SS Demosthenes was a UK steam ocean liner and refrigerated cargo ship.

Harland and Wolff built Demosthenes on its slipway number five[1] in Belfast, launching her on 28 February 1911 and completing her on 5 August.

Her public areas included a verandah café, library, lounge, social hall and smoking room.

Pericles and Themistocles each had twin screws driven by quadruple-expansion steam engines whose combined power output was rated at 1,075 NHP.

A pair of four-cylinder triple-expansion steam engines drove her port and starboard screws.

The combined power output of her three engines was rated at 1,358 NHP,[9] which was 26 per cent more than her sisters, and gave her a speed of 15 knots (28 km/h).

[15] In August 1911 The Times more accurately described her as the first ship with a combination of reciprocating and turbine engines on the England – South Africa – Australia route.

She sailed from Royal Albert Dock, London and was scheduled to call at Plymouth, Tenerife and Cape Town on her way to Melbourne.

[10] She sailed in five convoys from Australia carrying elements of the First Australian Imperial Force for service overseas.

[16] On 17 August 1918 Demosthenes sailed from Quebec carrying troops including a party of 35 officers of the 69th Regiment, United States Army Coast Artillery Corps.

[18] On 20 July 1931 the Royal Mail Case opened at the Old Bailey, which led to the collapse of White Star Line's parent company.