Charmes built commerce-raider survival around guns and speed

Gabriel Charmes framed his 1886 reform program around fast commerce-raiding cruisers. By calling his book Reform of the Navy, he presented the existing service as a system in need of repair and his preferred spending program as the remedy. The proposed cruisers' 138.6 mm guns were considered sufficient for destroying merchant ships, while a planned 20-knot speed was supposed to let them avoid anything more powerful. The unusually exact 138.6 mm caliber raises the question of why it was preferred to a more obvious rounded size. A ship that depends on speed for protection must remain faster than every opponent throughout its service life. The Forbin requirement therefore depended on an advantage that advancing machinery could rapidly erase.