Fort Caswell was an old United States fort, much enlarged and strengthened.

Fort Fisher was a new work, begun immediately after the beginning of the war, and labored at incessantly until captured.

Behind these every one of the thirty-four miles to Wilmington was covered with the fire of the best guns the English arsenals could produce, mounted on forts built at every advantageous spot.

Lines of piles running out into the water, forced incoming vessels to wind back and forth across the stream under the point-blank range of massive Armstrong rifles.

As if this were not sufficient, the channel was thickly studded with torpedoes that would explode at the touch of the keel of a passing vessel.