By the end of the 1850s it was clear that France was unable to match British building of steam warships, and to regain the strategic initiative a dramatic change was required.
Ved udgangen af 1850'erne stod det klart at Frankrig ikke var i stand til at matche det britiske byggeprogram for dampdrevne krigsskibe, så for at få det strategiske initiativ tilbage, var der behov for dramatiske ændringer.