Arizona republican., 1892-06-21
HARBOR DEFENSES.
PLANTING DEADLY EXPLOSIVES TO
 PROTECT THE COAST.

What a Vast Amount of Labor, skill.
 Time and Money Is Needed to Com l pIeto Thorough System of Coast De- l fense-Advantages of the Torpedo.
 There is very widely diffused idea among people who have not made a | special study of the subject that torpe- does, and torpedoes alone, can defend any harbor against hostile attack. | The destructive effects of few tor pedo explosions under the most favor 1 able circumstances have caused this l branch of warfare to assume an undue importance, an importance wholly un- warranted by the results and created by generalizations from isolated instances, entirely without regard to the natural limitations of the efficiency of any tor pedo system, however perfect.
 1t is the object of this article to en- deavor to show the actual capabilities of torpedoes, the results attainable by their use, and the restrictions inevitably at tending their indefinite expansion into complete system of defense.
 Great guns must play an important part in all harbor defense, but for the proper and adequate defending of navi- gable chennels bouyant mines, exploded by contact, are the mainstays.
 With their use, however, host of per plexing conditions arise, the twisting and wearing of the cables and moorings, the depression due to the currents, the danger of sympathetic explosions, the leaking of the cases, the obstruction of the channel for friendly nayigation-all these have to be overcome as best they may be.
 Where port has several navigable channels, and it is practicable to sacri- flee one or more, their closure by means of self acting torpedOes is easy.
 Where a channel, however, cannot be entirely abandoned, self acting mines are useless, for in order to be thorough ly reliable they must be as dangerous to d friend as to an enemy. Furthermore, their planting, and much more, their re- is to be accomplished only at great risk The limited applicability of ground mines is well known. Torpedo science furnishes two other types for harbo de. fense; the buOyant mine and the dirig- ible torpedo, although the latter proper ly forms distinct class
 Great nicety in planting torpedoes cannot be expected, and this fact, cOu- pied with the inevitable shifting of the mines from various causes, leads direct ly to the conclusion that a great num- Der of mines must be relied upon rather than precision in their manipulation.
 Despite the number of mines, vessel attempting to pass the lines may still fail to strike a mine hard enough to work the circuit closer. To meet this contingency perfect torpedo system must provide means for firing the mines at will in groups of three or four. It will always be possible to accurately To- cate vessel within a dangerous space of this number of mines, and their simul- taneous explosion will have the desired effect
 To furnish a passage for the electric current many cables are needed, and to avoid confusion some regular method of planting must be adopted. It is con- venient to plant the torpedoes in groups capable of being fired by judgment, these groups constituting the units, which arc combined into the larger unit whose limit is generally the number of mines that can be operated through single seven core cable
 The grand groups thus formed are ar- ranged in lines, tho latter radiating in such a manner from the operating case ments that the separate units can be easily located by triangulation. The intervals between the lines are filled with skir1nish lines-single mines strung on single conductor cable and exploding by contact only,
 Many forms of movable torpedoes for harbOr defense have been tried in differ ent countries with varying degrees of success. For accuracy of direction and range of destructive power the Sims Ed ison fish torpedo is perhaps unexcelled Extended trials at Willet's point have satisfactorily demonstrated it's ability to carry 200 pounds of dynamite to a dls- tance of two miles at speed of about twenty miles per hour. The charge is exploded upon contact with the vessel or by the action of the operator on shore.
 The dirigibility of the torpedo is per feet, It follows its prey as though endowed with life, swerving to the right | or left as necessary, diving under booms or other Instructions, cutting through l nets, and never slackening its great speed until the end of it's cable is reached, At present a two mile radius is deemed sufficient, although this could be increased if necessary by enlarging the fish" itself. Accommodation