The design draft of a ship is tons, and the waterline of the ship usually refers to the summer load line of the ship, which is represented by S (there are two waterline signs in China and internationally), indicating that the proposed draft and summer area of the ship are the maximum draft depth. Let's take a look at the design draft dwt of this ship.
The design draft tonnage of a ship is 1, which refers to the maximum water that can be discharged by the ship, that is, the total mass of the ship and cargo; The deadweight refers to the displacement minus the mass of the ship. The tonnage of a ship shows its size and transport capacity.
It can be divided into two categories: volume tonnage and weight tonnage: volume tonnage is the unit of measurement based on the "ton" specified in the ship registration, and each ton is equivalent to the volume of 2.83 cubic meters, which is the international general statistical unit of ships and reflects the size of ships; Weight tonnage refers to the weight that a ship displaces the same volume of water in water, including empty weight and full weight, which can indicate the ship's load transport capacity.
Generally, the ship displacement is described as follows:
No-load displacement: refers to the weight of empty ship. Including engine oil and water, but excluding aviation fuel, lubricating oil and boiler water;
Full load displacement: including jet fuel, lubricating oil, boiler water and personnel, goods, grain, fresh water, etc. That is, no-load displacement+design load.
The above are divided into departure and arrival. The former refers to sufficient materials, while the latter refers to consumption 10%. If there is no special instruction, the port is indicated. Full-load departure displacement is the maximum displacement, and it is also the design displacement of civilian ships.
Usually, a 10,000-ton ship refers to the load 1 10,000 tons, not the displacement 1 10,000 tons.
For warships, it is divided into more detailed points:
No-load displacement: empty ship, excluding personnel, luggage, fuel, lubricating oil, boiler water, grain, fresh water, ammunition, etc.
Standard displacement: fully prepared. Including fuel oil, lubricating oil and boiler water required for start-up, excluding navigation fuel oil, lubricating oil and boiler water;
Normal displacement: navigable, carrying 50% fuel oil, lubricating oil and boiler water. This is the design displacement of warships;
Full load displacement: carrying a full range of materials. Under normal circumstances, the maximum loading state of the ship when sailing;
Maximum displacement: overload displacement. Plus overloaded ammunition and completely filled with fuel, lubricating oil, boiler water, etc. This is the maximum loading state allowed for warships.
Displacement is the state that a ship can sail at a suitable draft. In fact, there is a reserve buoyancy above the full displacement to ensure that the ship will not sink after being damaged. Generally, 20-50% are seagoing ships, and 100% are military ships.
Although these displacement divisions are cumbersome, they are an important basis for ship design and entry and exit operations.
Ship design draft deadweight ton 2 ship weight tonnage
1, displacement tonnage
The tonnage of displacement is the tonnage of boiling water discharged by the ship in the water, and it is also the tonnage of the ship's own weight. The tonnage of displacement can be divided into light displacement, heavy displacement and actual displacement:
1) optical displacement
Also known as empty ship displacement, it is the ship itself plus crew and necessary supplies.
The sum of these quantities is the minimum weight of the ship.
2) Large displacement
Also known as full load displacement, it is the displacement when the draft of the ship reaches the maximum load line after carrying passengers and goods.
Weight refers to the maximum weight of the ship.
3) Actual displacement
It is the actual displacement of the ship after each voyage. The calculation formula of displacement is as follows:
Displacement (long ton) = length * width * draft * modulus (cubic feet) /35 (seawater) or 36 (fresh water) (cubic feet)
Displacement (metric tons) = length * width * draft * modulus (cubic meter) /0.9756 (seawater) or 1 (fresh water) (cubic meter)
Displacement tonnage can be used to calculate the deadweight tonnage of a ship; In shipbuilding, according to the displacement
Tonnage shows the weight of the ship; When counting the size and fleet of warships, light displacement is generally used as the standard;
The warships passing through the Panama Canal are taxed according to the actual displacement.
2. deadweight tonnage
Indicates the load capacity that the ship can use in operation. The deadweight tonnage can be divided into gross deadweight tonnage and net deadweight tonnage.
1) gross tonnage
Refers to the maximum weight that a ship can bear according to the load line mark, including the sum of the weight of the goods carried by the ship, the fuel needed on board, fresh water and other reserve materials.
Gross deadweight ton = full load displacement-empty ship displacement
2) Net deadweight ton
Refers to the maximum weight of the goods that a ship can carry, also known as the loaded tonnage, that is, the disembarkation weight.
The difference obtained by subtracting the weight of fuel, fresh water and other reserve items that need to be stored during the voyage from the total deadweight of the ship.
Ship deadweight tonnage can be used for cargo statistics; As the basis for calculating the monthly rent of time charter; Indicates the carrying capacity of the ship; It can also be used as a unit for calculating the cost of new ships and the price of old ships.
What do you think of the ship's design draft dwt 3 waterline?
Look at the reading at the lower edge of the draft number, the word height is 10 cm, and the strokes are 2 cm thick.
For example, the water surface is at the lower edge of reading 4, which is 40cm；; On the upper edge of 4, it is 50 cm; The horizontal lower edge of 4 is 42 cm, and the horizontal upper edge of 4 is 44 cm. Add the meter reading to the front.
When there is a surge, you should observe it for a period of time. You can read it when the water surface is calm, or you can choose the average of the upper and lower peaks and valleys. Bring a strong flashlight at night. If the water surface is calm and illegible, throw a pebble to inspire a water pattern.
Waterline (waterline mark) usually refers to the load line of a ship in summer, which is represented by S (there are two kinds of waterline marks at home and abroad), indicating that the maximum draft depth is between the ship's lifting and the summer area. The marks on the paint on one side of the merchant ship indicate the possible draft of the ship after loading, which usually includes tropical fresh water, fresh water, tropical seawater, summer seawater, winter seawater and winter North Atlantic water.
The load line is usually accompanied by a circle cut in half by a horizontal line. The horizontal line indicates the no-load state in summer, and the letter indicates the name of the classification society (for example, L R indicates Lloyd's Register). The load line was named in memory of Samuel Pumsall (1824- 1898), a British parliamentarian, who devoted himself to promoting the safety of British merchant ships.
Draft, referred to as draft, refers to the deepest length of the sunken part of a ship, and different ships have different drafts. The same ship has different draft according to the different load and salinity of the water area. Large ships will be too deep to enter shallow bays, ports or canals. The hull is engraved with waterline scale to show the draft.