The Mississippi class of battleships comprised two ships which were authorized in the 1903 naval budget: and ; these were named for the 20th and 43rd states, respectively. These were the last pre-dreadnought battleships to be designed for the United States Navy, but not the last to be built, because one more ship of a prior design was completed later under the 1904 naval budget. While the quality and technology of the weaponry and armor were first-rate, these ships included a variety of main, intermediate, secondary, and tertiary gun sizes in a predreadnought configuration which became obsolete before the ships were completed.
The first several years of the 20th century were a period of confusion and transition in US naval strategy, tactics, and ship design. The Mississippi class, along with the preceding , were designed based on lessons learned in the Spanish–American War, but while they were under construction, the Russo-Japanese War, war games, and experimentation demonstrated new priorities and concepts which would influence future designs. This was also a period where rapid development of techniques and training in the use of large guns made the inclusion of rapid-fire intermediate and secondary weapons unnecessary. Future US designs would reduce the confusing array of guns sizes in predreadnought battleships and rely on one gun size for the main armament, the "all-big-gun" concept, along with many small guns of a uniform caliber to combat small vessels in close proximity.
The Mississippi-class ships were smaller than the several preceding classes of US battleships. They were designed in an attempt to reduce the rapid growth in the size and cost of U.S. battleships. Also, a theory existed among influential naval leaders, including Dewey and Mahan, that many small battleships could be strategically useful, as were small ships of the line in the 18th and 19th centuries. In essence, the Mississippi-class ships were smaller versions of the preceding Connecticut class with virtually the same armament and armor, but the reduction in length, engine size, and fuel capacity caused them to be slow and short-ranged. Other design compromises caused them to perform poorly in terms of steering, stability, and sea keeping.
These ships served in the US Navy from 1908 to 1914, when they were sold to Greece. Most US service was with the Atlantic Fleet, though these ships did not perform well in fleet operations due to their lower speeds and shorter ranges. The ships were frequently detached for special tasks, including goodwill tours, and Mississippi was used for a time as a seaplane support vessel. Both ships took part in US military interventions in Mexico and the Caribbean, including landing Marines and supporting early air operations.
In 1914, both Mississippi-class ships were sold to Greece, being renamed Kilkis and Lemnos; this was the only sale of functional US battleships to a foreign government. From 1914 to the early 1930s, the ships were active in the Greek Navy, serving mostly in coastal defense and attack roles. In these missions and in the calmer waters of the Mediterranean, their limitations were less pronounced. They served in the Russian Civil War and the Greco-Turkish War. By the mid-1930s, they were relegated to reserve and auxiliary roles, and Lemnos (ex-Idaho) had her guns removed to bolster coastal fortifications. Both were sunk by German aircraft in 1941, and raised in the 1950s to be sold for scrap.
Purpose
alt=Photograph of the U.S. fleet of battleships sailing in line during the world tour known as the Great White Fleet|thumb|The [[Great White Fleet demonstrated America's new naval strength by sailing around the world. Most of these ships were under 10 years old, but were already obsolete.]]
In the early 20th century, the US Navy was growing rapidly. The Navy commissioned its first battleships in 1895, and by the middle of the next decade, Jane's Fighting Ships ranked its battle line second only to the British Navy. However, this rapid growth was not universally supported either within the government or within the Navy. Compromises between powerful groups were frequently necessary to get funding. By the end of fiscal 1902, 10 battleships and two second-class battleships had been commissioned, with seven more battleships authorized but not completed. The per-ship cost had doubled from the $4 million range for the in the 1896 budget to nearly $8 million for Connecticut in the 1902 budget. The Mississippi-class ships would cost just under $6 million each.|group=Note
A division occurred among US naval planners in the early years of the 20th century over whether to have technically superior ships or many less expensive ones, with President Theodore Roosevelt among those supporting the former and Admiral of the Navy George Dewey along with Captain Alfred Thayer Mahan supporting the latter approach. This concept had formed the backbone of the sailing battle fleets of the previous century, but trends in early 20th century naval strategies were making the third-rate concept obsolete.
While Congress had authorized three vessels in the 13,000-long ton range, the design was not specified in the 1903 naval budget. Three approaches were initially considered: a scaled-down version of the preceding 16,000-long ton Connecticut class, five of which had been approved with the 1902 and 1903 budgets; a scaled-up version of the , an 1898 design, three of which were commissioned from 1902 to 1904; and a completely new design which might incorporate new ideas and technology. Interesting adaptations were considered for new designs,
and weight-saving technology could allow increased efficiencies to be achieved from the older Maine class design,
which was closest to the weight goal. Even in the Caribbean, US forces might be farther from their coaling stations than a European power with colonial bases. Beams were typically limited by the width of dry docks.
