ich could be very rapidly built and
put in commission. This last point was of cardinal importance, for report
said that work on the "Merrimac" was far advanced, and no ship could be
built on ordinary lines, of sufficient power to meet her, in the time now
available. The vessel must be of light draught to work in the shallow coast
waters, creeks, and river mouths of the Southern States. She might have to
fight in narrow channels, where there would not be room for manoeuvring to
bring broadside guns to bear. Ericsson, therefore, proposed that her
armament should be a pair of heavy guns mounted in a turret, which could be
revolved so as to point them in any direction, independently of the
position of the ship herself.

The hull was to be formed of two portions, a kind of barge-like structure
or lower hull, built of iron, and mostly under water when the ship was
afloat, and fixed over this the upper hull, a raft-like structure, wider
and longer, and with overhanging armoured sides and lighter deck-armour.
The dimensions were--

Upper part of hull, length 172 feet, beam 41 feet.
Lower hull, length 122 feet, beam 34 feet.
Depth, underside of deck to keel-plate, 11 feet 2 inches.
Draught of water, 10 feet.

Engines and boilers were aft, and the long overhang of the armoured deck
astern protected the under-water rudder and screw propeller. In the
overhang at the bow there was a well, in which the anchor hung under water.
Forward, near the bow, there was a small armoured pilot-house, or, as we
now call it, "conning-tower." Amidships, in an armoured turret, were
mounted two heavy smooth-bore guns, of large calibre, and throwing a round,
solid shot.

The conning-tower was built of solid iron blocks, nine inches thick. The
sight-holes were narrow, elongated slits. This was the helmsman's station.

The committee to which Ericsson's plans were referred was at first hostile;
some of the members declared that the ship would not float, that her deck
would be under water, and she would be swamped at once. Further objections
were that no crew could live in the under-water part of the hull. But at
length all objections were met, and the Swedish engineer was told that his
plans were accepted, and that a regular contract would be drawn up for his
signature. Ericsson knew the value of time, and before the contract was
ready the keel plates of his turret-ship had been rolled and a dozen firms
had started work on her various parts. While t