USS Bon Homme Richard (CVA-31) underway during sea trials on 15 September 1955

SCB-125 was the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

designation for a series of upgrades to the of

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

s planned by the

Ship Characteristics Board The Ship Characteristics Board was a unit of the United States Navy. The purpose of the Ship Characteristics Board was to coordinate the creation of 'ship characteristics' that are essential to the design of naval combatants and auxiliaries. Coor ...

and conducted between 1954 and 1959. These upgrades included the addition of an

angled flight deck The flight deck of an aircraft carrier is the surface from which its aircraft take off and land, essentially a miniature airfield at sea. On smaller naval ships which do not have aviation as a primary mission, the landing area for helicopters ...

and other enhancements (such as with catapults and elevators) aimed at improving flight operations and

seakeeping Seakeeping ability or seaworthiness is a measure of how well-suited a watercraft is to conditions when underway. A ship or boat which has good seakeeping ability is said to be very seaworthy and is able to operate effectively even in high sea stat ...

Principal alterations

The SCB-125 modifications included * Angled flight deck * Enclosed hurricane bow * Mirror landing system * Mark 7 arresting gear * Primary Flight Control moved to aft end of island * Air conditioning * No 1 (forward) elevator lengthened (SCB-27C ships only) * No 3 (aft) elevator moved from centerline to starboard deck edge (on SCB-27A ships; had been part of SCB-27C refits)

Program history

The SCB-125 upgrade program was first applied to the final three ''Essex''-class carriers to undergo the SCB-27C modernization while they were still in the midst of their original refit. Ultimately every SCB-27 ship would undergo the SCB-125 modification with the exception of . Despite the drastic alteration of the carriers' appearance, the SCB-125 refit involved relatively little modification of the ships' existing structure compared to SCB-27, and took around six to nine months as against the approximately two years of the earlier program. The original SCB-27A vessels, which were fitted with a pair of H 8 hydraulic catapults, were not upgraded with the C 11 steam catapults fitted to their SCB-27C sister ships due to machinery space limitations. The SBC-27As also did not receive the enlarged No. 1 (forward) elevator installed in the 27C ships as part of SBC-125. The first three 27C ships (''Hancock, Intrepid'' and ''Ticonderoga'') had had their No 3 elevators moved from the centerline to the starboard deck edge, in a position relatively far aft. The next three (''Shangri-La, Lexington'' and ''Bon Homme Richard''), which underwent 27C and 125 concurrently, had the elevator relocated to a deck-edge position farther forward, and this location was used for the 27A ships as they in turn underwent SCB-125. , the prototype for the SCB-27 conversion, was the final ''Essex'' to undergo SCB-125 conversion and as such, received further enhancements. As a result of the addition of aluminum flight-deck cladding, Mk 7-1

arresting gear An arresting gear, or arrestor gear, is a mechanical system used to rapidly decelerate an aircraft as it lands. Arresting gear on aircraft carriers is an essential component of naval aviation, and it is most commonly used on CATOBAR and STOBA ...

and more-powerful C 11-1

steam catapults An aircraft catapult is a device used to allow aircraft to take off from a very limited amount of space, such as the deck of a vessel, but can also be installed on land-based runways in rare cases. It is now most commonly used on aircraft carrier ...

to the standard SCB-125 modifications, ''Oriskany'' alone was referred to as a SCB-125A vessel. These changes also made ''Oriskany'' the only SCB-27A vessel to receive steam catapults.

Modified vessels

''Source: www.history.navy.mil'' ¹ ''Lexington'' was redesignated CVA upon completion of SCB-27C/125

References

Naval Historical Center page on SCB-125 program
{{Essex class aircraft carrier Essex-class aircraft carriers