[1] The R class were a development of the preceding M-class, but differed in having geared turbines, the central gun mounted on a bandstand and minor changes to improve seakeeping.

[1] Armament consisted of three 4 in (100 mm) Mk IV QF guns on the ship's centreline, with one on the forecastle, one aft on a raised platform and one between the second and third funnels.

[6] In October 1917, Rigorous formed part of a large-scale operation, involving 30 cruisers and 54 destroyers deployed in eight groups across the North Sea in an attempt to stop a suspected sortie by German naval forces.

[7] Despite these measures, the German light cruisers Bremse and Brummer managed to attack the regular convoy between Norway and Britain on 17 October, sinking nine merchant ships and two destroyers, Mary Rose and Strongbow before returning safely to Germany.

[8] The vessel was credited with bounty for sinking the German Q-ship K (also known as Kronprinz Willhelm) on 2 November 1917 along with Parker, Ready, Rocket, Rob Roy, Sorceress and Trenchant.