Pennsylvania class steamship

USS Supply (formerly the Pennsylvania-class steamship Illinois)
Class overview
Name:	Pennsylvania
Builders:	William Cramp & Sons
Operators:	American Line
Cost:	$520,000 per ship ($2,080,000 total)
Built:	1872–1874
In service:	1873–1921
Completed:	4
Lost:	3
Retired:	1
General characteristics
Type:	Cargo-passenger liners
Tonnage:	3,104 gross
Length:	343–355 ft
Beam:	43 ft
Installed power:	Steam, auxiliary sails
Propulsion:	1,400 horsepower compound engine, single propeller
Speed:	11.5 knots
Complement:	83

The Pennsylvania class steamships—Pennsylvania, Ohio, Indiana and Illinois—were a class of four cargo-passenger liners built by the Philadelphian shipbuilder William Cramp & Sons in 1872–73. Intended for the newly established American Line, the four ships were at the time the largest iron ships yet built in the United States, and were launched with considerable fanfare. Upon entering service in 1874, they also became the first American-built steamships to challenge British dominance of the trade since the American Civil War.

Although soon outclassed by newer and larger vessels, all four of the Pennsylvania class steamships were to enjoy long and distinguished careers, the last of them being retired from service in 1921.

Since 1850, the Pennsylvania Railroad Company (PRR) had enjoyed a lucrative partnership with the British Inman Line, which transported European immigrants from Liverpool direct to Philadelphia, thus ensuring the Railroad a steady stream of customers. In 1857, the Inman Line switched its destination to New York, depriving the Pennsylvania Railroad of this lucrative trade. The Railroad made its first attempt to compensate for the lost traffic by organizing its own steamship line in 1863, but the plan was dropped after the Philadelphia city council declined to provide financial support.

After a failed attempt to gain control of a Scottish shipping line, the Anchor Line, in 1870, Pennsylvania Railroad decided to try establishing its own shipping line once again. It petitioned the Pennsylvania State Legislature for a charter for a new company to be known as the American Steamship Company (ASC), created to manage a new shipping line known as the American Line, which would be American's first transatlantic line since the end of the American Civil War. The Legislature granted the ASC its company charter in April 1871.