Every year, the period from late March to early July is the key period for the occurrence of dense fog on the sea in Weihai, with an average of more than 15 foggy days. Sea fog is caused by the condensation of water fog in the lower atmosphere of the sea surface. It is usually milky white. According to different causes, sea fog is mainly divided into advection fog, mixed fog, radiation fog and topographic fog. It often reduces the visibility of the sea surface to less than 1000 meters and does great harm to the safe navigation of ships.
1. What are the characteristics of ship fog navigation?
· The visibility is poor, and the line of sight is limited.
· Due to poor visibility, it is impossible to find the surrounding ships at a sufficient distance, and quickly judge the other ship’s movement and the other ship’s avoidance action, only relying on AIS, radar observation and plotting and other means, so it is difficult for the ship to avoid collision.
· Due to the limitation of the line of sight, the nearby objects and navigation marks cannot be found in time, which causes great difficulties in positioning and navigation.
· After the safe speed is adopted for navigation in fog, the influence of wind on the ship is increased, which greatly affects the accuracy of calculating the speed and voyage, which not only reduces the accuracy of calculating the ship’s position, but also directly affects the safety of navigation near dangerous objects.
2. What aspects should ships pay attention to when navigating in fog?
· The offshore distance of the ship shall be adjusted in a timely and appropriate manner.
· The officer on duty shall carefully carry out the track reckoning work.
· The actual visibility distance under the current visibility condition shall be mastered at all times.
· Listen to the sound signal. When hearing the sound signal, the ship shall be deemed to be in the danger area, and all necessary measures shall be taken to avoid danger. If the sound signal is not heard in the position that should be heard, it should not be arbitrarily determined that the danger zone has not been entered.
· Carefully strengthen the lookout. A skilled lookout must be able to detect any minor changes around the ship in time.
· All available means should be used as far as possible for positioning and navigation, in particular, radar should be fully used.
Post time: Mar-13-2023