Although platforms for take-offs and landings had been fitted to warships as early as 1910, the first ship with a runway running the full length of its deck was HMS Argus, launched in 1918. When construction of Argus began in 1914 she was intended to be a passenger liner, but in 1916 the incomplete vessel was bought by the British Royal Navy and completed as an aircraft carrier, with a flight deck 172 m (565 ft) long and space for 20 aircraft. She had a top speed of 20 knots.