starting point for the next course.
But this is what lost its importance in the days of the GPS navigator and the plotter: it is safer not to tie your own waypoints exactly to the approach or navigation signs, but to go a little to the side at a safe distance. Even if you have to come to terms with the need to complete the detour. The probability that two ships take the same route there and collide is reduced to zero. It's about getting out of the way of large ships and minimizing the danger.
Navigating in the fog: how to stay focused
Basic Safe Tactics ...
on the water does not exist. In coastal sailing areas with heavy ship traffic, where it is so pleasant for the yachtsman to sail, it is best to maneuver where no other yacht will go in order to anchor there or wait out the changes in the situation to the accompaniment of the prescribed sound signals (see below) ...
In coastal waters, these are sheltered anchor bays, places between fixed nets or along a characteristic isobath. Away from the fairway or main approaches, the yacht is safe, as where it gets shallow, the yacht is protected from large vessels. But don't go any further than you would with good visibility. When approaching such places, you must be careful, despite the presence of a plotter, as other sailors may have already dropped the long chain and anchored in anticipation of improvement. Moderate propulsion and a conscientious watch will be advisable when approaching.
Many skippers are tempted by technical improvised means, which leads to the fact that they simply continue the transition in the fog, the teacher said. Richard Jeskerepresenting sailing school Well sailing... It should be recognized, however, that even for very experienced commercial shipping masters, navigating in fog is a huge challenge. If he had a choice, he would follow his grandfather's advice: “In foggy weather, don't stick your nose out of the house, son!"
Navigating in the fog: how to stay focused
Sound signals for limited visibility
If the ships are moving in fog, then, depending on the size of the ship, the use of different signals is prescribed: the larger the vessel, the lower the sound.
- vessels up to 40 feet (12 m) are not required to have special sound signaling devices, but must be equipped with other means of providing an effective sound signal. The foghorn, however, is a good nautical practice.
- vessels over 40 feet in length must have both special sound signaling devices on board, and a bell that is used while parking - every minute for 5 seconds
- vessels over 328 feet (100 m) in length must also have a gong on board
Sound signals and their applications
Sailing vessel: three consecutive sounds (one long followed by two short ones) at intervals of not more than 2 minutes
Power-driven vessel: one continuous sound at intervals of not more than 2 minutes
A ship not under way: two long blasts with intervals of about 2 s between them at intervals of not more than 2 minutes
Anchored vessel: ringing the bell at intervals of no more than 1 minute for 5 seconds. When another vessel approaches, an additional three consecutive sound signals with a whistle (one short, one long, one short)
Note: long beep lasts 4-6 s, short beep - 1 s
Navigating in the fog: how to stay focused
Visible horizons in the weather report
0 - 200 m: very heavy, dense fog
200 - 500 m: moderately dense fog
500 - 1000 m: light fog
0.5 - 2 nautical miles: poor visibility or very foggy
2 to 5 nm: foggy
5 to 10 nm: average visibility
10 - 25 nm: good visibility
Over 25 nautical miles: very good visibility
Text and photo: Hinnerk Stumm
03.10.2017
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