The quality of guns, armor, ordnance, and design was changing rapidly, so experience could quickly become irrelevant. Combat experience in the Spanish–American War had shown the value of many smaller guns at close range, where the larger guns had been inaccurate.
In the Russo Japanese War of 1904–1905, just six years later, decisive effects were obtained at long ranges, well beyond the effective limits of ordnance.
Main batteries
Recent American designs had continued to include large primary batteries of either or guns, along with several intermediate 8-inch guns for faster fire in closer combat with armored vessels. The lighter intermediate guns were considered valuable for penetrating upper-level armor, where the heavy guns were more effective on the main belt and heavy turrets. The former were likely to diminish the fighting ability of the opponent, while the latter were more likely to sink her.
Earlier US battleships had used 13-inch guns with black powder propellant; the 1898 design of the Maine class used more powerful but smaller 12-inch guns using smokeless powder, giving a greater velocity and flatter trajectory. The 12-inch rifles available in 1904 had a range of , about double the range of the black powder main armament used in the Spanish–American War. These were considered an excellent compromise between weight and firepower, since limitations in gunnery control made longer-range guns impractical. The contemporary consideration was not whether to go larger, but whether to go with more. In 1902, naval officers, with the backing of President Theodore Roosevelt, began to develop superior fire control techniques and equipment. The development of better spotting and range finders led to improvements in range capacity and accuracy. At the same time, superior training and systems significantly reduced the time required to load and fire the large guns, from three minutes to one minute.
Intermediate 8-inch guns had been discontinued in 1896 with the Illinois class, but based on experience in the Spanish–American War in 1898, 8-inch/45-caliber guns were reinstated in the Virginia class and continued in the Connecticut class. Typically, these were carried in two-gun turrets, but the placement of the turrets had been inconsistent in prior designs; in two prior designs, the turrets for the 8-inch guns were superimposed over the turrets for the 12/13-inch guns (see and classes). Some designers felt that 8-inch guns were redundant to the faster firing 7-inch/45-caliber guns carried in casemates. Others argued that increases in the rate of fire and accuracy of the 12-inch guns eliminated the need for any smaller guns in the main battery.
Secondary batteries
In 1903, secondary batteries were typically considered to be a combination of torpedo defense—defense against smaller boats armed with torpedoes, such as torpedo boats or destroyers—and weapons to attack the lightly armored upper structures of capital ships.
Recent US warships had mounted a combination of a few 7-inch or 6-inch guns and many smaller guns in the to range (6-pounder to 12-pounder in the traditional terms). The larger of these guns were typically protected in casemates and the smaller ones open on the deck or in lightly protected casemates.
A fast-firing 7-inch/45-caliber gun had been adopted with the previous battleship class to replace earlier 6-inch guns; these brought a significant improvement in ballistics, expanding the potential beyond torpedo defense, but came with drawbacks. Various opinions on the best combination of guns existed: all 8-inch, all 7-inch, or a mix.
Though considered to be quick-firing, the propellant for 7-inch guns was loaded in bags, making them slower than contemporary 6-inch guns. The Navy considered these to be excellent for the intended role; however, in World War I North Atlantic convoy duty, the disadvantages in seakeeping outweighed the utility; they were removed from battleships remaining in US service in 1918.
Beginning with the Maine-class vessels, commissioned in 1902, the 50-caliber gun (12-pounder) was used on most U.S. battleships as an antitorpedo-boat weapon. These and smaller weapons are frequently referred to as tertiary guns. This role was filled back to the earliest U.S. battleships, including the Texas and first Maine, by the 6-pounder . Most 3-in guns were removed from U.S. battleships before combat operations in World War I.
Competing designs
The future of battleship weaponry was at a crossroads. Opinions varied among top naval leaders; some U.S. naval leaders were discussing the all-big-gun concept in parallel with the British , while other designers felt that the torpedo would completely replace the gun, and battleships should become heavily armored launch platforms. Other proposals included even more but smaller primary guns, in the size to save on weight. In 1903, analysis of war games had determined that one battleship with 12 11-inch or 12-inch guns, in a hexagonal turret placement, could be superior to three conventional battleships in individual actions.
