This is a fleet I played on vassal back in 2017, its based on a default fleet I play in real life (I like playing fleets I actually have the cards for).
It is a mixed fleet with a dedicated gunship (La Bonne Chance), dedicated treasure hunter (La Vengeance) and support ship for either (Le Courageux).
La Bonne Chance works well as a gunship with its solid movement, cannons and ability.
La Vengeance works for treasure running simply because it can hold 4 treasure and has a good movement. I do wish I had a cheaper french ship for treasure hunter but it works quite well as is.
Le Courageux is in the middle of the two it is not as combat effective as La Bonne Chance or can carry as much as La Vengeance but its middle stats allow it to support either depending on what is needed.
All in all I think this is a solid fleet that can do well in casual 40 point games.