Premise: HMS "Achille" was a 74-gun third-rate ship of the line of the Royal Navy. She was built by Cleverley Bros., a private shipyard at Gravesend, and launched on 16 April 1798. Her design was based on the lines of the captured French ship "Pompée" . She was the fourth Royal Navy ship to be named after the Greek hero Achilles in the French style.
Hypothesis: HMS "Achille" was first launched in the spring.