A similar advantage, though in a modified degree, is that shown as possessed by _A_ in Fig. 5. Due to the direction of movement of the _A_ and _B_ fleets, it is easier for _A's_ torpedoes to reach _B_, than for _B's_ torpedoes to reach _A_. [Illustration: Fig. 5] Positions of advantage are usually gained by superior speed. One of the main reasons for the development of the battle cruiser has been the fact that her high speed and great offensive power enable her to gain positions of advantage and utilize them. The _A_ positions shown in the figures are attainable by battle cruisers against battleships, and are very effective. A procedure analogous to that of flanking is one in which part of a force is attacked when it is separated from the rest of the force, and cannot be supported by it--in that some of the weapons of one force cannot be used. The effect is similar in the two cases, but the events leading up to the two conditions may be quite different. In the former case, that of being flanked, or T'd, the force caught at a disadvantage was together, and was able to operate effectively as one force against a force located in a given direction; but was attacked by a force located in another direction; while in the latter case, the force was divided, and one part was caught, while distant from and entirely unsupported by the other part. The former condition is more likely to result from tactical operations, and the latter from strategical operations--and yet, especially in land operations, the flanking of one force may be brought about by the carefully planned strategical combinations of the other force; and catching one part of the enemy's force unsupported by the other parts may take place during the tactical maneuvers of an actual or a simulated battle. In naval operations, the catching of separated parts of an enemy's force is a more frequent attempt and accomplishment than is that of getting a position where a column of ships can be attacked from ahead or astern. It seldom happens, with the great number of vessels of all kinds which compose a modern fleet, that it is practicable to keep the various parts together, or that it would be desirable to do so. The closest approximation to keeping a large naval force together, is keeping them in column; because in that formation, the ships can be made simply to "follow the leader" without signal, and act like one long, flexible body. But the vessels of a modern fleet would make a column many miles long--a column of 20 battleships alone would be 5 miles long, and the addition of the various cruisers, destroyers, and other vessels, would make a column so long that it would be unwieldy; and if its ends were attacked, the other vessels could not come to their relief. Besides, the duties of battleships, battle cruisers, scouts, destroyers, and submarines, are distinct--with the result that, as in land operations, bodies of the various types operate separately and apart from those of other types.