Other analysis suggested that in fleet actions, only broadsides were effective, thus maximizing the number of centerline guns was the most efficient approach. While neither approach was incorporated in the Mississippi class, the centerline maximum broadside concept was followed in all subsequent U.S. battleship designs.
Final design
In the end, these ships were built with main batteries identical to the Connecticut class, while reducing by four guns the secondary 7-inch battery, omitting eight of the tertiary 3-inch guns, and sacrificing two torpedo tubes. Subsequent designs would eliminate the 7-inch batteries completely, and most of the 3-inch guns were removed from other battleships before combat in World War I, so in this respect, the design did not suffer by comparing forward.
The remaining eight 7-inch 45-caliber guns were distributed four per side, in casemates on the side of the ship, below the main deck.
Four 50-caliber guns were mounted in the upper casemates (on the main deck), two per side, behind of armor plate. Another two, one per side, were mounted in blister casemates on the gun deck, near the bow. The remaining eight guns were on open mounts on the upper deck, the bridge, and other deck spaces. Two submerged torpedo tubes were fitted on the broadside, near the bow of the ships. Each ship carried a total of 13 torpedoes.
Armor
thumb|alt=cross section of a battleship hull showing armored sections with approximate thicknesses: The thickest armor is at the waterline, tapering up to the lease on the top deck.|left|Simplified drawing of armor scheme for early 20th century U.S. battleships
Prior to the mid 1870s, armor was made of wrought iron plate, sometime backed with wood. In the 1870s, compound armor was developed, where a hardened steel face was cemented to a softer iron backing, which prevented cracking. During the late 1880s, nickel-steel armor was devised and in 1890, the Harvey process was developed, where a nickel-steel plate was treated with carbon and hardened in cold water. This process allowed one homogeneous steel plate to have both a hard surface and a softer back which was less likely to crack. During the 1890s, Krupp armor further refined the Harvey process by including additional metals in the alloy and developing a system where the hardening process penetrated more deeply into the plates. Tests showed that of Krupp armor was equal to of Harvey armor, of compound armor, and of wrought iron plate, while in thinner plates, Harvey armor was basically equal to Krupp.
The Mississippi-class ships used a combination of Harvey- and Krupp-style armor (American-made), with much of the side armor backed with teak wood, consistent with other U.S. capital ships of the decade. The amount of armor and its strength was consistent with the preceding Connecticut class and in some cases was more complete in coverage and was thicker, especially compared to the earliest ships in that series. The belt armor was thinner, compared to , but longer, compared to , despite the Mississippi class being shorter, compared to . The primary turret armor was thicker by an inch— thick—as opposed to on the USS Connecticut.
Machinery
alt=Animated triple expansion engine showing pistons moving under the force of steam, which goes from cylinder to cylinder with each larger in the progression|thumb|right|A triple-expansion engine uses steam three times.
When these ships were designed, the older technology of reciprocating steam engines was slowly being replaced by the newer technology of steam turbine propulsion. While turbines generally meant more speed, they were less fuel-efficient and limited the range of the ships unless more fuel could be stored. Early Dreadnought designs, which were in simultaneous development with the Mississippi class, used primitive direct-drive turbines. The U.S. Navy was slow to fully adopt turbines, and only used them exclusively in battleship production when indirect transmissions became refined (gear reduction or turbo-electric). Several subsequent battleship classes were built where otherwise identical vessels had different types of engines (for example, the and es).
Mississippi and Idaho were equipped with two-shaft vertical triple-expansion steam engines, which drove two propellers. These were reciprocating engines where the steam was used multiple times (triple expansion) for greater efficiency. Steam was provided by eight Babcock & Wilcox boilers. Their engines were rated at , which produced a top speed of .
The ships carried of coal in purpose-designed coal bunkers and up to another of coal could be stored in voids in the sides of the hull.
General characteristics
thumb|Plan and profile drawing of the Mississippi class
The final design was a scaled-down version of the preceding Connecticut class. By comparison, these ships were a knot slower and had a lower freeboard, so they did not perform as well in heavy seas. The two Mississippi-class ships were long overall, had a beam of and a draft of . The ships were designed to displace at normal displacement and up to at full combat load. Each ship had a crew of 34 officers and 710 enlisted men.
The World Cruise of 1907–1909 tested the seakeeping of the U.S. designs. Even the earlier designs, including the Connecticut class with their higher freeboard, carried their secondary armament too close to the waterline.
