In 1905, based on submissions by the Committee of Imperial Defence, the Committee on Armaments of Defended Port Abroad recommended that the armaments for the following ports should be calculated to deter attack from the following class of warships. This includes most of the old Coaling Stations. (TNA CAB 16.1 1905 Report).  The Unarmoured Cruiser was sometimes called the Unprotected Cruiser.  The Protected Cruiser developed into the Battlecruisers which had battle ship armament but less armour and thus greater speed.  For more on Royal Navy Warships see here.