SCB-27 modernization of Essex/Ticonderoga class aircraft carriers

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Between 1947 and 1955, fifteen Essex and Ticonderoga class aircraft carriers were thoroughly modernized. The impending arrival of high-performance jet aircraft and nuclear-armed heavy attack bombers had rendered these still rather new ships almost incapable of executing their most vital missions, while the post-World War II financial climate precluded building replacements. Accordingly, a reconstruction program began in Fiscal Year 1948, with the incomplete Oriskany as the prototype. Two more ships were converted the next year, three in FY 1950 and then, with the the Cold War in full bloom, nine more Fiscal Years 1951 to 1953.

Designated SCB-27, the modernization was very extensive, requiring some two years for each carrier. To handle much heavier, faster aircraft, flight deck structure was massively reinforced. Stronger elevators, much more powerful catapults, and new arresting gear was installed. The original four twin 5"/38 gun mounts were removed. The new five-inch gun battery consisted of eight weapons, two on each quarter beside the flight deck. Twin 3"/50 gun mounts replaced the 40mm guns, offering much greater effectiveness through the use of proximity-fuzed ammunition.

A distinctive new feature was a taller, shorter island. To better protect aircrews, ready rooms were moved to below the armored hangar deck, with a large escalator on the starboard side amidships to move airmen up to the flight deck. Internally, aviation gasoline storage was increased by nearly half and its pumping capacity enhanced. Also improved were electrical generating power, fire protection, and weapons stowage and handling facilities. All this added considerable weight: displacement increased by some twenty percent. Blisters were fitted to the hull sides to compensate, widening waterline beam by eight to ten feet. The ships also sat lower in the water, and maximum speed was slightly diminished.

The modernized ships came in two flavors, the first nine (SCB-27A) having a pair of H 8 hydraulic catapults, the most powerful available in the late '40s. The final six received the SCB-27C update, with much more potent steam catapults, one of two early 1950s British developments that greatly improved aircraft carrier potential. These six were somewhat heavier, and wider, than their sisters. While still in the shipyards, three of the SCB-27Cs were further modified under the SCB-125 project, receiving the second British concept, the angled flight deck, plus an enclosed "hurricane bow" and other improvements. These features were so valuable that they were soon back-fitted to all but one (Lake Champlain) of the other SCB-27 ships. The fourteen fully modernized units were the "journeymen" aviation ships of the late 1950s and 1960s, providing the Navy with much of its attack aircraft carrier (CVA) force and, ultimately, all its anti-submarine warfare support aircraft carriers (CVS).

The SCB-27 program involved rebuilding fifteen ships, three of which were given a combined SCB-27 and SCB-125 modernization. The reconstructed ships are listed below, in the order of completion:


Oriskany (CV-34). Built by the New York Naval Shipyard. Keel laid in May 1944; launched in October 1945; reordered to the SCB-27A design in August 1947; commissioned in September 1950.

Essex (CV-9). Reconstructed to SCB-27A design by the Puget Sound Naval Shipyard. Work began in February 1949; recommissioned in January 1951.

Wasp (CV-18). Reconstructed to SCB-27A design by the New York Naval Shipyard. Work began in May 1949; recommissioned in September 1951.

Kearsarge (CV-33). Reconstructed to SCB-27A design by the Puget Sound Naval Shipyard. Work began in February 1950; recommissioned in February 1952.

Lake Champlain (CV-39). Reconstructed to SCB-27A design by the Norfolk Naval Shipyard. Work began in August 1950; recommissioned in September 1952.

Bennington (CV-20). Reconstructed to SCB-27A design by the New York Naval Shipyard. Work began in December 1950; recommissioned as CVA-20 in November 1952.

Yorktown (CV-10). Reconstructed to SCB-27A design by the Puget Sound Naval Shipyard. Work began in March 1951; recommissioned as CVA-10 in February 1953.

Randolph (CV-15). Reconstructed to SCB-27A design by the Newport News Shipbuilding and Dry Dock Co. Work began in June 1951; recommissioned as CVA-15 in July 1953.

Hornet (CV-12). Reconstructed to SCB-27A design by the New York Naval Shipyard. Work began in July 1951; recommissioned as CVA-12 in September 1953.

Hancock (CV-19). Reconstructed to SCB-27C design by the Puget Sound Naval Shipyard. Work began in December 1951; recommissioned as CVA-19 in February 1954.

Intrepid (CV-11). Reconstructed to SCB-27C design by the Newport News Shipbuilding and Dry Dock Co. Work began in April 1952; recommissioned as CVA-11 in June 1954.

Ticonderoga (CV-14). Reconstructed to SCB-27C design by the New York Naval Shipyard. Work began in April 1952; recommissioned as CVA-14 in September 1954.

Shangri-La (CVA-38). Reconstructed to SCB-27C design by the Puget Sound Naval Shipyard. Work began in October 1952 and was extended to include SCB-125 features; recommissioned in January 1955.

Lexington (CVA-16). Reconstructed to SCB-27C design by the Puget Sound Naval Shipyard. Work began in September 1953 and was extended to include SCB-125 features; recommissioned in August 1955.

Bon Homme Richard (CVA-31). Reconstructed to SCB-27C design by the San Francisco Naval Shipyard. Work began in May 1953 and was extended to include SCB-125 features; recommissioned in September 1955.


Essex/Ticonderoga class characteristics, as modified under project SCB-27A:


Displacement: 40,600 tons (full load)

Dimensions: 898' (length overall); 101' 4" (hull); 151' 11" (over flight deck and projections)

Powerplant: 150,000 horsepower, steam turbines, four propellers, 31.7 knot maximum speed

Aircraft ("ultimate" planned 1958 complement): 72 planes, including 24 15,000 pound interceptors, 24 30,000 pound escort fighters and 24 30,000 pound attack bombers. The actual aircraft complement carried was quite different.

Gun Armament: eight 5"/38 guns in single mountings plus fourteen twin 3"/50 gun mounts. From the mid-1950s onward, gun armament was rapidly reduced.
  
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