The classification of vessels in the navy includes four grades, commanded as follows: First rate vessels by commodores, second rate by captains, third rate by commanders, and fourth rate by lieutenant-commanders. Steamships, carrying forty or more guns, are classed as first rates, those of twenty guns and under forty as second rates, and all those of less than twenty guns as third rates.

How Vessels Are Named

The vessels of the navy are named by the Secretary of the Navy, under the direction of the President, according to the following rule: Sailing vessels of the first class, after the States of the Union, those of the second class after the rivers and principal cities and towns of the United States, and those of the third class as the President may direct. Steamships of the several classes are named in the same manner precisely, care being taken that not more than one vessel in the navy shall have the same name.

The Secretary of the Navy may change the names of any vessels purchased for the naval service.