Lusitania and her sister-ship Mauretania were originally fitted with three-bladed propellers. In 1908 Mauretania had a new set of four-bladed propellers fitted, which immediately improved her speed.

RMS Lusitania was a Cunard transatlantic liner built on the Clyde ... her allies were war zones and as such any vessel flying the flag of Great Britain or her allies were liable for destruction.