Colorado - class battleship The " Colorado " class battleships was a group of four battleships built by the United States Navy after World War I . However , only three of the ships were completed : , , and . The fourth , , was over 75 % completed when she was canceled under the terms of the Washington Naval Treaty in 1922 . As such , the " Colorado " class ships were the last and most powerful battleships built by the US Navy until the entered service on the eve of World War II . The " Colorado " s were the final group of Standard - type battleship s , designed to have similar speed and handling to simplify maneuvers with the line of battle . ( The " South Dakota " class which was to follow would in several ways have been a departure from this practice . ) Apart from an upgrade in striking power to eight 16 - inch guns , the ships were essentially repeats of the earlier . The " Colorado " s were also the last American capital ships built with four turret s and twin - mounted guns . The change to larger guns was prompted by the Japanese s , which also mounted eight 16 - inch guns . All three ships had extensive careers during World War II . " Maryland " and " West Virginia " were both present during the attack on Pearl Harbor on 7 December 1941 . " Maryland " escaped relatively unscathed ; " West Virginia " was sunk in the shallow waters of the harbor but subsequently raised and repaired . All three ships served as artillery support ships during amphibious operations . " Maryland " and " West Virginia " were present at the last surface action between battleships , the Battle of Surigao Strait during the Battle of Leyte Gulf in October 1944 . The three ships , put into the reserve fleet after the end of the war , were scrapped by the late 1950s . Design . The construction of battleships armed with 16 - inch guns was envisioned by the United States Navy General Board and Bureau of Construction and Repair ( C & R ) as early as 1913 , as the upgrade in gun caliber promised twice the kinetic energy of the 12 - inch gun then in service and half again as much as the 14 - inch gun then being introduced . This weapon dominated the design of battleships between 1913 and 1916 , just as the 14 - inch gun had dictated designs from 1908 to 1910 . However , while the General Board approved the 16 - inch gun as early as 1911 , the secretary of the navy felt that a move to a new gun caliber might make capital ships still on the drawing board obsolete . For this reason , he restricted the Bureau of Ordnance to proceed no further than blueprints for the new gun as a hedge against foreign developments . He finally approved construction of this gun in October 1912 and the weapon was test fired successfully in August 1914 . This success , along with the unofficial news in several naval publications of 15 - and 16 - inch weapons being adopted by Britain , Italy , Germany and Japan , the Board considered abandoning construction of the in favor of an up - gunned design . Such a move meant an increase of 8 , 000 tons per ship , twice as much as the jump from the s to the " Pennsylvania " s . Debate continued for the next three years . Each year , President Woodrow Wilson ' s secretary of the navy , Josephus Daniels , balked at the potential increase in cost and ordered instead that the design features of Standard Class be upheld . Daniels finally compromised with the 1917 design battleships by allowing their armament to be upgraded . This , however , was to be the only substantial change to be allowed The design of the " Colorado " class , therefore , was taken from the preceding ; other than the notable improvement of eight / 45 caliber in four dual turrets taking the place of the " Tennessee " - class ' s twelve / 50 caliber gun s in four triple gun turrets , there was not a major difference between the two designs . Likewise , the " Tennessee " s were the results of modifications to the , which had been the most modern US capital ships to see service in World War I and had attracted the attention of British constructors both serving with and outside C & R . This similarity would carry over into the and " South Dakota " classes as the United States Navy increasingly standardized its capital ship designs . This was partly the result of wartime experience , when over 250 destroyers and more than 450 submarine chasers had to be built quickly for service in the North Atlantic . The U . S . Navy had done this by a process almost akin to the assembly line , sticking to one basic design per class with a maximum amount of standardization and rationalization . Since the Naval Act of 1916 meant the imminent construction of 16 battleships and six battlecruiser s , it was necessary to streamline production to save time and labor . Nevertheless , while US battleships were standardized as much as possible , design improvements were incorporated whenever possible . Most of the changes in the " Tennessee " s were incorporated prior to any of their keels being laid . However , plans for the underwater protection — the ships ' main