The ships initially carried a pole mast above the conning tower, though shortly after commissioning, both ships had lattice masts added aft, and in 1910, the forward masts were also replaced with lattice masts.
The reduced length while retaining the same beam as the prior Connecticut class resulted in a disadvantageous length-to-beam ratio, causing reduced performance relative to that class. Not only was their top speed a knot slower, but also their economical speed was reduced by one and half knots. They also had 25% less coal storage, further reducing their operating range.
The Mississippi ships had poor seakeeping qualities, making them poor gunnery platforms underway in Atlantic waters. Their motion was irregular, and their low length-to-beam ratio caused excessive rolling and pitching, which made it difficult to keep the guns on target. The reduced length, significantly cut away from the aft, made it difficult to keep the ships on a consistent course, even in smoother waters.
Ships
{|class="wikitable plainrowheaders"
|+ Construction data
|-
! scope="col" | Name
! scope="col" |
! scope="col" | Builder
! scope="col" | Laid down
! scope="col" | Launched
! scope="col" | Commissioned
! scope="col" | Fate
|-
! scope="row" |
|
| rowspan=2 | William Cramp & Sons
| style="text-align: right;" | 12 May 1904
| style="text-align: right;" | 30 Sep 1905
| style="text-align: right;" | 1 Feb 1908
| Sold to Greece, 1914; sunk by German aircraft, Apr 1941; sold for scrap, 1950s
|-
! scope="row" |
| BB-24
| style="text-align: right;" | 12 May 1904
| style="text-align: right;" | 9 Dec 1905
| style="text-align: right;" | 1 Apr 1908
| Sold to Greece, 1914; sunk by German aircraft, Apr 1941; sold for scrap, 1950s
|}
USS Mississippi (BB-23)
alt=Photograph of the USS Mississippi partially completed.|thumb|USS Mississippi under construction, in 1907
The second Mississippi (Battleship No. 23) was laid down in 1904, launched in 1905, and commissioned in early 1908, With the outbreak of fighting in Mexico in April 1914, Mississippi sailed to Veracruz, arriving with the first detachment of naval aviators to go into combat. In June 1914 she returned to Hampton Roads, where in July she was decommissioned and transferred to the Greek Navy.
Mississippi was renamed for the crucial battle of the Second Balkan War, while Idaho became in honor of a victorious naval battle over the Turkish Navy during the First Balkan War. Though their service was uneventful, these ships served to balance German capital ships which were acquired by rival Turkey.
The design limitations and poor seakeeping tendencies were not as critical in that strategic environment and the calmer seas of the Mediterranean. U.S. Ambassador to Turkey Henry Morgenthau, Sr. wrote, "Those battleships immediately took their places as the most powerful vessels of the Greek Navy, and the enthusiasm of the Greeks in obtaining them was unbounded."|group=Note
Defections by units of the Greek Navy to the Venizelist factions provoked a Royalist purge of Venizelist officers and men from the Greek Navy. French Admiral Fournet, the Commander in Chief of the Allied Squadron, perceived the Greek fleet as a menace to the Entente powers in the Aegean. He delivered an ultimatum to the Greeks to sequester the small ships and disable the large ones. On 19 October 1916, the breech blocks, munitions, and torpedoes were removed from Lemnos and Kilkis. At the same time, the crews were reduced to one-third of normal size.
In June 1917, Greece was reunified under Venizelos and declared war against the Central Powers. Restoration of the Greek Navy was slow due to British and French disagreements and the difficulty in guaranteeing the officers and crews would support a war against the Central Powers. When France returned the ships, Lemnos and Kilkis took part in Allied operations in the Aegean. The greatest Allied need in the Mediterranean was for antisubmarine units, thus battleships were not a priority.
After World War I, both ships saw action in 1919 under the command of Rear Admiral G. Kakoulidis, RHN, when the Greek Navy took part in the Allied expedition in support of Denikin's White Armies in Ukraine.
Later careers
The ships were also active in the operations of the Greco-Turkish War in Asia Minor from 1919 to 1922. On 15 May 1919, 20,000 Greek soldiers landed in Smyrna and took control of the city and its surroundings under cover of the Greek, French, and British navies. Lemnos was the flagship to the Second Fleet, based in Smyrna, under Rear Admiral G. Kalamidas; her mission was surveillance of the Black Sea, Dardanelles, and Asia Minor coasts. The wrecks were refloated and sold for scrap in the 1950s.