Night navigation: essential information
Night navigation is a captivating experience, offering unique moments under a starry sky, but it also poses challenges for navigators. Navigating in the dark requires meticulous preparation to avoid unseen dangers. The safety of the crew and the ship relies on good anticipation, mastery of instruments, and increased vigilance. From recognizing navigation lights to organizing watch shifts, every detail counts to ensure a serene and successful night crossing.
Preparation before nightfall
Navigating at night offers unique sensations, but it requires methodical preparation to ensure the safety and comfort of the crew. Good planning and effective anticipation allow for a more serene approach to this experience.
Ease into it
To get accustomed to night navigation, it is advisable to start gradually. This allows the crew, especially newcomers, to familiarize themselves with the specific conditions of the night, while reducing stress and risks.
- A great way to prepare is to undertake navigations that begin at dawn or end in the evening. These situations help familiarize with the day-night transition, where light gradually decreases, providing a less abrupt introduction to night navigation. This helps better understand the nuances of reduced visibility and adapt to observing lights and markers, which become more important at night.
- For a first night navigation, it is essential to choose manageable weather. Calm conditions with little wind and a relatively flat sea provide a safer environment for acclimatization. Ideally, choose a night when the moon is visible, as its natural light facilitates navigation and makes the first experience more pleasant. Navigation becomes much more complex in the absence of natural light, especially when the sea is rough or the winds are strong.
Anticipate tasks before nightfall
One of the main rules for successful night navigation is to do as much preparation as possible while it is still daylight. Once in the dark, simple tasks can become much more complex, or even dangerous.
- During the day, it is crucial to properly organize and prepare the necessary navigation elements. For example, properly stowing halyards is essential. If they are poorly coiled or left in disarray, they can be difficult to handle in the dark, even with a headlamp. Similarly, sails must be ready, either well hoisted or folded according to the planned navigation. If you need to adjust the sails or change configurations in the middle of the night, having everything prepared in advance avoids wasting time and minimizes the risk of error.
- Checklist of elements to verify before nightfall
- Check navigation instruments (compass, GPS, AIS, radar).
- Ensure the proper functioning of navigation lights and onboard lighting.
- Ensure that all crew members are properly equipped, including with life jackets and working headlamps.
- Prepare navigation documents and maps necessary to anticipate potential dangers.
- Check the stowage of ropes and safety equipment (lifelines, harnesses).
Onboard safety: top priority
Darkness increases risks and requires heightened vigilance. A well-prepared and equipped crew is essential to avoid accidents and ensure that everyone fully enjoys the experience without putting themselves in danger. Here are the main measures to put in place to ensure safe night navigation.
Safety equipment
- The most important rule is to always wear a life jacket, even if conditions seem calm. At night, a man overboard is much harder to spot and rescue. Wearing a life jacket ensures better buoyancy in case of falling overboard. In addition to the jacket, it is crucial to always be tethered, especially in bad weather or in rough seas.
- At night, having good personal visibility is crucial, but it is equally important not to dazzle other crew members. A headlamp with a red-light mode is highly recommended. Red light provides enough visibility to read instruments or move around on deck, while avoiding impairing the night vision of other crew members.
Organizing night watches
Constant vigilance is a requirement during night navigation. The crew must be alert and ready to respond quickly to potentially dangerous situations, whether they involve course changes, nearby ship lights, or changing weather conditions.
- One of the essential rules of onboard safety is to establish shifts so that vigilance is always maintained, even in the middle of the night. An exhausted crew is more likely to make mistakes, which can have serious consequences at sea. Shifts should be organized so that each crew member has enough rest before taking their turn on watch. The recommended duration for a shift is generally 3 to 4 hours.
- Implementing paired shifts is an excellent practice to ensure more attentive and responsive monitoring. Having two crew members on deck allows for the exchange of observations, sharing of tasks, and mutual verification of decisions made. This enhances safety, as it is always more difficult to miss an important detail when two are involved.
Night navigation: regulations and interpretation of navigation lights
Navigating at night requires a deep understanding of navigation lights to ensure safety at sea. Lights play a crucial role in helping to avoid collisions and in identifying other vessels from a distance. They are governed by the International Regulations for Preventing Collisions at Sea (COLREGs), which impose strict rules for the conduct of vessels at night.
Understanding navigation lights
Navigation lights are specific light signals installed on vessels to indicate their direction, size, and status (underway, at anchor, etc.). Each type of light has a particular function that allows other boats to better understand the situation of the observed ship.
- Side lights: These are the red and green lights located on the port (left) and starboard (right) sides of the vessel. These lights project a continuous light forward with a visibility angle of 112.5°. They help to know on which side the vessel is relative to your position. If you see a green light, you know the vessel is on your starboard, while the red light indicates its presence on your port side.
- Stern light: Located at the rear of the vessel, the stern light emits a white light with an angle of 135° directed backward. It signals the position of the ship from behind, allowing other vessels to understand that they are following the ship.
