James Russell Soley, Professor U. S. Navy, Confederate Military History, a library of Confederate States Military History: Volume 7.1, The blockade and the cruisers
Clement Anselm Evans, Ed.

[15] 32 pounder, which was simply a development of the 18s and 24s of 1812, and the Viii-inch shell-gun were still the usual guns. Since 1850, the powerful Dahlgren smooth-bore shell-guns had been introduced, and the new steam-frigates and sloops were armed with them. The Ix-inch guns of this description were mounted in broadside, and the Xi-inch (with a few X-inch) on pivots. The powers of the Xi-inch had not been fully tested, and the prescribed service-charge was smaller than it was afterward found that the gun would bear. The latest development of the smooth-bore gun was the Xv-inch, one of which was generally mounted in each monitor turret. Rifled guns were gradually introduced during the war. These were chiefly Parrott guns, 20-, 30-, and 100-pounders. They were cast-iron guns, strengthened by a wrought-iron band around the breech. Later, 60-pounders and 150-pounders were manufactured. The Parrott gun of the smaller calibres was serviceable, but as a heavy gun it was dangerous, and occasionally burst. Besides the Parrott guns, a few light cast-iron Dahlgren rifles were made; and in the Western flotilla, when it was transferred to the navy, there were several army rifled 42-pounders, which were so dangerous as to be nearly useless.

The demands of the new service were many and various. There was the river service, where the navy acted largely in co-operation with the army, in the reduction of fortified points, and in opening and keeping open the lines of communication. For this the essential qualification was light draft. It needed small handy vessels, capable of approaching the shore, and of passing through shallow and difficult channels. Quite distinct from it was the ocean service, which meant the pursuit and capture of Confederate cruisers, and of vessels engaged in illegal trade. The prime necessity here was speed. Lastly, there was the coast service,