The _Cumberland_ and _Congress_ men-of-war moved out in that direction, and the _Minnesota_ and the _St.Lawrence_, which were at anchor, got under way, assisted by steam tugs.
The _Merrimac_ and the fleet of little gunboats were now visible from the battery, advancing against the _Cumberland_ and _Congress_.

The former opened fire upon her at a distance of a mile with the heavy pivot guns, but the _Merrimac_, without replying, continued her slow and steady course toward them.

She first approached the _Congress_, and as she did so a puff of smoke burst, from the forward end of her pent-house, and the water round the _Congress_ was churned up by a hail of grape-shot.

As they passed each other both vessels fired a broadside.
The officers in the fort, provided with glasses, could see the effect of the _Merrimac's_ fire in the light patches that showed on the side of the _Congress_, but the _Merrimac_ appeared entirely uninjured.

She now approached the _Cumberland_, which poured several broadsides into her, but altogether without effect.
The _Merrimac_, without replying, steamed straight on and struck the _Cumberland_ with great force, knocking a large hole in her side, near the water line.