- Masthead light: This white light is located at the top of the mast, at the center of the vessel, and projects a light of 225° forward of the ship. It is used by power-driven vessels underway to indicate their direction. This light is also combined with other lights on larger vessels to indicate their size and status (for example, a tug or a fishing vessel).
- All-round light: This white light emits a continuous light visible for 360°. It is mainly used by vessels at anchor and small boats that do not require side lights. This light indicates that the vessel is stationary or not in motion.
Recognizing types of vessels
Based on the lights displayed, it is possible to identify the type of vessel encountered at sea. This helps to determine the maneuver to adopt and to understand who has the right of way.
- Sailboats: A sailboat under sail must display side lights (red to port and green to starboard) and a white stern light. These lights allow other vessels to recognize a sailboat under sail. However, if the sailboat is using its engine (even in addition to the sail), it is considered a power-driven vessel and must display a masthead light in addition to the side and stern lights.
- Power boats: A power boat must display side lights (red and green) as well as a masthead light to indicate that it is underway, in addition to the stern light. For small boats under 7 meters, a simple all-round white light is often sufficient, provided the boat’s speed does not exceed 7 knots. Larger and faster boats must adhere to stricter rules with multiple lights to ensure their visibility.
- Fishing vessels: Fishing vessels actively fishing have specific lights to indicate that they are working and thus less maneuverable. A trawler actively fishing displays a white light above a green light visible for 360°, signaling that it is in the midst of trawling. Other types of fishing vessels, other than trawlers, display a white light above a red light, with side lights and a stern light only if they are in motion.
- Vessels at anchor: Vessels at anchor must display an all-round white light to signal their position. This allows other vessels to know that the boat is stationary and to avoid it during their passage.
Monitoring other vessels and avoiding collisions
Night navigation requires increased attention to avoid collisions, especially when visibility is limited. Combining constant visual watchkeeping with the use of monitoring technologies such as AIS and radar is essential to prevent accidents.
The importance of visual watchkeeping
Visual watchkeeping is a fundamental pillar of safety at sea, and it is mandatory according to the COLREGs. At night, the perception of distances and movements is altered, making the observation of other vessels’ lights crucial to avoid collisions.
- Navigation lights play a vital role at night. They help determine the direction of a ship, its type (power boat, sailboat, fishing boat), and its size. Attentive watchkeeping involves spotting lights as soon as they appear on the horizon, and monitoring them to understand the maneuvering of the encountered vessel. This allows for making appropriate decisions, including altering one’s own course if necessary, to avoid a dangerous approach.
- One of the most effective methods to prevent a collision is the use of a bearing compass. This compass allows taking a bearing on an observed ship. If the bearing remains constant, it means that the trajectory of the two vessels is converging and a collision is likely. It is then imperative to change course to avoid the accident. Generally, it is safer to pass behind the encountered vessel rather than in front, as this maneuver presents fewer risks.
Technology for collision prevention
Visual watchkeeping remains essential but can be enhanced through the use of navigation technologies, notably AIS (Automatic Identification System) and radar, which help to better monitor surrounding vessels and prevent hazards.
- AIS and radar are critical tools for tracking the real-time movements of nearby ships. These systems calculate the CPA (Closest Point of Approach), which is the minimum distance at which two vessels will come close to each other. The TCPA (Time to Closest Point of Approach) indicates the time remaining before this distance is reached. If the CPA is too small and the TCPA is short, a collision is likely. The instruments then allow for the appropriate measures to adjust the trajectory or speed of the ship to avoid any incidents.
- One advantage of these technologies is the ability to set alerts on the radar or AIS. These alerts are triggered as soon as a ship enters a dangerous proximity zone or when the CPA reaches a critical threshold. They allow for anticipating collisions and acting quickly, by adjusting the route or changing speed. Alerts, combined with attentive visual watchkeeping, provide an effective defense against collision risks, especially when visibility is reduced at night.
Managing unforeseen events: man overboard and weather conditions
Night navigation, in addition to the normal challenges of navigation, presents increased risks in case of unforeseen events, such as a man overboard or changing weather conditions. The preparation and responsiveness of the crew are essential for managing these situations. At sea, vigilance and the use of appropriate tools can make the difference between a situation under control and an emergency.
Reacting in case of a man overboard at night
Spotting a person who has fallen overboard during the day is already difficult, but at night, it becomes a real challenge. The darkness, combined with reduced visibility, makes the search and rescue much more complicated. Therefore, it is imperative to maximize the chances of quickly spotting the person and recovering them safely.
- One of the most effective ways to locate a man overboard at night is the use of strobe lights. Every crew member should be equipped with a life jacket with an automatic strobe light, which activates as soon as the person falls into the water. This type of equipment emits a powerful light signal visible from a long distance, facilitating the location of the person.
