The Yellow sea and Bohai sea areas will enter a sever ice period from January 10.In the coming week,the ice situation will continue to develop.What should ships pay attention to when sailing in ice area?
The latest warning from China’s National Oceanographic Forecast:according to the comprehensive analysis of the development of sea ice and the future weather situation,it is expected that the Yellow sea and Bohai sea areas will enter a sever ice period from January 10.In the coming week,the ice situation will continue to develop.We should prevent in advance the adverse impact of increase of sea ice on port shipping,fishing and aquaculture,maritime production safety and the live of residents in coastal areas.
China’s National Oceanographic Forecasting estimated,In the coming week(from January 11, 2021 to January 15,2021):
The largest floating ice range in Liaodong Bay is 45~55 nautical miles. Generally, the ice thickness is 10~20 cm, and the maximum ice thickness is 30 cm.
The maximum area of floe ice in Bohai Bay is 10~20 nautical miles, with a general thickness of 5~15 cm and a maximum of 20 cm.
The maximum area of floating ice in Laizhou Bay is 15~25 nautical miles, with a general ice thickness of 5~15 cm and a maximum of 20 cm.
The maximum floating ice in the north of the Yellow Sea ranges from 10 to 20 nautical miles, with a general thickness of 10 to 20 cm and a maximum of 25 cm.
Because the ice situation of Yellow sea and Bohai sea will develop in the coming week,freight forwarders must know something about ships sailing in sea ice areas.So what harm will it have if sailing in ice area,and What matters should ships pay attention?
(1) Deck icing increases the risk of crew slip and fall injury and frostbite.
(2) Ice-breaking navigation of ships has a great impact on the hull. The hull paint falls off in light cases, and the hull is deformed and broken in heavy cases.
(3) When the ship is in the ballast or light load sailing state, the floating ice and ice cubes in the ice area are easy to cause damage to the propeller and rudder blade of the ship, especially when the ship is reversing, the risk of damage to the propeller and rudder is aggravated.
(4) The cooling water inhaled from the bottom of the engine room is mixed with ice debris, which is easy to cause blockage of the bottom valve and cooling system.
(5) When the ship anchors in the ice area to be berthed, the huge ice pressure on the hull is not only easy to cause damage to the hull, but also easy to lead to anchor loss.
(6) The exposed external deck equipment, such as windlass, cable car, cargo hoisting equipment, cabin opening equipment, fire fighting and ballast piping, is easy to freeze. Many rubber pipes, apron gaskets and piping are deformed by cold or even crack, which affects the normal use.
(7) Over-filling of ballast tanks and fresh water tanks will also cause icing in water tanks and measuring tubes.
In addition, the freezing of ballast water can not be discharged, which will directly affect the cargo volume of the ship and cause losses to the voyage benefit.
(1) Prepare cold-proof and ice-proof materials.
Antifreeze in one port will be as far as possible the cold material preparation is complete, such as antifreeze alcohol (wipe on the glass can prevent bridge ice glazing), anti-freeze oil (smear on the hatch coaming, hatch covers, anchor machine to prevent freezing), antifreeze dose or industrial salt (sprinkled on deck, added to the ballast tank and anti-freezing effect in measuring tube), the crew of the clothes, shoes, caps, etc.
(2) Cooling water problem in engine room.
Navigating into the ice area, in order to prevent floating ice from blocking the sea bottom valve, it is necessary to replace the low sea bottom valve. The low sea bottom valve is deeper from the water and is not easy to enter the floating ice.
During particularly severe ice conditions, the low sea valve may also become blocked by ice, and the sea valve needs to be closed and cooled with the ship's ballast water.
(3) to avoid the damage of ice to the propeller.
On the one hand, when the heavy load enters the ice area, the fore peak tank can be emptied if necessary, and the aft peak tank can be pressed to 85%, thus increasing the aft draft.
On the other hand, try not to reverse, but be prepared to do so in case of an emergency.
Try to increase the tail draft, reverse at a low speed, send people to monitor the stern, timely communication with the bridge, to avoid large ice damage to the propeller.
(4) prevent ballast water from freezing.
Actively take anti-freezing measures to ensure that the ballast water can be discharged smoothly during loading without affecting the loading volume.
Before entering the ice zone, choose warmer water and change the ballast water.
In addition, add appropriate antifreeze to the measuring tube one day in advance to prevent the measuring tube from freezing and unable to measure water.
Once the temperature of the ballast water drops to sea water temperature after entering the ice zone, it is necessary to adopt the method of pressure drainage circulation to prevent the ballast water from freezing.
(5) Heat the fuel tank timely to ensure fuel supply.
(1) Before entering the ice area, the engine room shall consult relevant drawings in advance to prepare for internal circulation of ballast water.
In addition, equipment with exposed decks should be wrapped as far as possible to protect against the cold.
(2) Arrange the replacement of ballast water in the sea area with higher sea temperature as far as possible to lay a foundation for preventing ballast water from freezing.
Add appropriate antifreeze to the measuring tube one day in advance to prevent the measuring tube from freezing and unable to measure water.
(3) When the heavy load enters the ice area, the head peak tank can be emptied if necessary, and the tail peak tank can be pressed to 85% to increase the tail draft.
(4) It is better to enter the ice area during the day rather than large ice areas. The whiter the area is, the thicker the ice tends to be, and the bluer the ice is.
(5) Arrange the chief officer to measure the temperature of the ballast water after reaching the ice area and compare it with that of the sea water. When the temperature is close to that of the sea water, consider using the method of ballast water circulation to prevent freezing.
(6) When sailing in ice area, the ship should try to choose the thin ice area to enter vertically with the strongest part of the bow, or the sailing area recently passed by other ships.
When the ship is in the ballast or light load state, the captain should adjust the tail heave to ensure that the propeller and rudder blade sink to the water as far as possible. This not only allows the bow of the ship to ride the ice, but also helps to protect the rudder from damage.
(7) Keep regular lookout.
Early detection and assessment of sea ice conditions so that the ship can stop or change course in time to avoid danger.
In terms of route selection, the recommended route should be chosen as far as possible, and all effective means should be used to survey the ship's position frequently to keep the ship on the planned route and prevent it from falling into danger.
(8) Try not to anchor in the ice area. If you have to anchor, you should choose shallow water area with thin ice or broken ice. If it is new ice with thin brittle ice (thickness within 10 cm), water depth of 30 meters, strong current of 1.8 knots, no load, 7 knots of anchor can be thrown into the water to ensure safety.
(9) When you are trapped in the ice area, do not blindly reverse your vehicle. You can apply for assistance from a tug boat or an icebreaker.
Such as had to reverse, should be advanced vehicle steering, with out flow stern of ice away first, and then to straighten the hull, helm, back again, and stop in time, if there are any bow thrust, shall ensure that blade sank underwater again careful use, at the same time, the stern need arrange tug and ice, as far as possible to sweep crushed ice, in case of damage of propeller.
(10) The main concern for sailing in ice area is propeller damage. After sailing out of the ice area, it is necessary to test at full speed to check whether the working condition of the main engine is normal and whether the ship has abnormal vibration compared with the previous one.
Remind again: the sea ice area in the Bohai and Yellow seas will continue to grow in the coming week!
Ships should pay attention to the ice information in time and pay attention to the safety of navigation in the ice area.
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