Why does water leak from holes in the sides of a ship?
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Why does water leak from holes in the sides of a ship?

Many people, looking at powerful dry cargo ships, tankers in the port, probably noticed how water suddenly starts pouring out of them for no apparent reason. And from, apparently, specially made holes. What is this and why?


Some people think that this is how they get rid of water that gets into the holds from the seas and oceans. Some people think that we see the excess after washing the deck. This is partly true, but still far from the truth: the reason for the “ejection” of water over the sides is completely different, and there is more than one.

Ballast


It is necessary for a modern vessel to ensure its stability in storms, maneuverability, increase or decrease draft. If the latter is too large, the ship will not be able to enter some ports. On the other hand, the absence of ballast will lead to the fact that the propeller and rudder of an empty vessel will be above the water surface. Accordingly, it will be difficult to control such a ship.

Until about 1880, when ships with metal hulls became widespread, sand, crushed stone, and stones were used as ballast.

Nowadays, this role is played by seawater: inside a vessel, it can be from several hundred liters to 130 thousand tons or more. The main advantage of such an additional load is the simple ability to increase or get rid of it at any time.

Why does water leak from holes in the sides of a ship?Ballast helped the sailboats to be stable despite the huge area of ​​the propellers. Photo: youtube.com

Ballast control on modern ships is automatic. As soon as the ship tilts, sensors send a signal, pumps are turned on and the water immediately “moves” to the right place to ensure stability. The onboard computer “commands” this rather complex process. Water is pumped into special compartments located between the holds and the sides.

Ballast water discharge into the sea. Photo: youtube.com

Excess ballast is drained, for example, during loading or if the vessel runs aground. Moreover, the water is removed evenly so that the hull does not tilt. There is even a special international convention on ballast. According to it, it must be changed periodically (since 2004) to prevent the spread of harmful microorganisms.

During storms, waves flood the deck with sea water

After all, a ship can travel thousands of miles and dump something with seawater at the destination port (after unloading) that can damage the local ecosystem. Therefore, it is allowed to get rid of such water somewhere far out to sea. For example, if a ship is sailing from Murmansk to Africa, the ballast must be gradually replaced during the route.

Removing moisture from the deck and cleaning the chain


These are a couple of other reasons why we see streams of water coming out of the sides of a ship. Water can accumulate on the deck after it has been washed, or as a result of a heavy rain or storm, when waves can easily "jump" over the side.

Water on the deck during a storm. Photo: youtube.com

First, moisture accumulates in waterways (special gutters), and then drains out by gravity through scuppers (from the Dutch spuiten and gat: “to pour” + “hole”), located above the waterline.

There may be several anchors with chains and all need to be washed. Photo: youtube.com

As for the anchor chain, when the vessel departs, it is pulled into the hawse hole. This is where water is supplied to wash these metal elements.

Large ships have a system specially designed for pumping in seawater.

Lying on the bottom (if for a long time), the chain and anchor "magnetize" microorganisms and dirt. To prevent them from getting into the storage box, everything is washed with overboard liquid.

Engine cooling


Of course, sea water is not suitable for this. But it still performs this function, "working" in the external circuit and cooling the clean liquid that passes directly into the power plant blocks. To ensure a regular decrease in their temperature, the sea water is constantly replaced, draining it when it is very hot.
What do you think about draining water?
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