OVERVIEW: The SHEFFIELD class (Type 42 Batch 1) is a COGOG-powered guided missile destroyer (DDG).

DETAILS:    The SHEFFIELD class was designed to provide area air defense for a task force. The class used a combined gas or gas  
(COGOG) to power its two shafts. In this system, a high efficiency, low output turbine is used for cruising speeds with a high output turbine being used for high-speed operations. The main problem with this engineering plant is the extreme noise it develops, rendering the Type 42 unsuited for long, slow stalking of a quiet submarine.  

Specifications: 

       Displacement:  3,500 tons (standard);  4,100 (full load)
       Speed: 29 knts
       Engineering: 2 shaft, 4 gas turbines (2 for full power, 2 for cruise)
       Range: 4,000 nm @ 18 knts
       Complement: 253 
       In Commission: 1975-2005 
       Completed: 6

NOTES: Units in class: SHEFFIELD (D80); BIRMINGHAM (D86); NEWCASTLE (D87); GLASGOW (D88); CARDIFF (D108); COVENTRY (D118).  Two units were also operated by the Argentine Navy. The Type 42 was conceived as a lighter and cheaper alternative to the Type 82, while maintaining much of the Type 82's capabilities.  The Type 42 achieved this by using a much smaller hull than the Type 82, deleting the Ikara ASW missile and the Limbo ASW mortar, and maxizing system centralization and automation, while minimizing system duplication, and using economical living spaces.  This made it possible to fit these capabilities into a small hull.
  

SOURCES: Moore, John Evelyn. Jane's Fighting Ships 1987-88.  London: Jane's Pub, 1987, pg. 662 ;  "Type 42 Destroyer." Wikipedia, the Free Encyclopedia. Accessed May 17, 2015. http://en.wikipedia.org/wiki/Type_42_destroyer ; "Type 42." GlobalSecurity.org - Reliable Security Information. Accessed May 17, 2015. http://www.globalsecurity.org/military/world/europe/type42.htm.