The history of war at sea is replete with instances of a sudden technical advancement in weaponry that transforms the fortunes of a naval power. At some dim twilight in man's past, it was discovered that a ram positioned in the bow of a galley could sink or severely wound an enemy vessel. Thus could one nation dominate the trade routes or impede another power from launching a sea-borne invasion against their territory.
For centuries afterward naval warfare remained static, until the Romans introduced the corvus against the dominant power at sea, the Carthaginians. This was a type of bridge with a spiked end that impaled itself onto an enemy galley, thus allowing Rome to use her predominant land tactics in a sea environment.
Desperate times too often than not forges change at sea. The ancient Byzantines, besieged by land and sea by the burgeoning power of Islam in 674, restored their fortunes by clever use of flame projectors placed on board ship, the famed "Greek Fire". An obscure chemical likely made of naphtha, quicklime, and sulfur that scorched anything it touched, water only increased its lethality. The use of such a volatile liquid made it as much a hazard to the operator as its target, and the practice didn't survive the Middle Ages.
With the rise of Western European nations came a succession of revolutions at sea, first involving land cannons transfered to warships with the addition of sails. Later in the 19th Century, a renewed burst of inventiveness gave us steam power, exploding shells, torpedoes, naval mines, coastal submarines, and ironclad warships. With the 20th came oil and nuclear powered vessels, aircraft carriers, and sea going submarines.
Concerning the fleet submarine, they have become the most under-estimated war craft in each new conflict, often inflicting far greater damage and proving much harder to control than was envisioned by pre-war naval planners. Now that such vessels have equaled in performance surface warships, and even surpassed then in terms of stealth, it will be interesting to observe the next "Battle of the Atlantic".
With each new revolution in weaponry came an equally transformative change in the design of naval ships. Equipped with the ram, war galleys became slim, speedy, and lighter. The largest gun carrying warship, the ship of the line, saw its hull become rounder and heavier, allowing the maximum number of gun ports in its thick wood sides. Steam power spurred the disappearance of masts and rigging, while exploding shells required the placement of ever thicker and more advanced armor plating on the new battleships.
The widespread use of new heavier than air craft on land coincided with the development of naval planes during and after the First World War, and the construction of mobile airfields at sea, or carriers. Torpedoes inspired "David vs. Goliath" plans by naval strategists, and gave us torpedo boats and destroyers, while increasing the lethality of the submarine.