How ships with their remarkable sizes and weight manage to float is one of the wonders of science.
Some ships come in sizes of up to 300 meters and with weight of more than 250,000 tonnes.
To put that into context, there are ships with a length equivalent to that of two standard football pitches combined or even more.
So how and where are the ships constructed and launched into the various waterways?
For starters, ships are assembled in specialized facilities called shipyards which are usually in strategic locations close to waterways.
The process of assembling ships can be lengthy and takes place in phases.
However, after completion, the ships are launched in water where they are designed to operate in ways dependent on size or facilities available.
Lifting
One way of launching a ship or water vessels in general is through lifting. This is applicable for small ships or boats.
It entails using mechanical devices including a crane to place the vessel into the water.
However, this method of launching is limited as it is impossible to lift very large cruise ships for example.
Airbag ship launching
The use of airbags is also common in naval engineering, which refers to the technology of building and assembling ships.
Airbags are continually becoming common in ship launching owing to their benefits.
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During the assembling process, the vessel is supported by support blocks which keeps them stable throughout the process. The airbag launching method entails inflating airbags and placing them beneath the ship.
As the bags inflate, the ship is jacked upward away from the supporters’ surface. Subsequently, the support blocks are removed leaving the ship’s weight and length distributed on the airbags.
With the requisite pressure, the ship is cut loose to roll on the rubber tubes towards the water. However, the ship has to be supported with ropes while rolling towards the water.
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The airbag and lifting have one aspect in common, that they cannot be used in launching large ships including most cruise ships as their capacity is only limited to light vessels.
Gravitation launching method
The gravitational method is also common in launching ships. This method can either use an oiled slideway, a roller slideway, or side oiled slideway.
While using the oiled slideway, the ship is placed on an oiled rail to help it slide on its way towards the water.
The method is one of the oldest and is preferred due to the simplicity of equipment used. However, the oil used on the slideway is a major pollutant of water making it a challenge in modern and sustainable naval engineering.
Like the name suggests, the techniques use the oil or any other lubricant material to help the vessel slide into the water from the point of assembly.
Floating-out method
The Floating Out Launching method is one where the manufacturers fill the docks with water to facilitate the ship’s movement into the water.
Initially, the ship is manufactured in dry docks until completion when the docks are filled. Despite concerns of high investment capital, the method is known to be efficient and safer compared to the others.
