What year marked the end of low-cost naval supremacy for the Royal Navy and the start of a naval arms race?

The year that marked the end of low-cost naval supremacy for the Royal Navy and the beginning of a naval arms race is 1861. This period is significant as it coincided with critical developments in naval technology and military strategy, particularly the emergence of ironclad warships. The introduction of these ironclads made traditional wooden ships obsolete, prompting other nations to invest heavily in naval capabilities and compete with the Royal Navy. This shift in naval warfare dynamics initiated a race among different countries to enhance their fleets and capabilities, changing the landscape of maritime power.

Other dates, such as 1841 and 1835, do not align with the technological advancements and international competition evident by the early 1860s. Similarly, 1873, while relevant in naval history, falls outside the specific timeline that captures the start of the intense naval rearmament and competition that characterized the latter part of the 19th century. The year 1861 is thus pivotal as it signifies the transition from the Royal Navy's uncontested dominance to a more competitive naval environment.