Great Britain's foreign agreements, already noted, had as a primary aim the concentration of her fleet in home waters. Naval predominance in the Far East she turned over to Japan; in the western Atlantic, to the United States (at least by acceptance of the Monroe Doctrine and surrender of treaty rights to share in the construction of the Panama Canal); and in the Mediterranean, to France, though England still kept a strong cruiser force in this field. The old policy of showing the flag all over the world was abandoned, 160 old ships were sent to the scrap heap as unable "either to fight or to run away," and 88% of the fleet was concentrated at home, so quietly that it "was found out only by accident by Admiral Mahan."[1]
[Footnote 1: Admiral Fisher, Memories, p. 185.]
These and other changes were carried out under the energetic régime of Admiral Fisher, First Sea Lord from 1904 to 1910. The British Dreadnought of 1906, completed in 10 months, and the battle cruisers of 1908—Indefatigable, Invincible and Indomitable—came as an unpleasant surprise to Germany, necessitating construction of similar types and enlargement of the Kiel Canal. Reforms in naval gunnery urged by Admiral Sir Percy Scott were taken up, and plans were made for new bases in the Humber, in the Forth at Rosyth, and in the Orkneys, necessitated by the shift of front from the Channel to the North Sea. But against the technical skill, painstaking organization, and definitely aggressive purpose of Germany, even more radical measures were needed to put the tradition-ridden British navy in readiness for war.
Naval preparedness was vital, for the conflict was fundamentally, like the Napoleonic Wars, a struggle between land power predominant on the Continent and naval power supreme on the seas. As compared with France in the earlier struggle, Germany was more dependent on foreign commerce, and in a long war would feel more keenly the pressure of blockade. On the other hand, while the naval preponderance of England and her allies was probably greater than 100 years before, England had to throw larger armies into the field and more of her shipping into naval service, and found her commerce not augmented but cut down.
Indeed, Germany was not without advantage in the naval war. As she fully expected, her direct sea trade was soon shut off, and her shipping was driven to cover or destroyed. But Germany was perhaps 80% self-supporting, was well supplied with minerals and munitions, and could count on trade through neutral states on her frontiers. Her shallow, well-protected North Sea coast-line gave her immunity from naval attack and opportunity to choose the moment in which to throw her utmost strength into a sortie. So long as her fleet remained intact, it controlled the Baltic by virtue of an interior line through the Kiel Canal, thus providing a strangle hold on Russia and free access to northern neutrals. Only by dangerous division of forces, or by leaving the road to England and the Atlantic open, could the British fleet enter the Baltic Sea. England it is true had a superior navy (perhaps less superior than was commonly thought), and a position of singular advantage between Germany and the overseas world. But for her the maintenance of naval superiority was absolutely essential. An effective interference with her sea communications would quickly put her out of the war.
The importance (for Germany as well as for England) of preserving their main fighting fleets, may explain the wariness with which they were employed. Instead of risking them desperately, both sides turned to commerce warfare—the Western Powers resorting to blockade and the Germans to submarines. Each of these forms of warfare played a highly important part in the war, and the submarine campaign in particular, calling for new methods and new instruments, seems almost to have monopolized the naval genius and energies of the two groups of belligerents. It may be noted, however, that but for the cover given by the High Seas Fleet, the submarine campaign could hardly have been undertaken; and but for the Grand Fleet, it would have been unnecessary.
The naval strength of the various belligerents in July, 1914, appears in the table on the following page.[1]
[Footnote 1: From table prepared by U. S. Office of Naval Intelligence, July 1, 1916.]
| Great Britain | Ger- many | U.S. (1916) | France | Japan | Russia | Italy | Austria | |
| Dreadnoughts | 20 | 13 | 12 | 4 | 2 | .. | 3 | 3 |
| Pre-dreadn'ts | 40 | 20 | 21 | 18 | 13 | 7 | 8 | 6 |
| Battle Cruisers | 9 | 4 | .. | .. | 2 | .. | .. | .. |
| Armored Cr's | 34 | 9 | 10 | 20 | 13 | 6 | 9 | 2 |
| Cruisers | 74 | 41 | 14 | 9 | 13 | 9 | 6 | 5 |
| Destroyers | 167 | 130 | 54 | 84 | 50 | 91 | 36 | 18 |
| Submarines | 78 | 30 | 44 | 64 | 13 | 30 | 19 | 6 |
Owing to new construction, these figures underwent rapid change. Thus England added 4 dreadnoughts (2 built for Turkey) in August, 1914; the battle cruiser Tiger in November; the dreadnought Canada and 5 Queen Elizabeths in 1915; and 5 Royal Sovereigns in 1915-1916. In comparisons, full account is not always taken of the naval support of England's allies; it is true, however, that the necessity of protecting coasts, troop convoys, and commerce prevented her from throwing her full strength into the North Sea. Her capital ships were in two main divisions—the 1st or Grand Fleet in the Orkneys, and the 2d fleet, consisting at first of 16 pre-dreadnoughts, in the Channel. Admiral Jellico[1] gives the strength of the Grand Fleet and the German High Seas Fleet, on August 4, 1914, as follows: