text:
Tag Archives: battle of the philippine sea
Short, Squat, Powerful and Well Protected: The South Dakota Class Battleships
I am still on my holiday from writing about the novel Coronavirus 19 and President Trump and his Administration's incompetent response to it. It is a response that has already claimed 87,000 American lives, and every day more damning evidence shows the results for the President's use of it for political purposes, almost all of which are backfiring as much as his malfeasance and willingness to see Americans die by the tens of thousands to maintain his cloud-cuckoo-land fantasy that this will go back to normal as if by magic. But, I won't go any farther tonight on that tonight.
I was so inflamed about what was happening earlier today I decided that it was best to continue my series on the battleships designed and built by the British, French, Germans, Italians, and Americans from after the Battleship Holiday mandated by the Washington Naval Treaty, and the restrictions of the London Naval Treaty. The Germans were not signatories to these treaties as they were already under the much more severe provisions of the Treaty of Versailles, until the Hitler regime began to clandestinely violate it in 1934, and publicly in 1935. The British signed at bilateral naval accord with Germany in June of 1935, which the Germans renounced in 1938 in order to build a fleet of battleships that Hitler believed would allow him to achieve naval parity or superiority over the British, which he renounced in 1938 during the Czechoslovakia crisis.
This is the fifth and last in a series of articles about the battleships built under the provision of the Washington and London Naval Treaty limitations in the 1930s. I am not including the ships which were already in service or completed in the immediate aftermath of the Washington Treaty. That treaty required the British to scrap 23, the Americans 30, and Japanese 17 Battleships or Battlecruisers to comply with the treaty. Some were allowed to be converted to Aircraft Carriers, and some demilitarized to serve as training or target ships.
This series looks at the modern battleships built by the future World War II combatants between 1932 and 1939. This article covers the American South Dakota Class. Previous articles dealt with the British Royal Navy's King George V Class, The German Kriegsmarine Scharnhorst Class, the Italian Reginia Marina's Vittorio Veneto Class, the United States Navy's North Carolina Class, and the French Dunkerque and Richelieu Classes.The German Bismarck, Japanese Yamato, British Vanguard and American Iowa classes will be covered in a subsequent series.
I think that I will also go back and deal with various classes of ships that were allowed to be kept after the Washington Naval Treaty. These included two of the three partially built American Colorado Class, the two ship British Nelson Class, and the second of the Japanese Nagato Class, the Mutsu; and the battleships and battlecruisers that were completed as Aircraft Carriers by the United States, Britain, Japan, and France. From there I could move on and write about and the new battleships and battlecruisers planned or under construction at the time the treaty came into effect, the ships that had they been built would have launched a major naval arms race in the 1920s, something that few nations could have afforded, especially Great Britain. I think I will even go back to the Dreadnoughts and Battlecruisers of the First World War. Of course there are a lot of them, so I will probably focus on the ships that continued serving through the Second World War. I might even delve into the German H type battleships which were more fanciful than realistic, only satisfying the need of Hitler for nothing but the biggest, the American Montana Class, the British HMS Vanguard, the French Alsace Class, and the Japanese A-150 or Super Yamato's.
Since there is much disagreement about which of the ships that I have written about in this series, I may try to do a comparison to determine which was the best of these classes in the categories, of armament, speed and range, armor protection, reliably, and performance in combat. One has to remember that these were the first battleships built by their respective navies since the First World War, each was built under the constraints imposed by the naval treaties, and their influenced by the developments of potential opponents and the changing world situation. In some cases sacrifices were made on each design due to expediency and the need to get them to the fleet.
As the world edged closer to war in the late 1930s the U.S. Navy followed up its decision to build the two ship North Carolina class battleships with additional fast battleships. Initially the General Board wanted two additional North Carolina's the Chief of Naval Operations, Admiral William H. Standley wanted a different design, which may have created the toughest and best of the battleships in this series. Compared to the other battleships built in this era, the South Dakota Class was short, fat, a bit slower, but was superbly protected with a well designed armored citadel, excellent main, secondary, and anti-aircraft batteries, and superior radars, fire direction systems and combat operation centers. They demonstrated a knack for survival as well as an ability to inflict damage, as was shown by the South Dakota and Massachusetts.
USS South Dakota BB-57 in 1943
Design work started in 1937 and several designs were proposed in order to correct known deficiencies in the preceding North Carolina class to include protection and the latest type of steam turbines. As in the North Carolina's the Navy struggled to find the optimal balance between armament, protection and speed. In the end the Navy decided on a shorter hull form with greater beam which necessitated greater power to maintain a high speed. The armor protection was maximized by using an interior sloped belt of 12.2 inch armor with 7/8" STS plates behind the main belt which made the protection the equivalent to 17.3 inches of vertical armor. The Belt continued to the bottom of the ship though it was tapered with the belt narrowing to 1 inch to provide addition protection against plunging fire which struck deeper than the main belt. As an added feature to protect against torpedo hits a multi-layered four anti-torpedo bulkhead system was included, designed to absorb the impact of a hit from a 700 pounds of TNT.
In order to accommodate the machinery necessary to provide the desired speed of 27 knots on the shorter hull the machinery spaces were rearranged. The new design placed the boilers directly alongside the turbines with the ship's auxiliaries and evaporators also placed in the machinery rooms. Additional design changes made to save space included making the crew berthing areas smaller. This included that of officers as well as the senior officers and shrinking the size of the galley's and the wardroom from those on the North Carolina's. The resultant changes allowed the ships to achieve the 27 knot speed, improved protection and carry the same armament of the North Carolina's within the 35,000 treaty limit.
Two ships of the design were approved and with the escalator clause invoked by the Navy two more ships were ordered all with the nine 16" gun armament of the North Carolina's. The leading ship of the class the South Dakota was designed as a fleet flagship and in order to accommodate this role two of the 5" 38 twin mounts were not installed leaving the ship with 16 of these guns as opposed to the 20 carried by the rest of the ships of the class. The final design was a class of ships capable of 27.5 knots with a range of 17,000 miles at 15 knots mounting nine 16" guns with excellent protection on the 35,000 tons and full load displacement of 44,519 tons.
The lead ship of the class the USS South Dakota BB-57 was laid down 5 July 1939 at New York Shipbuilding in Camden New Jersey, launched on 7 June 1941 and commissioned on 20 March 1942. Following her commissioning and her shakedown cruise South Dakota was dispatched to the South Pacific. Soon after her arrival she struck a coral reef at Tonga which necessitated a return to Pearl Harbor for repairs.
When repairs were complete she was attached to TF 16 escorting the USS Enterprise CV-6 during the Battle of the Santa Cruz Islands on 26 October 1942. During the battle she was credited with shooting down 26 Japanese aircraft but was struck by a 500 lb bomb on her number one turret which caused no damage.
The Dent in South Dakota's Number Three Turret from a hit from a 14" Shell from Kirishima
She joined TF-64 paired with the battleship USS Washington during the Second Naval Battle of Guadalcanal on14-15 November 1942. During the action South Dakota suffered a power outage and was hit by over by a minimum of 26 enemy shells, and possibly up to 40. At least one of a 14" shell from Kirishima, 18 8" shells from the Heavy Cruisers, 6 6" shells from from Japanese light cruisers, and at least one 5" shell from a destroyer. The damage was superficial, once her power was restored much of the damage was repaired ship's crew. The shellfire knocked out three of her fire control radars, her radio and main radar set which were also repaired.
Three of the escorting destroyers, USS Preston, USS Walke, and USS Benham were sunk or mortally wounded, and USS Gwin was damaged.destroyers were also lost but the Washington mortally wounded the fast battleship Kirishima and destroyer Ayanami which were scuttled the next day and damaged the heavy cruisers Atago and Takao.
South Dakota returned to New York for repairs which completed in February 1943. She joined the carrier USS Ranger CV-4 for operations in the Atlantic until April when she was attached to the British Home Fleet. She sailed for the Pacific in August 1943 and rejoined the Pacific Fleet in September. The battleship joined Battleship Divisions 8 and 9 and supported the invasion of Tarawa providing naval gunfire support to the Marines.
South Dakota spent the rest of the war was spent escorting carriers as well as conducting bombardment against Japanese shore installations. She participated in almost every action of the U.S. drive across the Central Pacific. She was struck by a 500 pound bomb during the Battle of the Philippine Sea that destroyed several anti-aircraft mounts and killed 26 of her crew.
A Photo taken from South Dakota while anchored in Tokyo Bay with Mount Fuji in the Background
South Dakota was present at the Japanese surrender in Tokyo Bay and returned to the United States in 1945. She was decommissioned and placed in reserve on 31 January 1947. She was stricken from the Naval Register on 1 June 1962 and sold for scrap in October of that year. Various artifacts of this gallant ship to include a propeller, a 16" gun and the mainmast are part of the USS South Dakota Memorial Park in Sioux Falls South Dakota. 6,000 tons of armored plate were returned to the U.S. Atomic Energy Commission for use in civilian nuclear programs and a second screw is displaced outside the U.S. Naval Museum in Washington D.C. She received 13 battle stars for World War II service.
South Dakota also had the dubious distinction of having the youngest sailor of the war 12 year old Calvin Graham who confessed lying about his age to the Gunnery Officer, LT Sergeant Schriver. Graham was court-martialed and given a dishonorable discharge spending 3 months in the ship's brig before he was able to be returned to the United States where just after his 13th birthday he entered 7th grade. Shriver was wounded at Guadalcanal and was awarded the Purple Heart. He left the Navy in in 1945 as a Lieutenant Commander. He later became the Brother in law of John F. Kennedy, and the first Director of the Peace Corps, and became the the running mate of Senator George McGovern in the 1972 Presidential Election, to Richard Nixon and Spiro Agnew.
USS Indiana BB-58 Bombarding Japan in 1945
The second ship of the class the USS Indiana BB-58 was laid down at Newport News Naval Shipyard on 20 November 1939 launched on 21 November 1941 and commissioned on 30 April 1942. She served throughout the Pacific War by serving with the fast battleships of Vice Admiral Willis Lee's TF-34, escorting carriers during major battles such that the Battle of the Philippine Sea or as it is better known the Marianas Turkey Shoot. She returned to the United States for overhaul and missed the Battle of Leyte Gulf but served at Iwo Jima, Okinawa and operations against the Japanese home islands. During the beginning of the Marshall Islands campaign Indiana received her heaviest damage. During night operations with a carrier task group she turned in front of USS Washington. A collision ensued which caused heavy damage to Indiana, including the loss of nearly 200 feet of her armored belt. The collision took off about 20 feet of Washington's bow which remained imbedded in the Indiana until she was repaired. Washington also required a return to the United States for repairs.
Following the war she was decommissioned in 1947 and sold for scrap in September 1963. A number of her relics are preserved at various locations in Indiana and her prow and mainmast are centerpieces of a display at the University of Indiana's football stadium. Much of her armor was provided to the U.S. Atomic Energy Commission for use in civilian programs.
USS Massachusetts BB-59 in January 1946 in the Puget Sound
The third ship of the class the USS Massachusetts BB-59 was laid down on 20 July 1939 at Bethlehem Steel Corporation Fore River Yard in Salem Massachusetts and launched on 23 September 1941 and commissioned on 12 May 1942. After her shakedown cruise she was assigned to the Atlantic Fleet where she took part in Operation Torch, the Allied invasion of French North Africa. During the operation she engaged French shore batteries, damaged the battleship Jean Bart and sank 2 cargo ships and along with the heavy cruiser Tuscaloosa sank the destroyers Fougueux and Boulonnais and the light cruiser Primauguet.
Following her assignment in the Atlantic she sailed for the Pacific where she began operations in January 1944. She took part in almost every major operation conducted by the Pacific Fleet escorting the Fast Carrier Task Forces and operating as a unit of TF-34 the Fast Battleship Task force including the Battle of Leyte Gulf. She ended the war conducting operations against the Japanese home islands. She was decommissioned in 1947 and stricken from the Naval Register on 1 June 1962.
USS Massachusetts BB-59 at Battleship Cove, Fall River Massachusetts
She was saved from the fate of Indiana and South Dakota as the people of Massachusetts with the assistance of schoolchildren who donated $50,000 for her renovation and preservation as a memorial. She became that in 1965 at Battleship Cove in Fall River Massachusetts and she remains there designated as a National Historic Landmark. During the naval build up of the 1980s much equipment common to all modern battleships was removed for use in the recommissioned battleships of the Iowa class.
The final ship of the class the USS Alabama BB-60 was laid down on 1 February 1940 at Norfolk Naval Shipyard. She was launched on 21 February 1942 and commissioned 16 August 1942. Following her shakedown cruise and initial training off the Atlantic coast she joined the repaired South Dakota and operated as part of TF 22 attached to the British Home Fleet.
She conducted convoy escort operations, participated in the reinforcement of Spitsbergen and in an operation which attempted to coax the German battleship Tirpitz out of her haven in Norway. Tirpitz did not take the bait and Alabama and South Dakota returned to the United States in August 1943.
Following a brief refit she and South Dakota transited to the Pacific were the trained with the fast carriers. She took part in the invasion of the Gilberts taking part in Operation Galvanic against Tarawa and the Army landings on Makin Island.
As 1944 began Alabama continued her operations with the fast carriers of TF-38 and the fast battleships of TF-34. She took part in operations against the Marshalls and took part in the invasion of the Marianas Islands and the Battle of the Philippine Sea, the Great Marianas Turkey Shoot. From there she supported the invasion of Palau and other islands in the Caroline Islands followed by operations against New Guinea and the invasion of the Philippine and the Battle of Leyte Gulf before returning to the United States for overhaul.
Chief Petty Officer Bob Feller
Alabama returned to action during the invasion of Okinawa and in shore bombardment operations against the Japanese Mainland. When the war ended the Alabama had suffered no combat deaths and only 5 wounded following the misfire of one of her own 5" guns earning her the nickname of "Lucky A." Hall of Fame pitcher Bob Feller served as a Chief Petty Officer and gun mount captain on Alabama during the war.
She was decommissioned on 9 January 1947 and stricken from the Naval Register on 1 June 1962. The people of the State of Alabama formed the "Alabama Battleship Commission" and raised $1,000,000 including over $100,000 collected by schoolchildren to bring her to Alabama as a memorial. She was turned over to the state in 1964 and opened as a museum on 9 January 1965. She was declared a National Historic Landmark in 1986. She has been used as a set in several movies and continues to serve as a museum preserving the legacy of the men that served aboard her and all of the battleship sailors of World War II.
another thing about the South Donata Class was that their design was evident in the rebuilding of the USS California, USS Tennessee, and USS West Virginia when they were completely modernized after Pear Harbor.
USS West Virginia after her complete modernization after being sunk at Pearl Harbor
In the 1950s a number of proposals were considered to modernize the ships of the class to increase their speed to 31 knots using improved steam turbines or gas turbines. The Navy determined that to do this would require changes to the hull form of the ships making the cost too prohibitive. The ships were certainly the best of the treaty type battleships produced by any nation in the Second World War. The damage sustained by South Dakota at the Second Naval Battle of Guadalcanal would have not only put most battleships of her era out of action but might have caused enough damage to sink them. Their armament was equal or superior to all that except the Japanese Yamato Class and their protection was superior to most ships of their era, and it was was exceptional, as was evident by the damage sustained by South Dakota.
Alabama as a Museum Ship
It is good that both the Massachusetts and the Alabama have been preserved as memorials to the ships of the class, their sailors and the United States Navy in the Second World War. Because of the efforts of the people of Massachusetts and Alabama millions of people have been able to see these magnificent ships and remember their fine crews. Both have hosted reunions of their ships companies since becoming museum ships and with the World War Two generation passing away in greater numbers every day soon these ships as well as the USS Texas, USS North Carolina, USS Missouri, USS New Jersey, USS Wisconsin aUSS Iowa which stricken from the Naval Register awaits an uncertain fate as a resident of the "Ghost Fleet" in Suisun Bay California. No other nation preserved any other dreadnought or treaty battleship thus only these ships remain from the era of the Dreadnought. I so much wish that the British had preserved one of the King George V ships, or maybe the mostend celebrated Royal Navy Battleships of both World Wars, the HMS Warspite had been preserved. I also regret that none of the survivors of the attack on Pearl Harbor were preserved, nor any of the standard battleships of the Nevada, Pennsylvania, New Mexico, California, or Colorado Classes.
I am fortunate. I have been able to go aboard the North Carolina, Alabama, Texas, and Wisconsin, as well as a number of the surviving aircraft carriers, destroyers, and submarines preserved in the United States. However, too few, especially the ships which bore the brunt of the war like the carrier USS Enterprise were never saved, despite the pleas of men like Admiral William "Bull" Halsey.
I habe also been able to visit ships like the USS Constitution, USS Constellation, Clipper ship Star of India, the Japanese Battleship Mikasa, the USS Nautilus, the German Tall Ship Gorch Fock II, and so many more, but I still have a bucket list of ships I want to visit in the United States, Canada, Great Britain, Germany, Greece, Sweden, Russia, France, Australia, Italy, Turkey, Japan, and Finland.
With those pipe dreams in mind, I wish you all the best. Until tomorrow when I decide to weigh in again on novel Coronavirus 19 and the crisis being fostered by the Trump Administration in this country; please be safe. Don't do dumb things like going into crowded places with few people wearing masks and the vast majorly of people not adhering to social distancing. Even if other people decide to be stupid and put others and well as their own lives at risk, don't be like them. I speak this from the heart and I don't care if someone disagrees with my politics, faith, or social commentary, I would prefer that they not die or through their stupidity and arrogance get other people sick or die. Darwin is not Kind when it comes to the stupidity and arrogance of people regardless of the race, ethnicity, faith, ideology, political leanings, social standing, economic position, or nationality.
I don't care if people agree with me or not, but don't do dumb things. This may sound harsh but I tend to speak from my heart when lives and civilization itself are at stake. But please remember the words of Robert Henlein:
"Stupidity cannot be cured. Stupidity is the only universal capital crime; the sentence is death. There is no appeal, and execution is carried out automatically and without pity."
Filed under Foreign Policy, historic preservation, History, imperial japan, Military, Navy Ships, nazi germany, Political Commentary, US Navy, World War II at Sea, world war one, world war two in europe, world war two in the pacific
Tagged as battle of the philippine sea, battle of the Santa Cruz islands, battleship cove fall river massachusetts, bismarck class, bismark, bob feller, colorado Class, dunkerque class, george mcgovern, hms nelson, HMS Rodney, hms vanguard, HMS Warspite, ijn kirishima, ijn mutsu, ijn nagato, iowa class, king george v class, london Naval treaties, nagato class, nelson class battleship, north carolina class, richelieu class, robert henlien, scharnhorst class, seargent shriver, second naval battle of guadalcanal, south dakota class, treaty of versailles, uss california, uss enterprise cv-6, uss indiana bb-57, uss iowa, uss massachusetts, Uss South Dakota bb 57, uss tennessee, USS Texas, uss washington bb-56, uss west virginia, Vittorio Veneto class, washington naval treaty, yamato class
A Senseless and Fanatical Sacrifice: Kamikazes Enter the War at Leyte Gulf
USS St Lo exploding after being hit by a Kamikaze
Again I am taking some time off from current events as fast as they are moving, and I am posting edited articles about Battle of Leyte Gulf. The battle was the largest naval battle every fought and harborslessons that redound to our day. This article deals with the first use of Kamikaze aircraft whose pilots would attempt to dive into Allied warships, committing suicide rather than attempting to bomb a ship and return home.
In an age where suicide bombers and attackers do such things it is important to remember that this is not new. The Kamikaze pilots for the most part brainwashed by the Samurai ideology which had been drilled into them since they were children. One who survived because of engine failure and did not get a second chance told the BBC:
"Common sense says you only have one life," he says, "so why would you want to give it away? Why would you be happy to do that? But at that time everyone I knew, they all wanted to volunteer. We needed to be warriors to stop the invasion from coming. Our minds were set. We had no doubt about it."
While most Kamikaze pilots hated that ideology, some did not. Regardless, such a mentality is true of many fanatical idealists and terrorists even today. Such men and women span the religious and ideological spectrum. That is the truth, and it is profoundly depressing. Human nature being what it is means that there will be many more like them, the terrorists of September 11th 2001 were little different than the Kamikazes, but instead of the Bushido creed of the Samurai, it was a fanatical belief in Jihad.
In 1944 one of the leading Japanese Naval aviators, Admiral Takijirō Ōnishi wrote:
"In my opinion, there is only one way of assuring that our meager strength will be effective to a maximum degree. That is to organize suicide attack units composed of A6M Zero fighters armed with 250-kilogram bombs, with each plane to crash-dive into an enemy carrier…"
It was a tactic born of desperation but one that fit in well with the philosophy of Bushido. After the Battle of the Philippine Sea, the "Marianas Turkey Shoot" in June 1944 and the slaughter of land based Japanese Naval and Army air forces based in Formosa in September of that year Japanese leaders began to look to a tactics born of desperation but which fit their Bushido based ethos of sacrifice.
Lt. Yukio Seki
Suicide attacks were nothing new to the Japanese, but until October 1944 they were tactics decided on by individuals who saw no alternative to the choice. In October 1944 that calculus changed, instead of individuals or isolated units which had no hope of victory conducting suicide attacks, commanders decided to employ suicide attackers as a matter of course.
When the American forces invaded the Philippines Admiral Takijirō Ōnishi was commander of the First Air Fleet based in the Northern Philippines. He was not a fan of Kamikaze tactics and viewed them as heresy. However after the slaughter of the reconstituted Naval Air Force at the Battle of the Philippine Sea he reluctantly changed his mind. I say reluctantly based on his previous views and because after he committed ritual suicide following the Japanese surrender he apologized to the estimated 4000 pilots that he sent to their death and their families.
Admiral Ōnishi
But in October 1944 with Japan reeling from defeats in the Pacific and its supply route for oil and other raw materials threatened desperation was the order of the day.
The 201st Navy Flying Corps based out of Clark Field near Manila was the major land based Japanese Naval Air Force unit in the Philippines. Among its pilots was a young Naval Officer and Aviator named Lt. Yukio Seki. Seki was a graduate of the Japanese Naval Academy at Eta Jima and was recently married. He was not an ideologue or believer in suicide attacks. When questioned by a reporter before his squadron launched the first Kamikaze attacks he remarked to Masashi Onoda, a War Correspondent :"Japan's future is bleak if it is forced to kill one of its best pilots. I am not going on this mission for the Emperor or for the Empire… I am going because I was ordered to!"
On October 25th 1944 Seki led his group of 5 A6M2-5 Zero fighters, each carrying a 550 pound bomb took off and attacked the Escort Carriers of Rear Admiral Clifton Sprague's "Taffy-3." The five pilots all died in their attacks but two damaged the USS Kalinin Bay and USS Kitkun Bay while two aircraft, one believed to be Seki's hit the USS St Lo causing mortal damage which sank that ship in less than half an hour with the loss of over 140 sailors.
The attacks of Seki's small squadron were a harbinger of what was to come. Over the next 10 months over 4000 Japanese pilots would die in Kamikaze attacks against US Navy and Allied Naval units. Numbers of ships destroyed or damaged by Kamikazes are debated by some historians believe that 70 US and Allied ships were sunk or damaged beyond repair and close to 300 more damaged. 2525 Imperial Japanese Navy pilots and 1387 Imperial Army pilots died in Kamikaze attacks killing almost 5000 sailors and wounding over 5000 more.
Another pilot, who did not swallow the propaganda was Lieutenant Ryoji Uehara. He wrote his mother before his final mission:
"Tomorrow, one who believes in democracy will leave this world, he may look lonely but his heart is filled with satisfaction. Fascist Italy and Nazi Germany have been defeated. Authoritarianism is like building a house with broken stones."
Admiral Ōnishi who made the decision to make Kamikazes a part of Japan's offensive strategy in 1944 appeared to regret that decision. In his suicide note he urged young Japanese to rebuild the country and seek peace with all people and offered his death a penance for the nearly 4000 pilots he sent to their deaths. Accordingly when he committed ritual suicide (seppuku) he did so alone, with a second to finish the job and died over 15 hours after disemboweling himself.
A Final Toast
The Kamikaze campaign did not alter the course of the war, but it did introduce a new dimension of terror and misguided sacrifice. Despite the propaganda of the ideologues who urge men and women to undertake suicide missions, there is no honor for those that do so. I do pray that one day war will be no more and that even though I expect war to remain part of our world until longer after my death that nations, peoples or revolutionary groups will no longer send their best and brightest to certain death.
Filed under culture, ethics, faith, History, Military, Political Commentary, racism, Religion, suicide, World War II at Sea, world war two in the pacific
Tagged as 201st Naval Flying Corps, admiral onishi, battle of leyte gulf, battle of the philippine sea, bushido, Clark field, Japanese Right Wing, kamikazes, Masashi onada, Okinawa campaign, Royoji Uehara, Samurai, suicide attacks, terrorism, uss kalinin bay, uss kitkun bay, uss st lo, Yukio Seki
Wings of Gold: U.S. Navy Carrier Aircraft 1941-1945
F4F-4 Wildcat of VF-41 in 1942
In 1941 with war raging in Europe and with the Japanese continuing their war in China and occupying French Indo-China the United States rushed to build up its Naval Air Arm and the Arm Air Corps. New models of aircraft of all types were being rushed into production to replace aircraft already known to be obsolescent. The Navy brought aircraft already accepted into full production even as it planned more advanced models. The events in Europe and Asia demonstrated that new fighter designs were needed quickly.
As 1940 dawned the standard fighter aircraft found on U.S. Navy carriers were the F2-A Brewster Buffalo, the Grumman F-3F biplane. In February 1940 the Navy accepted its first F4F-3 Wildcat which in an earlier for had been rejected in favor of the Brewster Buffalo. The new Grumman fighter was powered by a 1200 hp Pratt & Whitney R-1830-76 double row radial engine, mounted 4 .50 cal. Machine guns and was heavily armored. It had a maximum speed of 331 mph range of 845 miles and ceiling of 39500 feet. This would serve it and its pilots well as they aircraft was incredibly tough, often amazing experienced Japanese pilots in their A6M2 Zeros in their ability to suffer heavy damage and remain in the air. The plucky Wildcat would become the main line of defense in the Pacific against the advancing Japanese Imperial Navy in the months following Pearl Harbor.
The early F4F-3s were superseded by the F4F-4 model which incorporated folding wings, additional armor and an extra two machine guns. This decreased its maximum speed to 320 mph, rate of climb and ceiling but nonetheless the aircraft gave a good account of itself in Navy and Marine Corps service. F4F-3's and F4F-4s served in the British Royal Navy where it was called the Martlet until the end of the war. When Grumman closed out F4F production in 1943 to concentrate on its replacement the F6F Hellcat production was continued by General Motors and Eastern Aircraft as the FM1 and FM2 Wildcat. The FM1 was identical to the F4F-4 but armament was reduced to 4 machine guns and bomb racks for two 250 lb bombs or depth charges were added. The FM2 was based on an updated version of the F4F and had a more powerful engine as well as a higher tail assembly to account for the increased torque of the engine. These aircraft served aboard the tiny Escort Carriers and performed valiantly, especially in the Battle off Samar during the Battle of Leyte Gulf. A total of 7860 Wildcats of all varieties were built. They accounted for 1327 enemy aircraft shot down with the loss of only 191 Wildcats.
Aces Capt Joe Foss USMC and CAPT David McConnell USN both Medal of Honor Winners and CDR Jimmy Thatch (below)
The top aces who flew the Wildcat were all Marines, CAPT Joe Foss (26 victories) MAJ John Lucian Smith (19 victories) and MAJ Marion Carl (16 victories in the F4F and 2 in the F4U Corsair). Foss and Smith both won the Medal of Honor. Foss would go on to become Governor of South Dakota and the first Commissioner of the American Football League in 1959. Smith retired as a Colonel in 1960 and Carl as a Major General. Other distinguished F4F aces included LT Butch O'Hare, the first U.S. Navy ace and Medal of Honor winner and LCDR Jimmy Thatch who developed the highly successful "Thatch Weave" which enabled the U.S.pilots whose machines were slower and less maneuverable than the speedy and nimble Zeros to achieve good success against their Japanese foe. Thatch retired as an Admiral in 1967. O'Hare rose to become commander of the Enterprise Air Group and was killed in action in November 1943. Chicago's O'Hare International Airport is named for this brave aviator.
The Grumman F6F Hellcat took over front line fighter duties on the Fleet Carriers from the Wildcat in early 1943 and established itself as the dominant fighter in the Pacific Theater of Operations. Although it had a resemblance to the F4F the F6F was a totally new design built on combat experience against the Japanese. The aircraft was built around the powerful Pratt & Whitney R-2800 engine which produced 2000 hp. The Hellcat mounted six .50 caliber machine guns and had a rate of climb of 3500 feet per minute and a 37300 ft operational ceiling.
Faster than the Zero and other Japanese fighters and piloted by more experienced pilots the Hellcats took a brutal toll of Japanese aircraft. They accounted for more Japanese aircraft kills than any other with 5163 confirmed kills with a loss of 270 aircraft an overall 19:1 kill ratio. They were piloted by 305 Navy and Marine Corps aces including Meal of Honor winner Captain David McConnell the Navy's Ace of Aces, and highest surviving United States ace of the war that scored all 34 of his victories in the Hellcat. The greatest achievement of the Hellcats were when they swept the rebuilt Japanese Naval Air Arm from the skies in the Great Marianas Turkey Shoot. By November 1945 12275 Hellcats had been built with 1263 going to the British Royal Navy. After the war the Hellcat was replaced by the F8F Bearcat as the primary fighter and served in a night fighter and trainer role until the 1950s. The French Navy used the Hellcat in to provide heroic close air support to beleaguered French Soldiers in Indochina.
USMC F4U-4 Corsair providing close air support
Flying alongside the F6F was the Vaught F4U Corsair. The Corsair first flew in 1940 and the Navy was slow to adopt it due to difficulties in carrier operations and negative reviews of Navy pilots. However Marine Corps aviators flying the Corsair had great success and legendary aviators like MAJ Gregory "Pappy" Boyington and VMF-214 the Black Sheep. The Navy would adopt the aircraft later in the war as the Corsair's carrier operation deficiencies were remedied, but its real success was a land based aircraft operated by the Marines. Likewise the first squadrons to operate the aircraft successfully from carriers were the Marine Corps VMF-124 and VMF-213.
Early F4U-1
The Corsair mounted the same Pratt & Whitney R-2800 engine as the F6F but had a highly streamlined gull wing design as well as a turbo-charger which allowed it a top speed of 425 mph. Later models such as the F4U-4 had a top speed of 445 mph. The F4F was armed with six .50 cal machine guns as well as rockets and a bomb load of 2000 pounds and the F4U-4 could carry 4000 pounds of ordnance.
Less than 10000 of the over 64000 combat sorties flown by F4Us were flown from carriers, the vast bulk of the sorties coming from land based Marine Corps squadrons. The Corsair was often used as a fighter bomber where its capabilities to drop sizable amounts of ordinance including rockets, bombs and the nearly developed Napalm in a close air support role cemented the importance of Marine Air for future generations. They were beloved by the Marine Corps and U.S. Army infantrymen in their brutal battles with the Japanese on many hellish island battlefields. Corsairs accounted for 2140 confirmed kills during the war against a combat loss of 189 aircraft. The aircraft remained in production until 1952 with 12571 aircraft of all variants being built. Many Japanese pilots considered the Corsair to be the best fighter of the war.
During the war many Corsairs served in the British Royal Navy and Royal New Zealand Air Force with good success, and after the war the French Navy had success with them in a close air support role in Indochina and Algeria. Following the war the Corsair remained in service for many years in the U.S. Navy and Marine Corps as well as the French Navy and other smaller navies and air forces until the 1960s.
The Douglas SBD Dive Bomber was arguably the most effective Naval dive bomber of World War II, and possibly the best single engine dive bomber of all time. Other aircraft may have been faster or carried a larger bomb load, but the SBD, which served at a time when the U.S. Navy did not have air superiority and battled seasoned Japanese pilots and aircrews, achieved remarkable results,
The SBD was developed from the Northrop BT-2, after Douglas took over Northrop. The first model of the Dauntless, the SBD-1 began operations with the U.S. Marine Corps In 1940, the SBD-2 with the U.S. Navy in 1941. The SBD-3 which included more armor for the crew, and self sealing fuel tanks began entering service in late 1941.
The SBD combined a heavy bomb load, excellent bombing optics, great defensive armament, rugged construction, excellent handling characteristics and maneuverability, and superb dive bombing capabilities. It became the workhorse of the U.S. Navy between 1941 and 1944, flying about 25% of all missions flown from Navy carriers during that time. SBDs sank or damaged six Japanese Aircraft carriers, one Japanese and one French battleship, 14 cruisers, 6 destroyers, and many other ships including transports and submarines. It was the Dauntless which turn the tide of the Pacific war when at Midway they sank the Japanese aircraft carriers Akagi, Kaga, Soryu, and Hiryu and the heavy cruiser Mikuma. The SBD also accounted for more enemy aircraft in aerial combat than were lost to enemy aircraft, an amazing accomplishment by any bomber of any type.
In late 1944 after the Battle Of the Philippine Sea the Dauntless was phased out of U.S. Navy squadrons by the SB2C Helldiver. Though the Helldiver was bigger, faster, and carried a higher bomb load, many pilots preferred the Dauntless due to its superior handling characteristics, especially at low speeds, essential to landing on a carrier. It is hard to believe that the United States would have prevailed in 1942 without the Dauntless.
It was used in combat by other allies, a variant, the A-24 Banshee was built for the U.S. Army Air Force. The French operates it from the carrier Arromanches in Indochina until 1949.
SBD Dauntless Dive Bomber above and at Midway below
TBF Avenger above and below
The TBF Avenger torpedo bomber was developed as a replacement for the TBD Devastator by in 1940 by Leroy Grumman of Grumman aircraft. Production began in 1941 and the first combat by the aircraft was at the Battle of Midway. During that battle, 6 aircraft from VT-6, based at Midway while the rest of the squadron flying TBD Devastators from the USS Hornet attacked the Japanese carrier strike force. All of the TBD were shot down, as well as 5 of the 6 TBFs.
Despite the inauspicious start the TBFs became one of the deadliest aircraft of the Second World War. They helped sink the largest Battleships ever constructed, the Japanese Musashi and Yamato, as well as many other warships and auxiliaries. They conducted bombing missions of land targets, and operated from Escort Carriers in Anti-Submarine Warfare operations and supporting invasions and shore operations. The Avenger was particularly effective in the ASW role and was credited with sinking about 30 German U-Boats and Japanese submarines during the war.
The TBF was the largest single engine aircraft of the war, only the P-47 Thunderbolt was anywhere close to its size. Despite this the TBF was able to operate from the smallest aircraft carriers. Powered by a 1900 HP Wright R-2600-20 Twin Cyclone 14 Cylinder radial engine it could cruise at over 30,000 feet at a top speed of 275 MPH while carrying 2,000 pounds of bombs or a Mark 13 Aerial Torpedo. They also carried racks for 5″ High Velocity Aircraft Rockets and depth charges.
After the war it served in a variety of roles in the U.S. Navy, Royal Navy, Canadian Navy, French Navy, and other militaries until the 1960s. In peacetime it was used for many years as a fire fighting aircraft in the United States and Canada.
LTjg. George H. W. Bush in the cockpit of his Avenger
The most famous man to pilot a TBF/TBM was LTjg George H. W. Bush, later the President of the United States whose aircraft was shot down over Chuchi Jima In 1944.
SB2C Helldiver above and in French Service below
The replacement for the Dauntless was the SB2C Curtiss Helldiver. The Helldiver was bigger and faster than the Dauntless but for its size it was underpowered, and had a shorter range that the beloved Dauntless. The Helldiver had very poor performance in flight, had unreliable electrical and hydraulic systems and frequently was poorly manufactured. The defects made it less than popular among the aircrews which had previously flown the Dauntless who came to call it the Beast. The problems would lead to a Congressional investigation headed by Senator Harry Truman. During the hearings Assistant Secretary of the Navy for Air, Artemis Gates said: "When we needed the SB2C Helldiver neither we nor it was ready."
The British Royal Navy and Australian Air Force evaluated the Helldiver and rejected it for service, cancelling their orders for it.
Despite the many flaws of the aircraft the superbly trained pilots and air crews made the most of it, sinking hundreds of Japanese ships and watercraft. From late 1944 until the end of the war it established a good combat record, though it never had to fight against the well trained Japanese pilots that the Dauntless aircrews had to face.
However, the Navy, and most air forces were moving away from the dive bomber as an attack aircraft. The U. S. Navy found that its F6F Hellcats, and F4U Corsairs could carry as heavy as payload in rockets and bombs as the Helldiver though the ordnance decreased their range. But even so the fighters were far better able to defend themselves against enemy fighter aircraft.
The aircraft served in the U. S. Navy and Naval Reserve until 1950. It also served in Greece where it was used in counter-insurgency (COIN) missions during the Greek Civil War, and by the French Navy during the Indochina campaign, including providing closer air support to French troops at Dien Bien Phu. The Italian Air Force was the last to operate the Helldiver, retiring it in 1959.
With the advent of rockets the dive bomber was replaced by single seat fighters and attack aircraft. The Helldiver was the last purpose built dive bomber. In the U.S. the Hellcat, Corsair, the postwar F8F Bearcat, the P-51 Mustang, and the P-47 Thunderbolt took over ground attack missions. The A4D Skyraider was designed as a ground attack aircraft, and eventually jet powered fighter-bombers would enter service.
These amazing aircraft and the men that flew them established a tradition of excellence that the Naval Aviators of the U.S. Navy and Marine Corps continue today.
Padre Steve
Filed under aircraft, History, Loose thoughts and musings, Military, US Navy, World War II at Sea, world war two in the pacific
Tagged as battle of coral sea, battle of midway, battle of the philippine sea, Curtiss Aircraft, David McConnell, dien bien phu, f4f wildcat, f4u corsair, f6f hellcat, Greek Civil War, Grumman aircraft, harry truman, Joe Foss, John Thatch, Leroy Grumman, Mk 13 Aerial Torpedo, Musashi, naval aviation, naval battle of guadalcanal, sb2c helldiver, SBD Dauntless, TBD Devastator, tbf avenger, US Navy, world war ii, Yamato
The Doomed Fleet: The Ships of the Kido Butai and Their Fates After Pearl Harbor
"We won a great tactical victory at Pearl Harbor and thereby lost the war." Captain Tadaichi Hara
Note: I have written this article as a compliment to The Ships of Pearl Harbor: A Comprehensive List with Short Histories of Each Ship .
Isoruku Yamamoto
The 22 surface warships of Japanese Task Force that struck Pearl Harbor on December 7th 1941 turned west after the last aircraft were recovered. No ships were lost or damaged in the attack. Only 29 aircraft and 55 aircrew were lost. Additionally 5 midget submarines and their 10 crew members were lost, one became the first Japanese Prisoner of War when his sub beached off Diamond Head.
Though the Japanese had heavily damaged the Pacific Fleet, sinking or damaging all 8 battleships that were in port at Pearl Harbor on December 7th the victory was incomplete. Pearl Harbor's fleet support facilities, dry docks and fuel tank farms remained allowing the fleet to maintain it as a base. Likewise no carriers were in port and they as well as the submarine force were soon in action against the now vastly superior Imperial Navy which after Pearl Harbor wreaked havoc on US, British, Dutch and Australian forces in the Western Pacific and Indian Ocean.
Kirishima and Akagi
Little did the heady Japanese expect that in less than six months that four of the six carriers that carried out the attack would be at the bottom of the Pacific and another heavily damaged. That was only the beginning. When the Japanese forces encountered the American carriers at Coral Sea and Midway the tide turned in the Pacific. Yamamoto's remarks to Matsumoto and Konoe were more prophetic than even he might have imagined. Less than 18 months later Yamamoto himself would be dead, killed when a Betty bomber carrying him was ambushed and shot down near Buin New Guinea.
Of the 22 surface ships involved in the attack only one, the Fubuki Class Destroyer Ushio survived the war. What follows is what happened to the other ships in the order of their loss.
The aircraft carrier Kaga was designed as a battleship but converted to an aircraft carrier during construction as part of the 1922 Washington Naval Treaty. She was active throughout the 1930s in the war against China and participated in every major action of the 1st Air Fleet until she was sunk at Midway on June 4th 1942. Hit by at least 4 bombs by dive bombers from the USS Enterprise while her flight deck was crowded with fueled and armed aircraft and decks strewn with bombs and torpedoes that in the rush of battle had not been returned to her magazines. That evening with the fires still burning her survivors were taken off and she was scuttled by torpedoes fired by destroyer Hagikaze. Over 800 of her crew of over 1700 including her Captain and most senior officers were lost.
Soryu
The Aircraft carrier Soryu at 18,800 tons was roughly the same size as the American Yorktown Class. She was commissioned in 1937 and after Pearl Harbor fought as a unit of the First Air Fleet. She was present at Midway and sunk by dive bombers from the USS Yorktown. Hit by 3 bombs she was ordered abandoned within 15 minutes and sunk on the evening of June 4th taking down 711 of over 1100 crew members.
Akagi
The aircraft carrier Akagi was the Flagship Vice Admiral Nagumo of the 1st Air Fleet at Pearl Harbor and during the operations against Allied forces in the Western Pacific. She retained that role at Midway when on the morning of June 4th 1942 she was hit by a 1000 pound bomb from one of three attacking aircraft from Scouting Six from the Enterprise. With her aircraft on deck fully armed and fueled for a strike against the American carriers she was highly vulnerable. The explosion triggered a chain reaction as fuel and ordnance turned the great ship into a blazing inferno. Admiral Nagumo transferred his flag to the light cruiser Nagara. Damage control teams fought a losing battle against the conflagration but the next morning Admiral Yamamoto ordered his former ship scuttled. 267 Japanese sailors died on Akagi.
Hiryu damaged at Midway
The carrier Hiryu, a close sister of Soryu also participated in the success of the First Air Fleet up to Midway. As flagship of of Carrier Division 2 avoided damage in the initial strike. Her aircraft heavily damaged Yorktown but she suffered the same fate as the other carriers that evening. Hit by four 1000 pound bombs from dive bombers from Enterprise she burned throughout the night and was scuttled on June 5th with the loss of 389 sailors and aviators.
Asashio Class
The 2000 ton Asashio class destroyer Arare was torpedoed and sunk by the submarine USS Growler on July 5th 1942 off Kiska Harbor Alaska with the loss of 104 of her crew. At the time of her loss she was escorting seaplane tender Chiyoda on a supply mission.
Hiei
The Kongo Class battleship Hiei was sunk during the first Naval Battle of Guadalcanal. She was the first Japanese battleship sunk during the war. Heavily damaged during a close quarters surface engagement she was sunk by aircraft from Enterprise off Savo Island on November 13th 1942. 188 of her crew were lost with the ship.
Kirishima
The Battleship Kirishima, a sister ship of Hiei was present with Hiei in the First Naval Battle of Guadalcanal. She survived that fight and was attached to another surface raiding group. The next night while engaging the USS South Dakota, Kirishima was targeted by the Battleship USS Washington and sunk by gunfire. 212 crewmen went down with the battleship.
The destroyer Kagero, the lead ship of her class was among the most deadly destroyer types produced in the war. Armed with six 5" guns and 8 24" Long Lance Torpedo tubes she and her sisters wrought fearful damage on allied surface forces in many of the vicious battles in the South Pacific. During a supply run Kagero stuck a mine and was disabled. Unable to maneuver she was sunk by US aircraft on May 7th 1943 off Rendova with the loss of 18 sailors.
The Kagero's sisters also suffered. Akigumo was torpedoes and sunk by the submarine USS Redfin on April 11th 1944 off Zamboanga the Philippines. Tanikaze was torpedoed and sunk by USS Harder on June 9th 1944 with the loss of 114 sailors.
Shokaku
The 27,000 ton carrier Shokaku was one of the newest and most modern carriers in the fleet at Pearl Harbor. She was heavily damaged at Coral Sea and missed the Midway operation. At the Battle of Eastern Solomons her aircraft damaged the Enterprise. At the Battle of Santa Cruz she was again damaged but her aircraft mortally wounded the USS Hornet which was sunk by destroyers. She was part of a reconstituted carrier strike force at the Battle of the Philippine Sea. While sailing to the battle she was struck by 3 torpedoes from the USS Cavalla on June 19th 1944 with the loss of 1272 of over 1800 souls on board.
Zuikaku's crew saluting the colors before abandoning ship
The Battle of Leyte Gulf accounted for many of the surviving ships of the Kido Butai. Carrier Zuikaku, sister of Shokaku had fought at Coral Sea, as well as Eastern Solomons and Santa Cruz. She was damaged and lost most of her air group at Philippine Sea. Repaired she was assigned to Admiral Ozawa's decoy group of four carriers with very few aircraft at Leyte Gulf. Hit by seven torpedoes and nine bombs the gallant ship sunk with the loss of 842 of her crew of over 1700.
