The Steam warship classification system used during the 19th century was a classification scheme for the comparison of steam warships, including steam frigates and steam sloops. The system originally classified steam warships according to the thrown weight of their broadsides, then rated them by tonnage, using separate standards for ironclad and non-ironclad ships, with allowances for sailing ships still in commission. [1] It was used in the United States and United Kingdom, officially and unofficially. [2] The United States Navy adopted the system by 1875. [3]
(Weights given are representative) [4]
| Type | Shot weight (lbs) | |
|---|---|---|
| First Rate | 2,606 | |
| Second Rate | 1,220 | |
| Third Rate | 434 | |
| Fourth Rate | 210 / 294 |
| Type | Tonnage (non-ironclad) | Tonnage (ironclad) | |
|---|---|---|---|
| First Rate (also sailing ships-of-the-line) | 4000 + [5] | 8000 + | |
| Second Rate (also sailing frigates) | 2000 - 4000 | 2000 - 8000 | |
| Third Rate (also sailing sloops of war) | 900 - 2000 | 1200 - 2000 | |
| Fourth Rate (also dispatch vessels and store ships) | 0 - 800 | 0 - 800 |
. The History of the Navy During the Rebellion, Volume 1. Charles Brandon Boynton. D. Appleton and Company. 1870.
. The Statesman's Year-Book Statistical and Historical Annual of the States Of The Civilised World for the Year 1880. Frederick Martin (editor). MacMillan and Co.. 1880.
. Annual Report of the Chief of the Bureau of Steam-Engineering 1875. United States Navy Department. United States Government Printing Office. 1876.