Is the 3-meter waterline filled with stuff?

The waterline of 3 meters is loaded with things

The waterline indicates the depth of the ship submerged in the water. Many horizontal horizontal lines are painted with paint next to the ship to indicate the depth of the ship at different loads. Draft. The highest waterline indicates the maximum safe load capacity.

The "waterline" is the standard for ships to load cargo in fresh water. Below the "waterline" of the ship, you need to look at four very short horizontal lines. The first line is the "Indian Ocean Line", the second is the "Summer Ocean Line", the third is the "Winter Ocean Line", and the bottom one is the "North Atlantic Winter Line".

These four lines respectively represent the "draft" limit of the ship in different seasons and in various oceans when the ship is fully loaded with cargo. Can you tell me why in different seasons and in different oceans, the "draft" limit of a ship is different? Analysis: A ship is floating on the water with enough cargo. Since the gravity does not change, the buoyancy force on the ship in any sea area should also remain unchanged. Since the density of seawater in different sea areas is different in different seasons, the "draft" depth will also be different.

Answer In summer, the temperature of sea water increases and its volume expands. Density decreases. In winter, the temperature of sea water decreases, the volume shrinks, and the density increases. Therefore, a ship with sufficient cargo will have a deeper "draft" in sea water with high temperature in summer, and a shallower "draft" in sea water with low temperature in winter. In the same way, in different oceans, the amount of salt in the seawater is different. In the North Atlantic, which contains more salt, the seawater is denser, so the "draft" is shallower. In seawater with less salt, " "Draft" is deeper.