Chikuma
The Heavy Cruiser Chikuma was served mostly as an escort to the carrier forces and was at Midway as well as Eastern Solomons and Santa Cruz. On October 25th at Leyte Gulf she succumbed to multiple bomb and torpedo hits delivered by US carrier aircraft in the Battle off Samar. Nearly all of her survivors rescued by destroyer Nowaki were lost when that ship was sunk the next day.
The elderly Nagara Class light cruiser Abukuma was torpedoed and heavily damaged by a torpedo fired by the US PT-137 at the Battle of Surigao Strait and disabled. She was bombed and sunk by US Army Air Force Aircraft off Negros on October 26th with the loss of 250 sailors.
The Kagero Class destroyer Shiranui had a long and distinguished career and survived a torpedo hit from USS Growler in July 1942 which blew off her bow. She was bombed sunk with the loss of all hands on October 27th 1944 after surviving the Battle of Surigao Strait.
The Fubuki Class destroyer Akebono was sunk at pier side at Cavite Naval Yard, Manila Bay by US Army Air Corps bombers on November 27th 1944.
Hamakaze 1941 and Isokaze below
Three of the survivors were sunk during the last offensive sortie of Japanese warships. On April 7th the Kagero Class Isokaze and Hamikaze and Asashio Class Kasumi were sunk by US carrier aircraft while escorting the battleship Yamato on her suicide mission at Okinawa.
Wreck of Tone at Kure
The Heavy Cruiser Tone, sister of Chikuma survived many battles and was sunk at anchor in Kure harbor by US carrier aircraft on July 24th 1945. Her hulk was scrapped between 1947 and 1948.
Ushio after the war
Only Fubuki Class destroyer Ushio survived the war. A survivor of many battles she helped sink the submarine USS Perch in 1942. Surrendered to the US Navy she was scrapped in 1948.
Admiral Yamamoto was right when he told cabinet minister Shigeharu Matsumo to and Japanese prime minister Fumimaro Konoe "In the first six to twelve months of a war with the United States and Great Britain I will run wild and win victory upon victory. But then, if the war continues after that, I have no expectation of success."
Filed under History, Military, Navy Ships, world war two in the pacific
Tagged as admiral chuichi nagumo, asashio class, battle of coral sea, battle of eastern solomons, battle of leyte gulf, battle of midway, battle of santa cruz, battle of the philippine sea, cavite naval yard, first air fleet, fubuki class, fumimaro konoe, ijn abukuma, ijn akagi, ijn akebono, ijn akigumo, ijn arare, ijn chikuma, ijn hagikaze, ijn hamakaze, ijn hiei, ijn hiryu, ijn isokaze, ijn kaga, ijn kagero, ijn kasumi, ijn kirishima, ijn nagara, ijn nowaki, ijn shiranui, ijn shokaku, ijn soryu, ijn tanikaze, ijn tone, ijn ushio, ijn yamato, ijn zuikaku, Isoruku Yamamoto, kagero class, okinawa, pearl harbor attack, pt-137, Shigeharu Matsumo, tadaichi hara, uss cavalla, uss enterprise cv-6, uss growler, uss harder, uss hornet cv-8, uss perch, uss redfin, uss south dakota bb-58, uss washington bb-56, uss yorktown cv-5
The South Dakota Class Battleships: The Best of the Treaty Battleships
USS South Dakota Class Line Drawing
This is the fifth in a series of six articles on the battleships built under the provision of the Washington and London Naval Treaty limitations in the 1930s. I am not including the ships which were completed in the immediate aftermath of the Washington Treaty limitations. This series looks at the modern battleships that the World War II combatants would produce in the 1930s which saw service in the war. Part one covered the Italian Vittorio Veneto class entitled The Pride of the Regina Marina: The Vittorio Veneto Class Battleships. Part two French Firepower Forward: The unrealized potential of the Dunkerque and Richelieu Class Battleships covered the French Dunkerque class and Richelieu class Battleships. Part three covered the British Royal Navy King George V Classbattleships entitled British Bulwarks: The King George V Class Battleships Part Four which was about the North Carolina Class is entitled The Next Generation: The North Carolina Class Battleships. I have already published the final part which covers the German Scharnhorst Class entitled Power and Beauty the Battle Cruisers Scharnhorst and Gneisenau . The German Bismarck, Japanese Yamato, British Vanguard and American Iowa
Classes will be covered in a subsequent series.
As the world edged closer to war in the late 1930s the U.S. Navy followed up its decision to build the two ship North Carolina class battleships with additional fast battleships. Initially the General Board wanted two additional North Carolina's but the Chief of Naval Operations William H. Standley wanted a different design.
In order to accommodate the machinery necessary to provide the desired speed of 27 knots on the shorter hull the machinery spaces were rearranged. The new design placed the boilers directly alongside the turbines with the ship's auxiliaries and evaporators also placed in the machinery rooms. Additional design changes made to save space included making the crew berthing areas smaller. This included that of officers as well as the senior officers and shrinking the size of the galley's and the wardroom from those on the North Carolina's. The resultant changes allowed the ships to achieve the 27 knot speed, improved protection and the same armament of the North Carolina's within the 35,000 treaty limit.
The lead ship of the class the USS South Dakota BB-57 was laid down 5 July 1939 at New York Shipbuilding in Camden New Jersey, launched on 7 June 1941 and commissioned on 20 March 1942. Following her commissioning and her shakedown cruise South Dakota was dispatched to the South Pacific. Soon after her arrival she struck a coral reef at Tonga which necessitated a return to Pearl Harbor for repairs. When repairs were complete she was attached to TF 16 escorting the USS Enterprise CV-6 during the Battle of the Santa Cruz Islands on 26 October 1942. During the battle she was credited with shooting down 26 Japanese aircraft but was struck by a 500 lb bomb on her number one turret. She joined TF-64 paired with the battleship USS Washington during the Second Naval Battle of Guadalcanal on14-15 November 1942. During the action South Dakota suffered a power outage and was hit by over 40 shells from Japanese ships which knocked out 3 fire control radars, her radio and main radar set. 3 destroyers were also lost but the Washington mortally wounded the fast battleship Kirishima and destroyer Ayanami which were scuttled the next day and damaged the heavy cruisers Atago and Takao. She returned to New York for repairs which completed in February 1943 and joined the carrier USS Ranger CV-4 for operations in the Atlantic until April when she was attached to the British Home Fleet. She sailed for the Pacific in August 1943 and rejoined the Pacific Fleet in September and joined Battleship Divisions 8 and 9 and supported the invasion of Tarawa providing naval gunfire support to the Marines. The rest of the war was spent escorting carriers as well as conducting bombardment against Japanese shore installations. She was present at the Japanese surrender in Tokyo Bay and returned to the United States in 1945 and was decommissioned and placed in reserve on 31 January 1947. She was stricken from the Naval Register on 1 June 1962 and sold for scrap in October of that year. Various artifacts of this gallant ship to include a propeller, a 16" gun and the mainmast are part of the USS South Dakota Memorial Park in Sioux Falls South Dakota and 6,000 tons of armored plate were returned to the U.S. Atomic Energy Commission for use in civilian nuclear programs and a second screw is displaced outside the U.S. Naval Museum in Washington D.C. She received 13 battle stars for World War II service. South Dakota had the dubious distinction of having the youngest sailor of the war 12 year old Calvin Graham who confessed lying about his age to the Gunnery Officer Sergeant Schriver. Graham was court-martialed and given a dishonorable discharge spending 3 months in the ship's brig before he was able to be returned to the United States where just after his 13th birthday he entered 7th grade.
