The aircraft carrier deck is too short to allow the hunter aircraft to reach the climb speed alone. Therefore, special steam catapults are used for their acceleration. The system will soon be replaced by a much more modern and functional solution called EMALS (Electromagnetic Aircraft Launch System), which is an electromagnetic catapult.
Navy on board aircraft carrier Gerald R. Ford has just conducted the first official test of new technology, which you can see in the film below. During the test, however, the fighter was not used because it did not want to damage the tens of millions of dollars of the machine. It was replaced by about 40 tons of weight on wheels, corresponding to the mass of the aircraft.
EMALS is a system much more efficient than a steam catapult. First and foremost, much smoother acceleration is achieved, which results in lower engine forces. In addition, you can more accurately adjust the speed of such a catapult, which allows you to shoot different types of aircraft.