defense against torpedo es and shells that fell short of the ship but traveled through the water to hit underneath the waterline — could not be worked out in time . The problem was that tests in caissons — experiments that would eventually prove that a series of compartments divided between being filled with liquid and being left empty would be a very effective defense against torpedoes — were not yet complete . In order to commence construction of the ships as soon as possible , bids sent out to shipbuilding corporations noted that if they were selected to build the ships , an alteration to the design of the ships three months after their keels were laid must be allowed . General characteristics . The " Colorado " s were extremely similar overall to the " Tennessee " s , with a overall length and a beam at the waterline of . They displaced at normal load and at deep load and had a draft of . Like the " Tennessee " s , they were designed with a clipper bow to make the ships dryer in rough weather . One improvement over previous classes was the location of the secondary battery in the superstructure rather than the upper hull , where it had proved to be excessively wet . Propulsion . Turbo - electric transmission , which had been used in most of the other Standard type capital ships , was retained here . Advantages included the ability for the turbines to run at optimum speed without regard to propeller speed , which led to greater fuel economy and range , and an easier sub - division of machinery , which increased the ships ' ability to withstand torpedo hits . Each of the four propeller shafts was powered by a 5424 kilowatt electric motor , fed by two two - phase turbo generator s ( General Electric for " Maryland " , Westinghouse for " Colorado " and " West Virginia " ) rated at 5000 volts ) . Eight oil - fired Babcock & Wilcox water - tube boilers , each in its individual compartment , provided steam for the generators . Altogether , the ships ' power plant was rated at 28 , 900 electrical horsepower ( EHP ) to provide a flank speed of . With a maximum bunker capacity of 4570 tons , the " Colorados " ' range without refueling at sea was 10 , 000 nautical miles . Armament . Main guns . The " Colorado " class was armed with eight 45 caliber Mark 1 guns , which fired a armor piercing ( AP ) shell at a muzzle velocity of and a rate of about 1 . 5 rounds per minute to a range of at a maximum turret elevation of 30 degrees . Development of this weapon had begun in August 1913 , using a bored - out and relined Mark 2 gun , with the promise of twice the muzzle velocity of the 50 caliber gun and 50 percent more than the 45 caliber weapon used on the " Nevada " class battleships . After an initial proof firing in July 1914 and minor changes , the 16 " Mark 1 was re - proved in May 1916 and production approved in January 1917 . When the " Colorado " s were modernized in the 1930s , these guns were rebuilt per standard navy practice and redesignated 16 " / 45 ( 40 . 6 cm ) Mark 5 and Mark 8 . Secondary guns . Fourteen 5 in ( 127 mm ) / 51 caliber Mark 15 guns were installed to defend against enemy destroyers . This was reduced to 12 in 1922 . The Mark 15 fired a shell at a velocity of to a maximum range of at 45 degrees at a rate of seven rounds per minute and was extremely accurate , with a danger space longer than the range to the target for distances less than . As in the " New Mexico " and " Tennessee " classes , these were mounted in unarmored casemates on the main deck , one deck higher than in previous classes , to allow them to be manned in heavy weather if necessary . In 1942 , the Mark 15 guns were replaced on " West Virginia " with sixteen 5 - inch 38 caliber Mark 12 dual - purpose guns in twin turrets . On " Maryland " and " Colorado " ten Mark 15s were retained and augmented with eight 5 " / 38 cal Mark 12s in single mountings with protective shields ; the twin turrets planned and later installed were at that time in short supply . The Mark 12 fired a shell to a maximum range of and a maximum elevation of at an elevation of 45 degrees . They had a high rate of fire due to their being hand - loaded but power - rammed and their capability for easy loading at any angle of elevation . The introduction of proximity - fused anti - aircraft shells in 1943 made the 5 " / 38 even more potent in this capacity . Anti - aircraft guns . Four 3 inch 23 caliber guns were mounted initially for anti - aircraft ( AA ) defense . This was increased to eight guns in 1922 . These guns fired a shell at a muzzle velocity of to a maximum range of and ceiling of at an elevation of 45 . 