Admiral Sir Cyprian Bridge regards the functions of defense by a navy as divisible into three main classifications. He says, "The above-mentioned three divisions are called in common speech, coast defense, colonial defense, and defense of commerce." From this classification we are given a hint as to what a sailor means by "naval supremacy," "freedom of the seas," and other terms so misused that to-day they mean nothing. "Coast defense" means defense against invasion; "colonial defense" means the safeguarding of distant possessions against enemy forces; the "defense of commerce" means such supremacy on the seas as will insure absolute safety of the mercantile marine from enemy commerce-destroyers.
To-day every great nation is waging a trade war. The industrial competition of peace is as keen as the competition of war. All the great Powers realized years ago that, to gain and keep their "place in the sun," it was necessary for them to construct navies that would insure to them a certain control of the seas for the protection of their commerce. In this way began the abnormal naval construction in which the Powers have vied with one another for supremacy.
A simple way of looking at the question, what constitutes the power of a fleet, is to consider the warship as merely a floating gun-platform. Even though this floating platform is the most complex piece of mechanism that was ever contrived by man, nevertheless its general function is simple. The war has given us enough experience to convince us that the backbone of a navy is, after all, the heavily armored ship of moderately high speed, carrying a very heavy armament. This floating gun-platform is the structure best fitted to carry large guns into battle, and to withstand the terrific punishment of the enemy's fire.
The battleship is to-day, notwithstanding the development of other types, queen of the seas. It is therefore not difficult to estimate the relative power of the fleets of different nations. In fact, a purely engineering estimate of this kind can be made, and the respective ranks of the world's naval powers ascertained. Germany has shown all through the war that she thoroughly appreciated the British naval supremacy. Her fleet has ventured little more than sporadic operations from the well-fortified bases behind Heligoland. It was probably the pressure of public opinion, and not the expectation that she would achieve anything of military advantage, that forced her to send her high-sea fleet into conflict with the British squadrons off Jutland.