The real technological edge enjoyed by the West in this period was naval. There was no real equivalent in the non-Western world to Europe's naval superiority, which bestowed at least three advantages on the invaders. The first was power projection. If Europe discovered the world from the fifteenth century, and not vice versa, it was because the capability in the form of well-built ships had married the motivation to sail forth and conquer. Navies gave the West strategic reach, a means of passage to the most distant corners of the earth opposed only by the caprice of nature and the ships of rival European navies. As A.T. Mahan noted in The Influence of Sea Power Upon History, 'if Britain could be declared the winner in the imperial race, the credit, or blame, resided with the superiority of the Royal Navy'. A second benefit of naval superiority for imperialists was security: In the early days when Europeans were on the defensive on land, especially in Africa and the East, they seized coastal enclaves, often islands like Goa, St Louis de Senegal, Hong Kong or Singapore, which they could defend and supply by sea. Precarious frontier posts like Montreal might have succumbed to Amerindian constriction had their communications depended exclusively on overland routes.
Finally, sea power meant operational and even tactical mobility, which could translate into strategic advantage. Sea power was the force multiplier for the British. The British ability to shift their troops up and down the coast in India was an important element in their victory over the French there. In 1762, British maritime expeditions sent to punish Spain for her alliance with France in the Seven Years War seized both Manila and Havana. In North America, the Royal Navy gave Britain the decisive edge over France, a country with three times the population and ten times the army: Maritime expeditions swept up French settlements around the Bay of Fundy in 1710, captured Louisbourg in 1745 (and again in 1758), and imposed a blockade which, by stemming the supply of gunpowder, munitions and muskets, began the unravelling of France's Amerindian alliances as far inland as the Great Lakes, the Ohio Valley and Louisiana. A seaborne strike in 1759, behind a screen of men-of-war blockading French ports, allowed Britain to pierce the heart of New France at Quebec, rescuing what, until then, had been a fumbling campaign of attrition against the southern glacis of French Canada. And although the French Navy - La Royale returned the favour twenty-two years later at Yorktown, sea power had made land operations against New France a leisurely march to a foregone conclusion. British maritime expeditions had harvested so many islands of the French Antilles by 1762 that British diplomats attempting to negotiate a peace were embarrassed by their nation's military success. British sea power forced Napoleon to abandon the reconquest of Saint Domingue (Haiti) in 1803.
Dominance of the Pacific was essential for the victory of the rebellious South American colonies, who promoted Lord Cochrane, a disgraced Scottish aristocrat, to the rank of admiral, and launched a successful amphibious assault on Lima, an oasis in the desert, from Valparaiso in Chile in 1820. Foreign corsairs organized a small fleet to assault Spanish ships in the Caribbean.
Brown-water operations were also a feature of imperial warfare. Lake Champlain and the Richelieu river provided a classic invasion route into and out of New France. During the Second Seminole War, the United States Navy operated steamboats on the larger rivers while oared, flat-bottomed Mackinaw boats, capable of carrying twenty, moved men along the tributaries. This permitted American troops and volunteers to re-establish their presence in central Florida, abandoned to the Seminole chief Osceola in 1835. Without the support of the Russian navy, the string of posts along the Black Sea created to sever supplies from Turkey to Shamil would undoubtedly have fallen to Murid attacks. Following the Crimean War, these maritime outposts served as bases of operations against the Cherkess population of the western Caucasus. British victory in the Opium War with China (1839-42) demonstrated how relatively small naval forces could impose their will even on a vast continental empire. Sea power allowed the British to transform what the imperial court in Beijing viewed as a distant dispute in Canton into a struggle which directly threatened the economic health and political stability of the empire itself. Junks and poorly defended Chinese coastal fortifications offered scant defence against twenty-five Royal Navy ships of the line, fourteen steamers, and nine support vessels carrying 10,000 troops. With this relatively small force, the British seized four important coastal trading centres, sailed up the Yangtze River to block the Grand Canal which carried much of the Celestial Empire's north-south commercial traffic, and threatened Nanking. This was enough to bring the Chinese to the peace table. However, in 1884-5 the French were far less successful in employing their navy to wring concessions from the Chinese when they attacked Formosa which, clearly, Beijing did not believe vital to its interests. The creation of a gunboat force was critical in allowing the Celestial Empire to defeat the Taiping and Nien rebellions, sparked by European encroachment, in the 1860s. Naval artillery made the walled cities held by the Taipings along the Yangtze untenable. Gun sampans and eventually gunboats on the Yellow river and Grand Canal escorted grain convoys, and linked a defensive chain of fortifications created to keep Nien forces from breaking out across the Yellow river, much as the British in the Boer War of 1899-1902 used railways to link barriers of blockhouses built to contain Boer commandos. The French pioneered river flotillas to advance up the Senegal River toward the Niger from the 1850s.