Baltimore-class cruiser
The Baltimore-class heavy cruisers were a class of heavy cruisers in the United States Navy commissioned during and shortly after World War II. Fourteen Baltimores were completed, more than any other class of heavy cruiser, along with another three ships of the sub-class. The Baltimores also were the first cruisers in the US Navy to be designed without the limitations of the London Naval Treaty.
Fast and heavily armed, the Baltimore cruisers were mainly used in World War II as anti-aircraft cruisers to protect the fast aircraft carriers in battle groups from air attack. Additionally, their main guns and secondary guns were regularly used to bombard land targets in support of amphibious landings. After the war, only six Baltimores and two Oregon City-class ships remained in service, while the rest were moved to the reserve fleet. However, all ships except Boston, Canberra, Chicago, and Fall River were reactivated for the Korean War.
Except for St. Paul, all the ships retaining all-gun configurations had very short service lives, and by 1971 were decommissioned, and started being sold for scrap. However, four Baltimore-class cruisers were refitted and converted into some of the first guided missile cruisers in the world, becoming two of the three and two cruisers. The last of these was decommissioned in 1980, with the Chicago lasting until 1991 in reserve. No example of the Baltimore class still exists.
History
Planning and construction
Immediately after the outbreak of World War II in September 1939, the US Navy initiated studies regarding a new class of heavy cruiser that led to construction of the Baltimore class. With the start of the war, the limitations instituted by the Second London Naval Treaty, which had completely banned the construction of heavy cruisers, became obsolete. The Baltimore class was based partly on, a heavy cruiser from 1937, which represented the transition from inter-war to World War II designs. It was also based partly on the, a light cruiser that was then being built. In profile, the Baltimores looked very much like the Cleveland-class light cruisers, the obvious difference being that the larger Baltimores carried nine guns in three triple turrets, compared to the twelve guns in four triple turrets of the Clevelands.The construction of the first four ships of the Baltimore class began on 1 July 1940, and four more were ordered before the year was out. A second order, which consisted of 16 more ships, was approved on 7 August 1942. Despite the heavy losses in cruisers during the first 14 months of the Pacific War, the completion of the ships was delayed because the Navy gave priority to the construction of the lighter Cleveland-class ships, as more of the lighter ships could be completed more quickly for deployment in carrier groups. With the construction of the first eight Baltimore-class ships moving slowly, the US Navy used the time to review the initial plans and improve them. The new, modified design was itself delayed, so that construction had begun on a further six ships—for a total of 14—using the original design before the revisions were completed. The final three ships ordered were converted to the second design, known as the Oregon City class. Between 1943 and 1947, 17 ships of the Baltimore and Oregon City classes entered service. Construction of the eighteenth ship was suspended, to eventually be completed as a flagship/command ship in 1950. Five more were laid down but cancelled and scrapped before launch, and one was never started before being cancelled.
The largest contractor for the construction of the Baltimore-class ships was Bethlehem Steel, which produced eight ships at the Fore River Shipyard in Quincy, Massachusetts. New York Shipbuilding in Camden, New Jersey, built four and the Philadelphia Naval Shipyard in Philadelphia completed two. The ships were named after cities in the United States, the only exception being, which was named in honor of , which had been named after Canberra, the Australian capital. The classification "CA" originally stood for "armored cruiser" but was later used for heavy cruisers.
Service
Of the seventeen completed ships, twelve were commissioned before the Japanese capitulation on 2 September 1945, though only seven took part in the battles of the Pacific Theater and one in the European Theater. By 1947, nine of the Baltimores had been decommissioned and placed in the reserve fleet, while seven remained in service. However, at the start of the 1950s, six were reactivated, making thirteen available for deployment in the Korean War. Six of these were used for escort missions and coastal bombardment in Korea, while the other seven reinforced fleets in other areas of the globe. Four ships remained out of service: the Fall River was never reactivated, the Boston and Canberra were refitted as Boston-class guided missile cruisers, and the Chicago was reactivated after being converted to an Albany-class CG.After the Korean War ended and due to the high cost of keeping them in service; starting in 1954 with Quincy, some of the Baltimores were decommissioned for good. By 1969, only six ships were still in commission; five as CGs, and only one unmodified ship, the Saint Paul, which remained active to serve in the Vietnam War, providing gunfire support. Saint Paul was the only member of the class to serve continuously from commissioning and was finally decommissioned in 1971. Boston and Canberra retired in 1970, Columbus in 1975, and finally Chicago in 1980. Starting in 1972 all fourteen of the original Baltimores were sold for scrap after being decommissioned, with Chicago being the final one broken up in 1991.
