The Gorgon class originated from a specification for cruisers to be better than those of the German light cruisers placed on overseas postings, in the Far East and Pacific. To work in all of the big oceans and to be able to catch and overwhelm the German cruisers completing during 1914, required a ship of about 6,500 tons, approx, 500 feet, and armed with 7-8 6 guns. The latest Commonwealth cruisers, the Birmingham class ships, were smaller than these specifications and still had mainly broadside guns which affected the overall broadside. Putting all of the 6 guns on the centreline almost doubled the broadside compared to the older cruisers. The only way the Algarvian designers could achieve this was to put six of the 6 in three twin turrets on the centreline (one forward, and two aft), complimented with one single mounting forward, in a superfiring position. This was done as to mount a second twin turret forward would have required an even longer and larger cruiser.
Speed and range were comparable to the cruisers that were completing in 1916 at the same time as the Gorgons. The two very tall funnels certainly dated the ships design as forced draught was still a very useful tool for achieving speed.
Eventually six ships were laid down in pairs, 1914, 1915, 1917, with the last pair being completed in 1919. The first two ships of the class, Gorgon and Medusa, were taken in hand in 1939 to be converted to AA cruisers, these rebuilds completing in 1941. The other four were also to be converted, two in 1940-42, and the last two 1941-43. These were cancelled in 1939 on the outbreak of war and the four ships fought WW2 in their original layouts with additions that could be fitted. 1942-43 to assist with stability the aircraft handling facilities, torpedoes and other ancillary equipment (large ship boats etc) were removed while radar and other electronics were added.
As completed 1917:
Displacement: 6,250 tons normal, 7,950 tons full load.
Dimensions: 505 x 53 x 19 feet
Machinery: 2 shaft, steam turbines (oil fired), 60,000shp
Speed: 31 knots
Endurance: 8,000 miles at 15 knots.
Armour: 3 belt, 1 deck, 3/2/2 turrets
Armament:
7 x 6 (3x2, 1x1)
4 x 4 AA (4x1)
4 x mgs AA (4x1)
6 x 21 TT (2x3)
Crew: 550
As refitted to 1931:
Displacement: 6,250 tons normal, 7,950 tons full load.
Dimensions: 505 x 53 x 19 feet
Machinery: 2 shaft, steam turbines (oil fired), 60,000shp
Speed: 31 knots
Endurance: 8,000 miles at 15 knots.
Armour: 3 belt, 1 deck, 3/2/2 turrets
Armament:
7 x 6 (3x2, 1x1)
4 x 4 AA (4x1)
4 x mgs AA (4x1)
6 x 21 TT (2x3)
Aircraft: 1
Crew: 560
As rebuilt as AA cruisers 1939-41
Displacement: 6,450 tons normal, 8,250 tons full load.
Dimensions: 505 x 53 x 19 feet
Machinery: 2 shaft, steam turbines (oil fired), 60,000shp
Speed: 30 knots
Endurance: 8,000 miles at 15 knots.
Armour: 3 belt, 1 deck,
Armament:
8 x 4.5 (4x2)
24 x 40mm (12x2)
Crew: 560
As refitted to 1943:
Displacement: 6,300 tons normal, 8,050 tons full load.
Dimensions: 505 x 53 x 19 feet
Machinery: 2 shaft, steam turbines (oil fired), 60,000shp
Speed: 30 knots
Endurance: 8,000 miles at 15 knots.
Armour: 3 belt, 1 deck, 3/2/2 turrets
Armament:
6 x 6 (3x2)
6 x 4 AA (1x2, 4x1)
18 x 40mm (9x2)
Crew: 575
ARS Gorgon (1917)
ARS Medusa (1917)
ARS Sythena (1918)
ARS Euryalus (1918)
ARS Charybdis (1919)
ARS Cyclops (1919)