3 degrees and a rate of between eight and nine rounds per minute . These weapons were replaced in 1928 - 9 with the same number of 25 caliber guns , the first Navy gun designed specifically for AA use . They fired a shell at a muzzle velocity of at a rate of between 15 and 20 rounds per minute to a maximum range of at an elevation of 45 degrees and a ceiling of at a maximum elevation of 85 degrees . These guns were supplemented with eleven 28 mm machine gun s in 1937 - 8 . In 1942 , the air defense system on these ships was overhauled completely . In addition to her 5 " / 38s , they carried sixteen Bofors 40 mm guns in quad mounts and up to thirty - two Oerlikon 20 mm cannon s in single mounts . The quad 40mm Bofors fired a at a rate of 120 rounds per minute per barrel nominal , 140 to 160 rounds per minute when horizontal ( gravity assist ) , to a maximum range of at 45 degrees and a ceiling of . The 20mm Oerlikons fired a shell at an average muzzle velocity of and a practical rate of between 250 and 320 rounds per minute to a maximum range of at 45 degrees and a ceiling of . A second overhaul of AA defense was made between 1944 and 1945 , as the Navy had found 20 mm shells too light to stop Japanese Kamikaze planes ; this plus the higher approach speeds of these planes made these manually controlled guns obsolete . In their place , more quad 40mm Bofors mounts were fitted . " Maryland " eventually carried forty quad 40mms and eighteen 20mm . " Colorado ' s " quad 40s were increased to forty but she kept all her 20mms . " West Virginia " carried forty quad 40mms and fifty 20mms . Armor and underwater protection . The " all or nothing " armor scheme introduced in the " Nevada " class battleships was continued here , as throughout the Standard type warships , with armor suite virtually identical to the preceding " Tennessee " class . The exception was an increase in belt armor near vital machinery to to correspond with the increased main gun caliber . Otherwise , the minimum thickness along the belt remained . Upper deck armor was initially and was later increased to . Lower deck armor ranged between and was also presumably strengthened during conversion . As with the " Tennessee " s , the " Colorado " s ships were modernized in the 1930s to improve their staying power . A new underwater protection scheme featured five compartments separated by armored bulkheads thick on either side of the ship : an outer empty one , three filled , and an empty inner one . In addition , the eight boilers were moved from their location in previous designs and placed in separate spaces to port and starboard of the turbo - electric power plant . This arrangement formed another line of defense , which would allow the ship to sail if one or even an entire side of boilers was incapacitated . A consequence was the chief aesthetic change between the " New Mexico " s and " Tennessee " s : the single large funnel of the former was replaced by two smaller funnels in the latter . Other improvements imported from the " Tennessee " class included an attempt to move the forward torpedo room away from the 16 " gun magazines , as the room was viewed as vulnerable . Also , the design called for the use of external , rather than internal , belt armor so that a " break in the continuity of the side structure " would not exist , which would minimum drag in the water and any corresponding waste of power . Class history . With fiscal year 1917 appropriations , bids on the four " Colorado " s were opened on 18 October 1916 ; though " Maryland " s keel was laid on 24 April 1917 , the other three battleships were not until 1919 – 1920 . With the cancellation of the first " South Dakota " class , the " Colorado " s were the last U . S . battleships to enter service for nearly two decades . They were also the final U . S . battleships to use twin gun turrets — the s and second " South Dakota " classes had nine 16 " / 45 caliber guns and the s used nine 16 in / 50 caliber in three triple turrets . Inter - war Modernization . Plans for modernization of the " Tennessee " and " Colorado " classes were made in October 1931 , in part to take advantage of loopholes in the Washington Naval Treaty . While reconstruction under this treaty was allowed only to increase protection from air and underwater attack , it could include improvements in fire control and increased elevation for main armament as these items were not listed in the treaty . Also , any changes made inside the hull could be justified as meant to increase protection , even if the outcome meant increased speed or longer operational range , since the term " blister " had been specified to limit changes only outside the hull , such as main armor belt thickness and main gun caliber . Modifications to the secondary battery were also outside the purview of the Washington Treaty . Included in initial plans was some protection against chemical shells which contained poisonous gas , although the General Board stated in the late 1920s that decontaminating a battleship hit with these shells would not be possible — the ship would have to be scuttled . Also , the deck armor was to be bolstered with - special treatment steel ( STS ) — which would add to the displacement of the ships — the armor on the tops of the main turrets was to be made thicker , fire controls were to be improved with the latest technology , and new shells for the main guns were to be designed . Two , later four , 1 . 