OVERVIEW: The Type 21 aka AMAZON-class frigate is a two-shaft, COGOG-powered, multi-role, guided missile frigate.

DETAILS: The Type 21 frigate was intended as an inexpensive general-purpose escort.  Unlike previous RN ship designs, the Type 21 was designed by a private shipbuilder under less rigorous Royal Navy supervision. This resulted in being at or near their maximum topweight limit, with no allowance for future expansion of the design. Despite the use of aluminum alloy in the superstructure to reduce top weight, the class remained top-heavy.  This lack of topweight margin meant that the class could not be upgraded and resulted in their being retired from Royal Navy service after less than 20 years of service.   The class was also less damage resistant.  A 1977 fire on the HMS AMAZON showed that the aluminum construction made the class more vulnerable to fire, and the and heavy weather and differential expansion of the aluminum and steels hulls the ships experienced during the Falkland war resulted in their hulls cracking, requiring them to be strengthened at the end of the conflict.  

Type 21 was multi-mission capable.  The anti-surface systems of the class included a 4.5 inch Mk 8 gun. Four MM.38 Exocet SSMs were subsequently added.   Anti-air capability was provided by a SEA CAT SAM system. Both the Seacat and the gun were controlled by the Type 912 fire control radar.   Antisubmarine capability was provided by an embarked helicopter and, after refit, six torpedo tubes for the Mk44/46 ASW torpedoes. ASW search capability was done by a Type 184M hull mounted sonar.

The electronics suite consisted of a medium-range Type 992Q air/surface radar and a Type 978 navigation radar

Aviation facilities include a hanger for a single embarked Wasp or Lynx helicopter.

SPECIFICATIONS:
Displacement: 3,250 tons (full)
Speed: 32 kts
Engineering: COGOG, 2 X Tyne cruise gas turbines @4,250 shp each, 2 X Olympus boost turbines @25,000 shp each,  2 shafts.
Range: 4,000 nm @ 17 knts; 1,200 nm @ 30 knots.
Endurance: 60 days
Complement: 177 crew

NOTES: IOC: 1974.  Their handsome looks combined with their impressive handling and acceleration prompted the class nickname "Porsches". Units in class: AMAZON (F169); ACTIVE (F 171); AMBUSCADE (F 172); ARROW (F 173); ALACRITY (F 174); AVENGER (F 185). ARDENT (F 184) and ANTELOPE (F 170) lost during Falkland Islands war. 


SOURCES:  Prezelin, Bernard (ed) Naval Institute Guide to Combat Fleets of the World, 1990-91,  Annapolis, MD: Naval Institute Press, 1990, pg. 712. ; "Amazon Class Type 21 Frigate - Royal Navy." Seaforces Online - Naval Information. Accessed November 16, 2022. https://www.seaforces.org/marint/Royal-Navy/Frigate/Amazon-Type-21-class.htm. ; McClearn, Sandy. "AMAZON Class Frigate." Haze Gray & Underway - Naval History and Photography. Accessed November 16, 2022. https://www.hazegray.org/navhist/rn/frigates/amazon/.
