From Graces Guide
RMS (SS) Mauretania (also known as the "Maury") was an ocean liner designed by Leonard Peskett and built by Swan, Hunter and Wigham Richardson at Wallsend, Tyne and Wear for the Cunard Line, and launched on 20 September 1906.
At the time, she was the largest and fastest ship in the world. Mauretania became a favourite among her passengers. After capturing the Blue Riband for the fastest transatlantic crossing during her 1907 inaugural season, Mauretania held the speed record for twenty-two years.
The Mauretania and her sister RMS Lusitania were both designed by Cunard naval architect Leonard Peskett with Swan Hunter and John Brown working from the plans for an ocean greyhound with a stipulated service speed of twenty-four knots in moderate weather for her mail subsidy contract.
Peskett's original configuration for the ships in 1903 was a three-funnel design when reciprocating engines were destined to be the powerplant. A giant model of the ships in this configuration appeared in Shipbuilder's magazine.
Cunard in 1904 decided to change power-plants to Parsons' new turbine technology and Peskett then implemented a fourth funnel to the ship's profile as the ships design was again modified before construction of the vessel finally began.
1922 A New Atlantic Record
1922 Mauretania converter to burning oil. 
"On the return portion of her second trip since being converted for oile fuel firing the Mauretania easily surpassed the average speed which she maintained on her first trip. She arrived at Southampton on Monday morning five days, eight hours and fifty-six minutes after leaving New York. Her average speed was 25.14 knots. For a short time on the day before her arrival in port her speed touched 27.5 knots. She thus has not only accomplished the fastest Transatlantic crossing since the war, but broke her own and therefore the world's liner speed record." From The Engineer 1922/05/05.
1924 Read "Reconditioning the Turbines of The SS Mauretania" - The Engineer 1924/04/18.
"...In the spring of 1921 this vessel was converted from coal burning to oil fuel burning, the Cunard Co being fully alive to the many advantages of oil as a fuel in a ship of this type. Although since that time she has been running with remarkable regularity at a good average speed, she has not since the conversion equalled the previous best voyage run with coal..." Read more
1926 "When she was hurrying to the rescue of the British steamer Lakeham, the Mauretania attained a speed of 29 knots. The Mauretania was built some twenty years ago, for a speed of 25 knots."
1927 'The Cunard Liner Mauretania, which was recently overhauled and reconditioned at Liverpool, arrived at Southampton on Sunday afternoon (February 7th). Early the same morning a speed trial was carried out in the English Channel, and for two hours a speed of 26 knots was easily maintained.'
Sources of Information
- The Engineer 1922/03/17
- The Engineer 1926/04/16
- The Engineer 1926/02/11
-  Wikipedia