Equal submarine tonnage meets unequal geography

A nominally equal allowance might fund roughly seventy British S-class boats, yet Britain would have to distribute them across the Atlantic, Mediterranean, Indian Ocean, and Pacific. The S class shows how a relatively small coastal boat could turn treaty tonnage into many hulls on paper. The United States needed larger, long-range Pacific boats, while Japan faced its own island-defense and reconnaissance requirements. Those larger boats consumed the allowance faster because range itself required more displacement. Hull count and total tonnage therefore mean little without geography, basing, and mission. The discussion also cautions against treating Winston Churchill's views as the definition of British strategic needs through much of the 1920s and 1930s.