How long does it take to start and move an aircraft carrier?

Aircraft carriers are today’s navies’ well-deserved maritime hegemons, and a naval force with aircraft carriers is a symbol of the world’s major powers. However, aircraft carrier technology is difficult and costly, and it is currently merely a “town treasure” that only a few world powers can afford to construct and operate. So how long does it take a modern aircraft carrier to start? answer: at the very least, 10 hours!

Modern aircraft carriers are generally divided according to their power unit, nuclear-powered aircraft carriers, and conventionally powered aircraft carriers, but if they are classified according to the engine, they are mainly divided into two categories: steam turbines and gas turbines. Among them, the aircraft carriers of the united states, India (INS Vikramaditya) china, russia, france and other countries use steam turbines, which is the proverbial “Boiling water”, but the united states and france use nuclear reactors to boil water, while china, India and russia use fuel boilers to boil water. In addition, the united kingdom is a different kind, the united kingdom’s “Queen elizabeth” class aircraft carrier uses mt-30 high-power gas turbines, in addition to the united kingdom, India (INS Vikrant) italy, japan’s light aircraft carriers also commonly use gas turbines as power.

Engine compartment of Nimitz class nuclear powered aircraft carrier
Engine compartment of Nimitz class nuclear powered aircraft carrier

If you were to run each type of aircraft carrier with 200,000 horsepower, non-stop for one-week, a conventional carrier (HMS Queen Elizabeth) would require over 5 million liters (1,30,000 gallons) of diesel fuel while a nuclear carrier (USS Gerald R Ford) would require just 4 Kilograms (8.8 pounds) of enriched uranium.

The characteristic of the steam turbine is that it requires a large amount of high temperature and high pressure steam, and then uses these high temperature and high pressure steam to promote the work of the steam turbine, and at the same time use the steam turbine to promote the operation of the ship. Therefore, for aircraft carriers equipped with steam turbines, to start going to sea, they need to first “Boil water”. Take china’s “Liaoning” aircraft carrier as an example, the ship is equipped with 4 tb-12 boilers, a total of about 60 tons of boiler water, so the Liaoning to go to sea, you must first boil the 60 tons of boiler water, and it should be pointed out that the aircraft carrier steam turbine uses “Superheated steam”, that is, the temperature exceeds 100 ° c, the pressure exceeds 1 standard atmospheric pressure of high temperature and high pressure steam. According to the introduction, the steam temperature of the steam turbine of the liaoning aircraft carrier is as high as 400 ° c, so it is not simply “Boiling the water”, but to burn to at least 400 ° c, generating high temperature and high pressure steam to promote the operation of the steam turbine. Limited by the heat of the boiler, it takes 10 hours to boil the 60 tons of boiler water into high-temperature steam at 400 ° c.

HMS Queen Elizabeth engine compartment
HMS Queen Elizabeth engine compartment

In terms of boiling water, nuclear-powered aircraft carriers have certain advantages over conventional aircraft carriers, because even if the nuclear-powered aircraft carrier returns to the port to dock, but the ship’s nuclear reactor never completely shut down, but maintain a low-speed operating state, so as long as the nuclear-powered aircraft carrier is not into the dock for overhaul, the boiler has been kept in a heated state in the case of general port, so the time to boil water before leaving the port is much faster than that of the fuel boiler. according to data released by the u.s. navy, the nimitz-class nuclear-powered aircraft carrier only needs about 4 hours to boil water before leaving the port, which is more than half of the fuel boiler aircraft carrier. Therefore, compared with conventional oil-fired boilers, nuclear power units do have big advantages.

As for the gas turbine, its start-up is faster. Because the ship’s gas turbine itself is improved from the aircraft engine, it only needs to inhale oxygen, ignite the fuel, generate hot air expansion after full combustion and promote the gas turbine to do work, omitting the boiling water link in the middle, which naturally greatly shortens the starting time of the aircraft carrier. However, gas turbines also have their own problems, such as gas turbines have high requirements for fuel, and can only use purified distillate fuel, while oil-fired boilers can adapt to various fuels and even residual oil (in theory, it is also possible for oil-fired boilers to burn chopped wood, but the efficiency of diesel heat is too low). Moreover, the gas turbine has a precise structure, the vulnerability of parts is large, and it is more difficult to maintain, and the cost of use is significantly higher than that of the steam turbine driven by the oil boiler and in particular, nuclear power units still need steam turbines and nuclear reactors to be used together, so steam turbines still have advantages over gas turbines in terms of scope of application.

There are also many friends who may worry that it will take 10 hours to boil water for the steam engine before the aircraft carrier sets sail, in case of an emergency, the aircraft carrier cannot be dispatched, will it not become a target for the enemy? and it’s a dead target. in fact, this kind of worry is not necessary, because the military ports deployed by aircraft carriers are under the close protection of the navies of various countries, and it is difficult for hostile countries to effectively break into important ports defended by the enemy. Secondly, after the aircraft carrier itself is deployed at sea for a period of time, it must return to port for recuperation, so it is difficult for a single aircraft carrier to form a sustained and effective combat effectiveness, and at present, the world’s major powers are generally equipped with more than one aircraft carrier, so that multiple aircraft carriers can be rotated and deployed at any time, and it can be guaranteed that there are aircraft carriers on duty at sea at any time. So the aircraft carrier takes 10 hours to start, which is not a big problem.

The second is Carriers operate on a schedule. They know when they’re going somewhere weeks, sometimes months, in advance. Carriers are ready to go when it’s time – getting underway is a matter of casting off the lines and backing away from the pier.

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