Load line and draft sign map, the load line of the ship is drawn in the center of the ship on the left and right sides of the ship's side, indicating the boundary of the ship entering the water. Draught marks are painted on the left and right chords of the bow, the middle and the tail of the hull, with a total of six * * *. Let's look at the load line and the draft sign.

Starting point of load line and draft sign map 1

As early as 1774, Lloyd's Register announced the maximum inflow of ships and kept it for 60 years. /kloc-in the 0 th and 9 th centuries, cargo ships often sank because of reckless overloading, and the crew were buried at the bottom of the sea. 1875, in order to prevent this tragedy from happening again and again, Plimsoll, a British parliamentarian, proposed that all hulls should be marked with load lines to show whether the ships are overloaded. Later, this load line was named Plimsoll line, which is still in use today.

In order to ensure the navigation safety of ships, maintain certain navigation performance in the case of average loss, and make ships have as large load capacity as possible, the International Maritime Organization has formulated the International Convention on Load Lines of Ships in International Navigation 1966, including the later Protocol 1988 and related amendments. The above convention stipulates that load line marks must be drawn on both sides of the ship to limit the maximum draft of water when the ship is fully loaded. Let me share with you the knowledge about the load line.

Load line composition

And its importance.

The load line sign is used to indicate the position of the ship's load line and check the loading status to make it not lower than the approved minimum freeboard. The load line sign consists of three parts, namely, a circle, a straight line intersecting it and letters on both sides. The center of the circle is located in the ship, and the distance from the center to the deck line is the freeboard of the highest navigation area.

As one of the reference stability standards, the load line ensures the basic safe navigation of the water area during the navigation of the ship, and plays a decisive role in dividing the navigation area of the ship and determining the cargo weight of the ship. The correct use of the load line mark can determine the freeboard of the ship, limit the load capacity of the ship and ensure that the ship has sufficient reserve buoyancy.

Inland load line sign

The meanings of each letter symbol in the inland river load line sign are as follows:

ZC- local ship inspection;

CS- China Classification Society;

A —— load line of Class A navigation area;

B —— load line of Class B navigation area;

C —— load line of Class C navigation area;

J1-j1segment load line;

J2——J2-class segment load line;

Load line sign of domestic navigation seagoing ships

The meanings of each letter symbol in the load line sign of domestic seagoing ships are as follows:

ZC- local ship inspection;

CS- China Classification Society;

X- summer load line;

R- tropical load line;

Q—— fresh water load line in summer;

Rq- tropical fresh water load line;

China coast north of Shantou:

Tropical: April 16 to1October 31;

Summer: from 1 1 in October to1in April.

China coast south of Shantou:

Tropical: February 16 to1October 31;

Summer: from 1 1 in October to1in February.

Load line and draft sign Figure 2 What do you think of the draft scale of this ship?

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.

Load line and draft sign Figure 3 The load line of the ship refers to the waterline of the ship when it is fully loaded. It is a sign drawn in the center of the ship on the left and right sides of the ship's rail, indicating the boundary of the ship entering the water. Classification societies or ship inspection bureaus shall make load line marks according to the material structure, ship type, seaworthiness, anti-sinking and other factors of the ship, as well as the regional and seasonal changes of the ship's navigation. This move is to ensure the safety of sailing ships, property carried on board and people. It has been recognized by governments all over the world, and violators will be punished by law.

Load line marks include: deck line, load line disk surface and various load lines related to the disk surface. The meaning of each load line in the figure is as follows:

1, TF (tropical freshwater load line) means tropical freshwater load line, that is, the total load of ships sailing in tropical freshwater shall not exceed this line.

2.f (fresh water load line) refers to the fresh water load line, that is, when the ship is sailing in fresh water, the total load shall not exceed this line.

3.t (tropical load line) refers to the tropical seawater load line, that is, when a ship sails in the tropical area, the total load shall not exceed this line.

4.s (summer load line) means the sea water load line in summer, that is, the total load of the ship shall not exceed this line when sailing in summer.

5.w (winter load line) means the winter seawater load line, that is, the total load of the ship shall not exceed this line when sailing in winter.

6.WNA (Winter North Atlantic Load Line) refers to the North Atlantic Winter Load Line, that is, when a ship with a length less than100.5m sails through the North Atlantic (north of 36 degrees north latitude) in winter, its total load shall not exceed this line.

Marked with l is the wood load line. China Ship Inspection Bureau uses the first letter of Chinese Pinyin as the symbol of the above load line. That is, RQ, q, r, x, d and BDD replace TF, f, t, s, w and WNA. In chartering business, the rent for time chartering is customarily calculated according to the load capacity of the ship in summer.