Damage
In World War II, only the was damaged through enemy fire, when she was struck with an air-dropped torpedo on 13 October 1944, which killed 23 men in the engine room and left the ship immobilized. The ship was hit amidships and both boiler rooms were flooded with 3,000 tons of seawater. She was towed away by sister ship, and as a result, both ships missed the crucial Battle of Leyte Gulf. A year later, repairs were completed at the Boston Naval Shipyard, and Canberra was assigned to the Atlantic Fleet. In June 1945, had her entire bow ripped off in a typhoon, but there were no casualties. The ship struggled through winds to Guam, where provisional repairs were made before sailing to the Puget Sound Naval Shipyard for a full reconstruction. Pittsburghs detached bow stayed afloat, and it was later towed into Guam and scrapped.During the Korean War, a fire in a forward gun turret on 12 April 1952, killed 30 men on St. Paul. Then, in 1953, the same ship was hit by a coastal battery, though without injury to the crew. Helena in 1951 and Los Angeles in 1953 were also struck by coastal batteries without injuries during the war.
In June 1968, Boston, along with its escort, the Australian destroyer, were victims of friendly fire when planes of the US Air Force mistook them for enemy targets and fired on them with AIM-7 Sparrow missiles. Only Hobart was seriously damaged; although Boston was hit, the warhead of the missile failed to detonate.
Missile conversions
By the latter half of the 1940s, the US Navy was planning and experimenting with warships equipped with guided missiles. In 1946 the battleship and in 1948 the seaplane tender were converted to test this idea. Both were equipped with, among other weapons, RIM-2 Terrier missiles, which were also used after 1952 on the first series of operational missile cruisers. Two Baltimore-class cruisers were refitted in this first series, and. These were the first operational guided missile cruisers in the world. They were designated the Boston class and returned to service in 1955 and 1956 respectively, reclassified as CAG-1 and CAG-2—"G" for "guided missile" and maintaining the "A" because they retained their heavy guns.In the following years, six light cruisers of the Cleveland class were retrofitted to be equipped with guided missiles, and in 1957, the first warship designed from the start to be a missile cruiser was completed. Other ships also continued to be converted, so starting in 1958, two Baltimore-class cruisers, and, along with an, , were converted to the new Albany class. These were recommissioned in 1962 and 1964, respectively. Two more ships were planned to be refitted as Albanys, the Baltimore class and the Oregon City class , but these conversions were cancelled because of cost. As opposed to the Boston-class refit, the Albany-class refit required a total reconstruction. Both entire weapons systems and the superstructure were removed and replaced with new ones; the cost of one refit was $175 million. Because no high-caliber guns were retained, the Albany class ships received the designation CG rather than CAG.
In addition to the operational conversions, four Baltimore-class ships,,,, and, received modifications to operate the SSM-N-8 Regulus cruise missile between 1956 and 1958 on an experimental basis. Regulus was a nuclear-armed weapon that was primarily used by the US Navy in the nuclear deterrent role. Although associated primarily with submarines, the four Baltimore-class cruisers fitted to operate the missile undertook operational taskings with it to the Western Pacific during the experimental period.
Engineering and equipment
Hull
Baltimore-class cruisers were long and wide. Since the hull was not altered in either the Albany or the Boston class, these numbers were the same for those ships as well, but the alterations differentiated them in all other categories.Fully loaded, original Baltimores displaced of water. Their draft was. At the bow, the top level of the hull lay above the water; at the stern,. The funnels were high, and the highest point on the masts was at. The superstructure occupied about a third of the ship's length and was divided into two deckhouses. The gap between these housed the two thin funnels. Two masts, one a bit forward and the other a bit aft of the funnels, accommodated the positioning electronics.
The vertical belt armor was thick and the horizontal deck armor was up to thick. The turrets were also heavily armored, between thick, while the conning tower had up to.
The Boston class had a draft about deeper in the water and displaced about more water than their former sister ships. Because the Bostons were only partially refitted, the forward third of the ship remained virtually untouched. The first serious change was the combination of what were two funnels on the Baltimores to just one, thicker funnel, which still stood in the gap between the two deckhouses. Because the missiles required more guiding electronic systems, the forward mast was replaced with a four-legged lattice mast with an enlarged platform. The most conspicuous change was of course the addition of the missile-launching apparatus and its magazine of missiles, which took up the entire back half of the ship and replaced the guns which had been there.
The three Albanys were completely rebuilt from the deck level up; except for the hull, they bore very little resemblance to their former sister ships. The deckhouse now took up nearly two-thirds of the ship's length and was two decks high for almost the entire length. Above that lay the box-shaped bridge which was one of the most recognizable markers of the class. The two masts and funnels were combined into the so-called "macks", combining "mast" and "stack", where the electronics platforms were attached to the tops of the funnels rather than attached to masts rising all the way from the deck. The highest points on the forward mack were more than above the water line. Such heights could only be achieved with the use of aluminum alloys, which were used to a great extent in the construction of the superstructures. Despite this, the fully loaded displacement of the Albanys grew to more than.