1 " / 75 caliber machine cannons were to be added , and all of the machinery in place would be removed in favor of newer equipment so that the ships would not lose any speed with the great increase in weight . Blisters were also to be installed to improve buoyancy but not to increase the ships ' beams any greater than so they could still use the Panama Canal when transferring from the Atlantic to the Pacific and vice verse . These improvements were estimated to cost about US $ 15 , 000 , 000 per ship ( $ 71 , 723 , 000 total ) . However , with the country in the throes of the Great Depression , not much money was available for the Navy . Savings of $ 26 , 625 , 000 could be realized by reconditioning the propulsion machinery rather than replacing it . which would lower the ships ' speed . Adding protection against chemical shells could be dropped , along with development of the new shells . Nevertheless , the cost - saving elements of the later proposal were later dropped . The Navy asked the Secretary of the Navy to request money in the fiscal year 1933 to modernize the two classes from Congress , but the depression worsened . Although proposals for modifications were still made , plans were put on hold and never carried out . In the beginning of 1934 , the Bureau of Construction and Repair proposed that the " Big Five " — the two " Tennessee " s and three " Colorado " s — be fitted with anti - torpedo bulge s so that the ships could benefit from increased buoyancy ; because of , among other factors , the normal procedure of leaving port with the maximum amount of fuel possible on board , the five ships were quite overweight and rode low in the water . For example , in June 1935 , " Tennessee " had a normal operating displacement of — more than above the maximum emergency load her original design called for . This made her draft higher — meaning that the ship ' s waterline was down . Construction and Repair called for a bulge on the " Colorado " s that would displace about and raise the ships ' draft by . Installing these would be a year ' s worth of work , with each ship spending six months of that in a dry dock — the first month docked so that the hull shape could be determined , the next six sailing while the bulge was built , and the last five back in the dock so it could be added to the ship . Three years later ( 1937 ) , the various Navy bureaus held a joint meeting to discuss a possible partial modernization of the " Tennessee " s and " Colorado " s . They were much different than the changes proposed in 1933 ; there were no provisions for extra deck armor , but many additions and replacements . To gain space for newer fire control systems , the ships were to be reboilered . The main and secondary battery fire controls were to be replaced , including new rangefinders and plotting room instruments for the main , while new Mark 33 anti - aircraft fire control directors were planned . The mainmast and M2 Browning machine gun s would be removed , and studies of the feasibility of a torpedo bulge , the addition of which Construction and Repair believed to be paramount , which would increase the beam to and displacement to . Varying plans for these were complete by October 1938 . None was a full reconstruction ; costs ranged from $ 8 , 094 , 000 to $ 38 , 369 , 000 per ship . However , as the money for the improvements would lessen the amount available for new battleship construction , and these would be better than even reconstructed old battleship , the Secretary of the Navy rejected these plans in November . Congress did appropriate $ 6 , 600 , 000 in 1939 for some of these improvements , including the bulges . World War II Changes . With the beginning of World War II in Europe , the Navy began to apply lessons learned by the British there to U . S . ships . The King Board of 1940 – 1941 proposed sweeping changes to the secondary armament of the battleships to increase their defense against air attacks . These included the removal of all / 25 caliber guns and 5 in / 51 in favor of the dual - purpose 5 in / 38 , the addition of six quadruple machine cannons , and the cutting away of superstructure to clear arcs of fire for the new anti - aircraft weapons . An ultimate secondary battery of sixteen 5 " / 38 in dual mounts , sixteen Bofors 40 mm in quadruple mounts and eight single Oerlikon 20 mm was called for by the board in 1941 , although they were not certain the ships could handle the added weight and it would take a large amount of time in dry dock for these modifications to take place . With these concerns , an interim measure of four 1 . 1 in guns was proposed by the board ; however , the gun was not being produced in any great number very quickly , so a second interim solution was implemented . / 50 caliber guns were added to all of the U . S . ' battleships except for " Arizona " and " Nevada " by June 1941 ; these were replaced on the three battleships in the Atlantic by the 1 . 