Topaze Class Third Class Cruisers

Topaze Class.  The last British third class cruisers they were larger, more heavily armed, better protected and faster than previous ships of this type and for the first time in British third class cruisers were expected to operate with the main fleet.  They also had improved sea keeping from the Pelorous class.

HMS Topaze
Built Laird, Birkenhead, laid down August 1902, completed November 1904.

HMS Amethyst
Built Armstrong, Elswick, laid down January 1903, completed March 1905.

HMS Diamond
Built Laird, Birkenhead, laid down March 1903, completed Jan 1905.

HMS Sapphire
Built Palmer, Jarrow, laid down March 1904, completed February 1905.

Average cost £240,000.

Size:
Length 360 feet pp 373 feet 9 inches overall, beam 40 feet, draught 14 feet 6 inches, displacement 3,000 tons load.

Propulsion:
2 shaft TE engines, 9,800 ihp, 21.5kts
Amethyst 3 shaft Parsons turbines 12,000 shp = 22.5 knots.

Trials:
Diamond 9,868 ihp = 22.1 knots
Sapphire 10,200 ihp = 22.3 knots
Amethyst 13,000 ihp = 23.6 knots

Armour:
1in gun shields, 2-0.5in decks

Armament:
12 x 4in QF (12 x 1), 8 x 3 pounder QF (8 x 1), 2 x 18in TT

Comments:
Often known as the Gem class.  Crew 296.

World War 1 Service:
Topaze
1914 Attached to the 5th Battle Squadron Channel.
1915 Mediterranean.
1917 Red Sea.
1921 Sold for scrap.

Amethyst
1914 Harwich force.
28 August 1914 Battle of Heligoland Bight.
1914 1st Light Cruiser Squadron Grand Fleet.
1915 Dardanelles.
1916 South America
1920 sold for scrap.

Diamond
1914 Attached to the 5th Battle Squadron Channel.
1915 Attached to the 5th Battle Squadron Grand Fleet.
1918 Mediterranean.
1921 Sold for scrap.

Sapphire
1914 Attached to the 4th Battle Grand Fleet.
1915 Mediterranean.
1916 East Indies.
1920 Sold for scrap.

HMS Amethyst was fitted with turbines, the first warship larger than a destroyer to be.  Turbines were more economical at higher power but less so at lower power so the ship was fitted cruising turbines.  Even so her range was 1500 nautical miles less than her sisters at 10 knots but 1000 nautical miles more at 20 knots.