The "Lusitania" was a Turbine steamship built by John Brown & Co., of Clydebank, in 1907, for the Cunard Steamship Company. She was built under Admiralty Survey and in accordance with Admiralty requirements, and was classes 100 A.1 at Lloyd's. Her length was 755 feet, her beam 88 feet, and her depth 60 feet 4 in. Her tonnage was 30,395 gross and 12,611 net. Her engines were of 68,000 h.p. and her speed 24 ½ to 25 knots. She had 23 double-ended and two single-ended boilers situated in four boiler-rooms.

The ship was divided transversely by eleven principal bulkheads into twelve sections.

The two forward bulkheads were collision bulkheads without doors. The remaining bulkheads had watertight doors cut in them which were closed by hand. On places where it was necessary to have the doors open for working the ship they could be closed by hydraulic pressure from the bridge. A longitudinal bulkhead separated the side coal bunkers from the boiler-room and engine rooms on each side of the ship.

The "Lusitania" was a passenger as well as emigrant ship as defined by the Merchant Shipping Acts. She fulfilled all the requirements of the law in this connection and had obtained all necessary certificates.

She had accommodation on board for 3,000 persons (including the crew).