- To maximize the chances of quickly finding a person who has fallen overboard, personal AIS beacons are essential equipment. These beacons, attached to the life jacket, send a signal to nearby ships via the AIS system, indicating the exact position of the person at sea. Combined with a strobe light, the AIS beacon offers a double guarantee of rapid detection, even in total darkness. It is crucial that the crew is trained in the use of these devices, particularly in how the beacon interacts with onboard navigation systems to organize an effective rescue.
Adapting navigation according to weather conditions
It is crucial to adapt navigation according to weather conditions to avoid accidents and maintain the safety of the crew and the ship.
- In heavy weather or changing weather conditions, it is essential to reduce sail and adjust the ship’s speed to avoid unnecessary risks. Reducing speed allows for better control of the boat, limits shaking, and improves the crew’s responsiveness in case of an emergency. Moreover, a sail plan adapted to the conditions helps avoid overloading and breaking equipment, while ensuring better comfort onboard.
- At night, when external visibility is limited, navigation instruments become your best allies for monitoring weather conditions and adjusting the ship’s trajectory. The wind vane indicates the wind direction, while telltales installed on the sails show the effect of the wind on them.
Comfort onboard during night navigation
Navigating at night means not only facing the darkness but also dealing with temperatures that often drop significantly, even after a warm day. Comfort onboard thus becomes a crucial aspect to fully enjoy the experience and to remain effective during maneuvers.
Choosing appropriate clothing
- Even if the day has been warm and pleasant, temperatures at sea can drop sharply at night, and the wind can intensify this sensation. Dress warmly, especially for watch periods or nighttime maneuvers. A beanie is often essential to prevent heat loss from the head, and layers of fleece clothing are perfect for retaining body heat.
- The multi-layer clothing technique is ideal for night navigation. It involves layering several light layers rather than wearing a single thick jacket. This allows for adjusting your clothing according to conditions while maintaining a great freedom of movement. For example, a light thermal layer to regulate heat, a second insulating layer (fleece or wool) for warmth, and finally a waterproof layer to protect from wind and spray.
Protecting against the cold
- One of the most common mistakes is underestimating the cold of the night, especially after a sunny day. The heat accumulated during the day can give a false impression of comfort that quickly disappears once night falls. Not covering up sufficiently can lead to shivering, fatigue, and loss of concentration.
Mistakes to avoid include: wearing cotton clothing, neglecting protection of the head and extremities, and forgetting a waterproof jacket.
Adjusting sails and optimizing night navigation
Here are some techniques to effectively maneuver in the dark.
Adjusting the sails
- Adjusting sails is more complex at night, as it is impossible to clearly see the shape of the sails or the wind indicators, such as telltales. In the absence of sufficient visibility, it is important to rely on navigation instruments, such as the anemometer, speedometer, and wind vane. These instruments help assess the wind speed and direction, thereby facilitating sail adjustments.
- Electronic telltales are an excellent solution for accurately monitoring sail adjustments. These light-up devices, often integrated into the telltales, allow for continuous monitoring of wind direction, even at night, thus aiding in sail adjustment.
Reducing speed and prioritizing safety
Unlike daytime navigation, where speed can be optimized to reach a destination quickly, night calls for a more cautious approach. Reducing speed is often recommended to minimize risks and maintain full control over the ship.
- At night, reducing speed allows for better reaction to potential obstacles or dangers, as reaction times are often longer in the dark. With limited visibility, it is harder to anticipate course changes or spot hazards like unlit buoys, boats without navigation lights, or floating objects.
- Night navigation should primarily be safe, and this involves simplifying maneuvers. By reducing the complexity of maneuvers, potential errors, which can be more frequent in darkness, are minimized. It is preferable to maintain a stable sail configuration, without having to make frequent changes that could destabilize the crew.
Night navigation in coastal zones versus open sea
Navigating at night presents unique challenges, and these challenges vary significantly whether in coastal zones or on the open sea. Each environment has its own risks, requiring adapted navigation strategies to ensure the safety of the crew and the ship.
Navigation in coastal zones
- The main dangers during nocturnal coastal navigation are the proliferation of obstacles and the concentration of ships. Coastal zones are often frequented by fishing boats, pleasure crafts, or commercial vessels, increasing the risk of collisions, especially at night. There may also be fixed or partially submerged obstacles, such as buoys, rocks, or fishing nets, which are sometimes poorly lit or unmarked.
- The key to successful coastal navigation is constant vigilance. It is essential to maintain visual and auditory watch to detect other vessels and obstacles. Navigation instruments, such as radar and AIS, are particularly useful for monitoring the movements of nearby boats.
Navigation in open sea
- In the open sea, the main challenge is managing natural elements, such as wind and waves, which can change rapidly and abruptly, especially at night. Vessels in open sea may also encounter large ships (cargo ships, tankers) traveling at high speeds which, although visible on radars, require increased vigilance.
- In open sea, preparation and anticipation are paramount. It is essential to properly prepare the instruments before nightfall, ensuring that the radar, AIS, and wind instruments are well calibrated and functional. Maintaining a moderate speed helps avoid navigation errors and react more quickly to weather changes.
