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.

[73] bold, in view of the fact that half an hour after the last shot was fired the Minnesota was lying aground in the very spot she had occupied in the morning, the Monitor was lying alongside her, neither of them being materially injured, and the supposed victor was steaming as fast as possible to Elizabeth River, in order to cross the bar before the ebbtide.

Though both the ironclads were severely pounded in the engagement, neither had developed fully its offensive strength, and all things considered they got off rather easily. The only serious casualty on either side was the injury received by Worden. The Merrimac leaked somewhat from the collision of her unarmed stem with the Monitor's overhang, and the plates of her armor were broken where they were struck, but the wooden backing was not penetrated. The roof of the Monitor's pilot-house was partly displaced, and one of its beams was cracked; but otherwise the vessel was left intact. She was struck twenty-one times; eight times on the side-armor, twice on the pilot house, seven times on the turret, and four times on deck. The deepest indentations on the sides were four inches, on the turret two inches, and on the deck one inch. Had the Monitor's guns been depressed to strike the enemy at the water line, where there was only one inch of armor, or had the latter concentrated his fire on the pilot-house of the Monitor, which was her weakest point, the result might have been more decisive. So with the ordnance. The service charge for the Xi-inch guns was fifteen pounds, and the Bureau had enjoined upon Worden to limit himself to this, though it was found later that thirty pounds could be safely used; and on the other hand, owing to the great demand among the Confederates for projectiles at other points, and to the supposition that she would have only wooden vessels to encounter, the Merrimac was not supplied