CAPTAIN ERICSSON has made a contract with the Government to construct two large iron-plated ships, which he believes will be the fastest and best sea boats, the most completely invulnerable, and the most formidable for attack, either at long range, or in close quarters, as rams, of any ships in the world.
They will bear a general resemblance to the Monitor, with such modifications as have been suggested by experience. One of them is to be 320 feet in length, and the other 341, with 50 feet beam. The vertical sides are six feet in depth, and are to be protected with iron armor plating, 10½ inches in thickness, backed with four feet solid oak.
The turrets are to be absolutely invulnerable. The contract provides that they shall be two feet in thickness, but the contractor has leave to reduce the thickness, provided he can satisfy the Department that less will be sufficient. A target has been constructed of thickness less than two feet, and forwarded to Washington for trial, but Capt. Dahlgren, who has been sending his 11-inch balls through a target like the side of the Warrior, with 30 lbs. of powder—making a clean hole at every shot—says that there is no use of firing at this target of Ericsson's until the 15-inch guns are finished. The turrets will be made of sufficient thickness to withstand the force of the 425-pounders with the maximum charges of the big guns.
The vessels are to be furnished with more powerful engines than any now afloat. Each ship will have two engines of 100 inches diameter of cylinder, with four feet stroke, to make 70 revolutions per minute, with boiler surface of 35,000 feet, and 1180 feet of grate surface. The boilers are of the upright water tubular pattern—a modification of Martin's. The propellers are Ericsson's patent, 21½ feet in diameter, and 30 feet 95pitch. The contractors guarantee a speed of 16 knots per hour—nearly nineteen miles.
The armament will consist of 15-inch guns, and will probably equal in destructive power that of any French or English ship. It is, however, as rams that these vessels will be the most formidable. Where the plates of the sides meet at the bow they form an iron wedge, 21 inches thick at the base, and terminating in a sharp edge. This wedge is sustained by the plates behind it, 10½ inches in thickness, six feet in depth, and extending the whole length of the vessel, forming the most powerful butting instrument that it is possible to conceive of. Captain Ericsson says, "It will split an iceberg."—Scientific American.