MECHANICS AND USEFUL ARTS. 77 



efficiency of these vessels was not permanently impaired : the most se- 

 rious injury, perhaps, occurred to the Passaic (monitor), which was 

 disabled by being struck at the base of its turret by a heavy shot, which 

 so jammed the contiguous plating as to prevent the tower from rotating. 

 The Keokuk, however, was more unfortunate. This vessel was smaller 

 than any of the monitors engaged, being plated with one and three- 

 fourths-inch plates on a four-inch backing of iron and wood ; the plates 

 being inclined at an angle which, amidships, was equal to 36, with a 

 view of deflecting shot striking against them. The unfitness of such 

 armor for defensive purposes was illustrated in a very few minutes af- 

 ter the Keokuk came under fire. The armor was riddled with shot in 

 every direction ; a considerable number of her crew were wounded, and 

 one killed, while the vessel herself sunk some twelve hours after the 

 conclusion of the fight. 1 



The Ironsides, a non-turreted broadside steamer, plated with four 

 and one-half inch solid armor, backed by from twenty-four to thirty inches 

 of oak, which took part in the above noticed attack, and in several 

 other subsequent actions, appears to be the most effective and in- 

 vulnerable of all the iron-plated vessels as yet constructed and sent in- 

 to service by the United States ; some even claiming that she is equiv- 

 alent to any six vessels of the monitor pattern. In "the various actions 

 in Charleston Harbor in which the Ironsides participated, from April 

 to September, she is reported to have been struck by shot and shell, 

 two hundred and thirteen times, none of which have caused serious in- 

 jury to life or limb of her crew, or essentially injured the vessel. The 

 water-line of the Ironsides alone bears the imprint of ten ten-inch 

 solid shot, while the most serious damage resulted from two shots strik- 

 ing the same plate, within a foot of each other, and within a foot of 

 the end of the plate. The result was the partial cracking of the 

 plate, bending it, and forcing it about an inch into the wood-work. It 

 occasioned no leak in the vessel. Several ten-inch solid shot, and one 

 eleven-inch, have passed through the unprotected part of the bow and 

 stern ; but so much of their momentum was lost in the passage, that 

 they did not reach the wrought-iron bulkheads that cross the ship for- 

 ward and aft, and which would have effectually stopped their further 

 progress. 



The method of fastening the plating to the sides of the Ironsides has 

 proved very effective. It consists of common wood-screws, put through 

 the plates from the outside, and tapped into the wood, having cylin- 



'All vessels with inclined armor are supposed to be so constructed that the shot 

 will glance from them without doing any damage. If we conclude, for the purpose 

 of argument, that the enemy will fire a round shot at a very low velocity, on a line 

 with the horizon, then the assumption may be correct. The fact of the matter is, 

 however, that inclined sides simply present to barbette guns the fairest target they 

 could desire, and the supposed efficiency of the angle is utterly neutralized. The 

 Galena, at Drury's Bluff, and other gunboats on the western rivers, which were 

 constructed with inclined armor, have been repeatedly pierced by guns fired from 

 elevations. Inclining the armor simply increases the thickness of the plating to 

 be pierced when the shot is fired on a line with the horizon. A plunging fire is re- 

 ceived by inclined plating fair and square, and there are no instances on record 

 where acutely-inclined armor has resisted the impact of the heaviest rifled shot at a 

 fair range. The Parrott 300-pounder'is said to have pierced nine inches of iron 

 inclined at an angle of 45, and the Stafford projectile is known to have penetrated 

 seven one-inch plates, heavily backed up with timber, at the same inclination. In- 

 clined sides, with inadequate armor, are simply a delusion and a snare. Scientific 

 American. 



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