In order for ships to travel across the open sea, they must withstand a huge load: the weight of the ship along with the crew, baggage, accessories and passengers. The secret to why ships do not sink is that they do this with a little help from the principles of density and buoyancy.
Interestingly, cruise ships can weigh from 65 to 70 thousand tons. They displace an equivalent amount of water when they press on the ocean, which meanwhile pushes and holds the ship afloat. That’s why ships don’t sink.
It is for this reason that engineers, speaking of the severity of the ship, mention movement, not weight. In order not to drown, the cruise ship must displace its weight in the water before it sinks into the water. From a technical point of view, it is more difficult to construct such a cruise ship, which will be less dense than the water under it.
To understand why iron ships do not sink, it is easier with the following example: you need to imagine the difference between dropping a bowling ball into water and trying to submerge an inflatable ball in water. A bowling ball cannot displace enough water before it sinks, so it drops. The beach ball does the opposite and stays afloat.
Elementary physics: why the ship does not sink
Engineers help ships achieve buoyancy by choosing light, durable materials and dispersing the weight of the ship throughout the hull. The hull of the ship under the main deck, as a rule, is very wide and has a deep baseline, or the so-called lower part. Large vessels such as cargo, sea, transport, and cruise ships typically use pressure hulls or hulls that divert water to the side to stay afloat. This is the whole answer to the question of why metal ships do not sink.
The shape of the body is the key to success
The round bottom movement case looks like a large rectangle with rounded edges to dissipate resistance or force acting against a moving object. Rounded edges minimize the force of water against the hull, allowing large heavy ships to move smoothly.
If you somehow pulled a cruise ship out of the water and looked at it a few hundred meters, the hull would look like a huge capital letter “U” depending on the size of the keel. The keel runs from bow to stern and acts like the backbone of a ship.
On the shortcomings of the common form of the case
Like everything that happens in our lives, round-bottom hulls have their advantages and disadvantages. Unlike a boat with a V-shaped hull, which picks up waves from the water, the round bottom allows the ship to move smoothly through the water, making such vehicles extremely stable and seaworthy. Passengers on these ships rarely feel any rocking or sideways movement.
Boats with round hulls move smoothly, but water resistance makes them extremely slow. They can sail fast only if a high power engine is added to them. Nevertheless, the need for stability and smoothness exceeds overall speed, which makes the hull with a round bottom suitable for cruise ships.
Protective case
It is worth noting that the hull of the ship is not only the answer to the question why the ships do not sink: the hull, among other things, performs a stabilizing and protective function. Reefs, sandbanks and icebergs can tear fiberglass, composite materials and even steel. To prevent catastrophic damage, shipbuilders usually build cruise ships using heavy-duty steel and insert double hulls as an extra precaution. The dual-casing design is a casing inside the casing, for example a tire with an inner tube.
Unfortunately, accidents cannot be avoided. To prevent ships from crashing if something penetrates the first two lines of defense, vertical waterproof dividers, known as bulkheads, are installed throughout the inside of the hull. These dividers keep damaged ships afloat, stopping incoming water in special compartments, thereby preventing flooding of the entire vessel. Thus, the whole secret of why the ship does not sink even when damaged is the development by engineers of the correct hull.