Entering service starting in 1848, these six vessels permitted Cunard to double its schedule to weekly departures from Liverpool, with alternating sailings to New York.

[1] Larger and more powerful than the Britannias they replaced, the initial America quartette proved to be steady performers.

The initial units completed about 100 round trips and Europa lasted in the fleet for nineteen years.

The final two ships, Asia and Africa, completed 120 round trip voyages, the record for wooden steamships on the Atlantic route, and were not sold until 1868.

At that time, Cunard was receiving a mail subsidy from the Admiralty of £85,000 per year to operate five steamers on a fortnightly service from Liverpool to Halifax and then onto Boston.

[2] America and Niagara represented additions to the fleet while Europa and Canada replaced Britannia and Acadia, which were then sold to the North German Confederation Navy.

[1] America won the Blue Riband on her second outward voyage in 1848 with a run from Liverpool–Halifax of 9 days 16 minutes, averaging 11.7 knots (21.7 km/h; 13.5 mph).

On 14 February 1859 America made headlines when she broke through ice-choked Halifax Harbour after the normally ice-free port was paralyzed by a sudden freeze.

[5] Europa was the fastest of the initial quartette and won the Blue Riband with a voyage in October 1848 between Liverpool and Halifax of 8 days 23 hours, averaging 11.79 knots (21.84 km/h; 13.57 mph).

[1] Europa was also chartered as a troopship during the Crimean War and continued in Cunard service until 1867, when she was sold and converted to a sailing ship.