You might wonder at times if massive things like cruise ships tip over and if not, then why not? It is okay to be anxious if you are about to go on a cruise or merely curious as to how this remarkable phenomenon works. Since I have been in the same boat (ironic?), so I dug into the matter a bit and came up with all the answers you might be looking for!
Cruise ships can float on the surface of the water is due to buoyancy, I think we all know this Now the question arises as to how this balance is maintained and what thought goes into constructing a ship that keeps it from tipping over.
To get elaborate explanations for this result of scientific research, continue reading the article!
How Do Heavy Cruise Ships Float On Water?
You must have witnessed in movies or real life if you have traveled on a cruise ship that very little part of the boat is below the waterline, whereas a great height of it is above it. And the cruise ship is still able to remain stable despite the large and rough waves that usually accompany its voyage. Amazing, right?
But the question of ‘how?’ always crosses my mind and which is why I did a little research of my own as to how this phenomenon of floating works!
A cruise ship experiences a variety of forces acting on it. The two most important ones are the weight which is pulling it downwards, and the buoyancy, which is pushing it upwards.
If the weight gets greater than buoyancy, the ship will eventually sink. If both are equal and opposite, half of the ship will be underwater and half over it, but if buoyancy is greater than weight, the ship will stay upright above water with a small part of its body beneath it.
The amount of these forces and the sites where they act are crucial for the ship to remain upright and stable.
The Force of Gravity
The force of the ship’s weight is equal to the force of gravity. And the exact site where the force of gravity acts is called the center of gravity. Now this ‘center’ of gravity is not just a central mark that you can pinpoint. It is a relative point that is determined based on the weight of everything that is on the ship. In simple words, it is the point where the weight of the entire ship, along with its constituents, is concentrated.
If the weight of all the constituents is pretty much the same or is distributed evenly, this point will be exactly in the middle. But this is not how it is in cruise ships because of the heavy machinery, waste tanks, cargo, and engines which are kept at the bottom, whereas the lighter spaces like theatres, rooms, halls which have greater movement and flow of air are at the top.
Because of this uneven distribution, the center of gravity is pushed downwards, creating a low center of gravity (discussed in detail below).
The more an object sits in the water, the lesser is its chance to topple over. This is the rule that is followed to ensure the safety and stability of cruise ships.
But won’t the weight of the ship caused it to sink? Continue reading the next part to find out how does it remain buoyant.
The Force of Buoyancy
Coming to the second most important force that acts upwards on the ship, keeping it from sinking is buoyancy. This force is provided by the water underneath, and it opposes the force of gravity and/or weight of the ship. As I mentioned about the principle of center of gravity, the center of buoyancy is also the point right in the middle of the ship’s body which is present in water.
If the ship’s weight (density) is greater than water, it is going to sink. If it is not, it will keep floating over it because of the considerable upward force of the water. This upward force is provided by the water, which was displaced by the weight of the ship in the first place.
This balance between the two forces is very important to maintain. Now that you know the basic principle of floating let’s move on to how this basic knowledge helps cruise ships to stay upright!
How Do Cruise Ships Manage to Stay Upright?
You would think that the center of gravity right in the middle of the ship is ideal since the weights are evenly distributed. Let me break this to you; it is not!
Having a center of gravity right in the middle does not account for the external factors that act on the ship, like the wind or waves in water. In such a scenario, if the ship is hit by strong winds or rough waves, it is going to topple over to one side! This is so because the center of gravity is in the middle and not weighing the ship down (is not indirectly providing it resistance!)
For the cruise ships to remain upright in the water despite crazy sea situations, the center of gravity should actually be dragged downwards (as I discussed earlier – by the presence of heavy equipment down there). This is known as the ‘low center of gravity.
Moreover, this concept is facilitated by the design of these large ships too. The rounded base keeps the drag in water minimum, ensuring the ship’s stability which means an effortless journey through the water without swaying to either side if hit by strong winds.
It also prevents the passengers from feeling seasick too by avoiding excessive rocking. These features make the large, heavy cruise ships quite buoyant to float in water without the risks of tipping over.
Other Features that Contribute to Cruise Ship’s Stability
In addition to keeping the heavy equipment like fuel stores, huge engines, cargo, and others at the bottom of the ship, additional features like ballast tanks are employed to facilitate the boat in staying upright.
By pumping water and fuel throughout the base of the ship, from one side to the other, these tanks ensure the equilibrium of the ship in rough seas by assisting in controlling and stabilizing it whenever required, thus contributing to keeping the center of gravity as low as possible.
This is supplemented by the wide and round design of the hull of the ship, which enhances its resilience. It is also stated that the material of the hull, which is supposed to remain beneath the water, is sturdier and heavier than the one used at the top, accounting for the increased weight at the bottom of the ship, which supports the low center of gravity.
Rough sea waves and strong winds are sometimes quite unexpected. Even though the cruise ships are constructed keeping all the possible threats and dangers in mind, certain severe weather and sea conditions like rogue waves can compromise the stability of these large vessels.
To prevent undesirable occurrences and extreme weather and sea conditions, weather routing services are also provided so that you don’t take a potentially endangering route.
With every passing day, nature’s rules and principles are being implemented in the manufacture of the latest technology and products. It has helped all of us in managing challenging tasks and has made life considerably easy for everyone.
One example is the glorious cruise ship remaining upright even in the roughest of seas and crazy weather situations. Its breakthroughs in science have enabled safe and secure trips on unpredictable entities like oceans and seas by keeping engineering principles in mind.
The combined effect of the buoyancy of these ships, their low center of gravity as well as the additional features like the shape of its hull, the weight distribution in a well-thought design, with the use of ballast tanks keeps these enormous ‘floating cities’ stay afloat and complete safe trips!