1 in by November — they received them first because they were closer to a war zone . As these modifications were carried out upon the various battleships , much additional weight was added onto the already overweight ships , forcing torpedo bulges to be added so that a decent freeboard could be maintained . These would cost $ 750 , 000 and around three or four months in a dry dock . The King Board suggested that the deck armor be bolstered and 5 in / 38 dual - purpose guns be added , but the Chief of Naval Operations decreed that any major changes such as these had to wait due to the wars raging around the world at the time . The addition of bulges , however , was approved for the " Big Five " , with each ship spending three months in dry dock at the Puget Sound Naval Yard . " Maryland " would be first ( 17 February 1941 to 20 May ) , followed by " West Virginia " ( 10 May to 8 August ) , " Colorado " ( 28 July to 28 October ) , " Tennessee " ( 19 January 1942 to 21 April ) and " California " ( 16 March to 16 June ) . However , the estimates for how long the addition of bulges would take were too low ; Puget Sound believed that they could complete work on " Maryland " in 123 calendar days ( about four months ) — if the work would be given a priority equal to that of s refit and higher than new construction . Only two of the ships had bulges added to them through this program , " Maryland " ( completed 1 August 1941 ) and " Colorado " ( 26 February 1942 ) ; the attack on Pearl Harbor interrupted the refits intended for " West Virginia " and the two " Tennessee " s . The surprise strike did not touch " Colorado " , which was at Puget Sound , and did not hurt " Maryland " very badly ; however , " West Virginia " was severely damaged and needed a major refit at minimum . Little to no major modifications were made to the two active " Colorado " s in the opening months of the U . S . ' s entry into the war ; all of the battleships in the Pacific Fleet had a constant order to be ready to sail within 48 hours in case of a Japanese attempt to invade Hawaii or the West Coast and could not be spared for any major yard work . " Colorado " was hurried through the rest of her refit with the addition of essential items like radar , splinter protection , 14 Oerlikon 20 mm and four 1 . 1 in light anti - aircraft guns ; " Maryland " received a similar treatment later , the only difference being 16 20 mm ' s and no 1 . 1 in . Although tower masts were constructed for " Colorado " and " Maryland " and a majority of the old cage mast s were cut down by the ships ' crews in the beginning of 1942 , the ships could not be spared the time needed to install the new masts . The tower masts were placed into storage and not used until early 1944 . " Colorado " and " Maryland " were greatly needed in the war zone , and as such did not undergo a major refit until 1944 , although minor additions and removals , mainly to the anti - aircraft weaponry , were made in - between . Throughout the war , both ships saw their anti - aircraft battery changed constantly . Beginning in 1942 , they carried eight 5 in / 25 , four quadruple - mounted 1 . 1 in guns , a greatly varying number of 20 mm , and eight . 50 caliber machine guns . In June 1942 , " Colorado " had fourteen 20 mm ; just five months later , this was upped to twenty - two , with thirty - six temporarily approved for a later time . By February 1943 , both " Colorado " and " Maryland " had two more quad 1 . 1 in added ( for a total of 6 ) and forty - eight total 20 mm ; a month later she was given an additional ten . 50 caliber machine guns . November 1943 saw the removal of two of the single - purpose 5 in / 51 , the six quad 1 . 1 in , and a small number of 20 mm ( six in " Colorado " , eight in " Maryland " ) in favor of thirty - two Bofors 40 mm — six quad and two twin . Both ships finally underwent major refits in 1944 . Here the remaining cage masts were taken off in favor of the tower masts , the two twin 40 mm replaced by quads , a quadruple 20 mm added , and a new radar fitted . Although more extensive refits were proposed by Admiral Ernest J . King , including the addition of eight twin 5 in / 38 , more advanced fire control systems , and a second protective deck plating , the Bureau of Ships , after demonstrating what would have to be removed as compensation for the weight added for King ' s ideas , counter - proposed that a smaller reconstruction , like the ones given to the , would be more desirable . However , no action was taken until " Maryland " was struck by a kamikaze aircraft . While undergoing repair , eight twin 5 in / 38 were added , but nothing else ; her conning tower was removed and replaced by a special - treated steel structure to balance the additional weight of the 5 in guns . Ships in class . USS " Colorado " . was the third ship of the United States Navy named in honor of the 38th state . Her keel was laid down on 29 May 1919 by the New York Shipbuilding Corporation of Camden , New Jersey . She was launched on 22 March 1921 and commissioned on 30 August 1923 , Captain R . R . Belknap in command . During her career , " Colorado " was involved in various ceremonies and fleet exercises , and assisted Long Beach residents following an earthquake there in 1933 . In 1937 , she was one of several ships that searched for Amelia Earhart after her plane went missing . " Colorado " was at Puget Sound at the time of the attack on Pearl Harbor on 7 December 1941 . She returned to Pearl Harbor April 1942 . From November 1942 to September 1943 she was stationed in the South West Pacific . In November 1943 , " Colorado " participated in operations against the Japanese during both the Gilbert and Marshall Islands campaign and Mariana and Palau Islands campaign , and she shelled Luzon and Okinawa in advance of the planned amphibious assaults there . Following World War II " Colorado " participated in Operation Magic Carpet before being decommissioned in 1947 . She was sold for scrap in 1957 . USS " Maryland " . was the third ship of the United States Navy to be named in honor of the seventh state . Her keel was laid down 24 April 1917 by Newport News Shipbuilding Company of Newport News , Virginia . She was launched on 20 March 1920 and commissioned on 21 July 1921 , with Captain C . F . Preston in command . During her career she made a goodwill voyage to Australia and New Zealand in 1925 , and transported President - elect Herbert Hoover on the Pacific leg of his tour of Latin America in 1928 . Throughout the 1920s and 1930s , she served as a mainstay of fleet readiness through tireless training operations . In 1940 , " Maryland " changed her base of operations to Pearl Harbor . She was present at Battleship Row along Ford Island during the Japanese attack on Pearl Harbor on 7 December 1941 . Damaged during the attack , " Maryland " reported to the Puget Sound Navy Yard , where she was repaired and modernized . " Maryland " supported the amphibious landings during the Battle of Tarawa , and thereafter participated in the Gilbert and Marshall Islands campaign , the Mariana and Palau Islands campaign , the Battle of Peleliu , the Philippines Campaign , and the Battle of Okinawa . Following the end of World War II " Maryland " participated in Operation Magic Carpet before decommissioning in 1947 . She was sold for scrap in 1959 . USS " Washington " . was the second ship of the United States Navy named in honor of the 42nd state . Her keel was laid down on 30 June 1919 at Camden , New Jersey , by the New York Shipbuilding Corporation . She was launched on 1 September 1921 , but on 8 February 1922 , two days after the signing of the Washington Naval Treaty for the Limitation of Naval Armaments , all construction work ceased on the 75 . 9 % completed dreadnought . The ship was towed out in November 1924 to be used as a gunnery target . On the first day of testing , the ship was hit by two torpedoes and three near - miss bombs with minor damage and a list of three degrees . On that day , the ship had 400 pounds of TNT detonated on board , but she remained afloat . Two days later , the ship was hit by fourteen shells dropped from , but only one penetrated . The ship was finally sunk by the battleships and with fourteen 14 in shells . After the test , it was decided that the existing deck armor on battleships was inadequate , and that future battleships should be fitted with triple bottoms . USS " West Virginia " . was the second ship of the United States Navy named in honor of the 35th state . Her keel was laid down on 12 April 1920 by the Newport News Shipbuilding and Drydock Company of Newport News , Virginia . She was launched on 17 November 1921 and commissioned on 1 December 1923 , Captain Thomas J . Senn in command . Despite a grounding incident early in her career " West Virginia " received high acclaim for gunnery and armor protection , and was involved in exercises to test the defenses of the Hawaiian Islands in the 1930s . On the morning of 7 December 1941 , " West Virginia " sustained heavy damage , but thanks in large part to counter flooding orders the battleship sank at her berth on an even keel , which is similar to that of . Resurrected from the mud on 17 May 1942 , " West Virginia " received enough patchwork to sail for Washington State ; she entered Puget Sound Naval Shipyard in 1942 for repairs and modernization . In July 1944 she emerged from her repairs and overhaul , and set out to rejoin the Pacific Fleet for combat operations . She joined the fleet on the eve of the Philippines Campaign . There she participated in the Battle of Surigao Strait , the last battleship vs battleship duel of World War II , where her new Mk . 8 fire - control radar allowed her to hit the with her first salvo - in the dark - at 22 , 800 yards . In February 1945 " West Virginia " participated in the Battle of Iwo Jima , initially by preinvasion bombardment , and later by callfire support for the ground forces on the island . Her last combat operations were during the Battle of Okinawa ; after the surrender of Japan , she was called upon to participate in Operation Magic Carpet . Decommissioned in 1947 , she was sold for scrapping in 1959 . References . Notes Citations Bibliography . Online sources