How much would the sea level fall if there were no more ships in the water?

 Accordingly, there are 10,377 ships in all the world's armies, 53,732 ships in all the world's merchant fleets, approximately 4.6 million fishing boats worldwide, and roughly 30 million recreational vessels. This therefore amounts to approximately 35 million ships of all classes.

The largest ship ever built in the world was the Seawise Giant , which displaces 657,019 tons.

If the 35 million ships on Earth were that large, they would displace about 23 gigatons (23 x 10e⁹). In contrast, all the water in Earth's oceans weighs on the order of 1.4 exatons (1.4 x 10e¹⁸). That's a difference of 9 orders of magnitude.

The weight of 23 gigatons, therefore, translates well to a volume of 23 cubic kilometers. The area of ​​Earth's oceans is 361.9 million square kilometers. If we spread those 23 cubic kilometers over the total area of ​​the oceans (23/361,900,000), we find that the ocean would shrink by about 0.064 millimeters (approximately the thickness of a sheet of paper).

Where do cruise ships get their water from and how do they store it?

 Cruise ships get their water from two main sources: the sea and the port. Cruise ships have advanced water treatment systems onboard that can convert seawater into freshwater. These systems use either reverse osmosis or evaporation to remove the salt and other impurities from the seawater.

Cruise ships also get their water from the port when they dock or anchor near the shore. They can connect to the local water supply and fill up their water tanks with fresh water. Cruise ships store their water in large tanks that are usually located in the hull of the ship.

The tanks are made of stainless steel or plastic, which can prevent corrosion and contamination. The tanks hold millions of liters of water, depending on the size and capacity of the ship. The water is then distributed to different parts of the ship through pipes and pumps. The water is also treated and disinfected before it reaches the end user, using methods such as chlorination, ozonation, UV radiation, etc.

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