These standards were designed to achieve an optimal balance between cost, maneuverability, and firepower, to maintain a competitive edge against the English navy, which possessed a significantly larger number of ships.

[9] It was incorporated into a modest squadron of six ships and three frigates under the direction of Lieutenant General Macnemara, whose responsibility was to provide security for 18 vessels transporting reinforcements to Canada, under the command of Dubois de La Motte.

[10] With Macnemara falling ill and resigning, Inflexible remained under the same command but was reassigned to Du Gay, who patrolled the waters near Brest to safeguard incoming trade convoys.

Like other vessels, it was affected by the severe typhus epidemic that devastated the crews and spread to Brest upon its arrival in November, resulting in the deaths of thousands in the city.

[12] As was the case with the majority of the Brest fleet, Inflexible remained docked in 1758 to reorganize its crew, which had been disordered by the epidemic of the previous year, and of preparing for the 1759 campaign, which the government hoped would prove decisive, given that a landing in England was planned.

[14] Inflexible was mobilized under the command of Chevalier de Caumont to serve in the rear guard of the 21-ship squadron under Conflans, which was tasked with escorting the invasion fleet.

To evade an assault by the Navy's fireships, Inflexible was stripped of its artillery and heavy equipment, thereby enabling it to navigate as far upstream in the Vilaine estuary as possible.