The second ship of the class the USS Indiana BB-58 was laid down at Newport News Naval Shipyard on 20 November 1939 launched on 21 November 1941 and commissioned on 30 April 1942. She served throughout the Pacific War by serving with the fast battleships of Vice Admiral Willis Lee's TF-34, escorting carriers during major battles such that the Battle of the Philippine Sea or as it is better known the Marianas Turkey Shoot. She returned to the United States for overhaul and missed the Battle of Leyte Gulf but served at Iwo Jima, Okinawa and operations against the Japanese home islands. Following the war she was decommissioned in 1947 and sold for scrap in September 1963. A number of her relics are preserved at various locations in Indiana and her prow is located in Berkeley California.
The third ship of the class the USS Massachusetts BB-59 was laid down on 20 July 1939 at Bethlehem Steel Corporation Fore River Yard in Salem Massachusetts and launched on 23 September 1941 and commissioned on 12 May 1942. After her shakedown cruise she was assigned to the Atlantic Fleet where she took part in Operation Torch, the Allied invasion of French North Africa. During the operation she engaged French shore batteries, damaged the battleship Jean Bart and sank 2 cargo ships and along with the heavy cruiser Tuscaloosa sank the destroyers Fougueux and Boulonnais and the light cruiser Primauguet. Following her assignment in the Atlantic she sailed for the Pacific where she began operations in January 1944. She took part in almost every major operation conducted by the Pacific Fleet escorting the Fast Carrier Task Forces and operating as a unit of TF-34 the Fast Battleship Task force including the Battle of Leyte Gulf. She ended the war conducting operations against the Japanese home islands. She was decommissioned in 1947 and stricken from the Naval Register on 1 June 1962. She was saved from the fate of Indiana and South Dakota as the people of Massachusetts with the assistance of schoolchildren who donated $50,000 for her renovation and preservation as a memorial. She became that in 1965 at Battleship Cove in Fall River Massachusetts and she remains there designated as a National Historic Landmark. During the naval build up of the 1980s much equipment common to all modern battleships was removed for use in the recommissioned battleships of the Iowa class.
USS South Dakota at the Battle of the Santa Cruz Islands
The final ship of the class the USS Alabama BB-60 was on 1 February 1940 at Norfolk Naval Shipyard. She was launched on 21 February 1942 and commissioned 16 August 1942. Following her shakedown cruise and initial training off the Atlantic coast she joined the repaired South Dakota and operated as part of TF 22 attached to the British Home Fleet. She conducted convoy escort operations, participated in the reinforcement of Spitsbergen and in an operation which attempted to coax the German battleship Tirpitz out of her haven in Norway. Tirpitz did not take the bait and Alabama and South Dakota returned to the United States in August 1943. After training with the fast carriers she took part in the invasion of the Gilberts taking part in Operation Galvanic against Tarawa and the Army landings on Makin Island. As 1944 began Alabama continued her operations with the fast carriers and the fast battleships of TF-34. She took part in operations against the Marshalls and took part in the invasion of the Marianas Islands and the Marianas Turkey Shoot. From there she supported the invasion of Palau and other islands in the Caroline Islands followed by operations against New Guinea and the invasion of the Philippine and the Battle of Leyte Gulf before returning to the United States for overhaul. She returned to action during the invasion of Okinawa and in shore bombardment operations against the Japanese Mainland. When the war ended the Alabama had suffered no combat deaths and only 5 wounded following the misfire of one of her own 5" guns earning her the nickname of "Lucky A." Hall of Fame pitcher Bob Feller served as a Chief Petty Officer and gun mount captain on Alabama during the war. She was decommissioned on 9 January 1947 and stricken from the Naval Register on 1 June 1962. The people of the State of Alabama formed the "Alabama Battleship Commission" and raised $1,000,000 including over $100,000 by schoolchildren to bring her to Alabama as a memorial. She was turned over to the state in 1964 and opened as a museum on 9 January 1965. She was declared a National Historic Landmark in 1986. She has been used as a set in several movies and continues to serve as a museum preserving the legacy of the men that served aboard her and all of the battleship sailors of World War II.
In the 1950s a number of proposals were considered to modernize the ships of the class to increase their speed to 31 knots using improved steam turbines or gas turbines. The Navy determined that to do this would require changes to the hull form of the ships making the cost too prohibitive. The ships were certainly the best of the treaty type battleships produced by any nation in the Second World War. The damage sustained by South Dakota at the Second Naval Battle of Guadalcanal would have not only put most battleships of her era out of action but might have caused enough damage to sink them. Their armament was equal or superior to all that except the Japanese Yamato Class and their protection was superior to most ships of their era.
It is good that both the Massachusetts and the Alabama have been preserved as memorials to the ships of the class, their sailors and the United States Navy in the Second World War. Because of the efforts of the people of Massachusetts and Alabama millions of people have been able to see these magnificent ships and remember their fine crews. Both have hosted reunions of their ships companies since becoming museum ships and with the World War Two generation passing away in greater numbers every day soon these ships as well as the USS Texas, USS North Carolina, USS Missouri, USS New Jersey and USS Wisconsin will be all that is left to remember them unless a home can be found for the USS Iowa which stricken from the Naval Register awaits an uncertain fate as a resident of the "Ghost Fleet" in Suisun Bay California. No other nation preserved any other dreadnought or treaty battleship thus only these ships remain from the era of the Dreadnought.
Filed under History, Military, Navy Ships, US Navy, world war two in europe, world war two in the pacific
Tagged as 5" 38 guns, admiral william h standley, alabama battleship commission, battle of santa cruz, battle of the philippine sea, battleship armament, battleship armor protection, battleship cove fall river massachusetts, bethlehem steel corporation, boulonnais, british home fleet, dreadnought era, fore river shipyard, fougueux, ijn atago, ijn ayanami, ijn kirishima, ijn takao, iowa class, jean bart, london naval treaty, makin island, marianas turkey shoot, marshall islands, national historic landmarks, new york shipbuilding camden nj, newport news naval shipyard, norfolk naval shipyard, north carolina class, operation galvanic, operation torch, preservation of uss massachusetts as memorial, primauguet, seaman calvin graham, second naval battle of guadalcanal, sergent shriver, south dakota class, tarawa, tf-16, tf-34, tf-38, tf-58, tirpitz, treaty battleships, uss alabama, uss enterprise cv-6, uss indiana, uss massachusetts, uss north carolina, uss ranger cv-4, uss south dakota, uss south dakota memorial park, USS Texas, uss tuscaloosa, uss washington, vice admiral willis lee, washington naval treaty, yamato class


text:
Cheap speaker deals to check out october 2021
High-quality speakers aren't usually sold out, but on rare occasions you can find a solid, high-quality speaker deal that you shouldn't miss. We've done the hard work for you by finding the best cheap speaker deals and sales for quality speakers.
Our speaker deals include top brands like Sony, LG, and Yamaha. If you're concerned about price as far as quality goes, we've found that some of the cheapest soundbars on the market can still add a decent level of clarity and sound appeal to your living room on a scale your average TV can't.
In general, speaker deals tend to be best around big shopping events like Black Friday or Amazon Prime Day, which usually take place in November and July, respectively. However, good deals pop up all year round, so if you miss a retail event, this isn't a big deal.
Once you get your hands on the new soundbar, the results speak for themselves. But trying to research and find the best soundbar deal right now can be a drawn out effort. That's because the world of speakers and audio products in general is filled with a random string of numbers — the Vizio SB-3830-D0 38-Inch Soundbar, anyone?
There are also plenty of drastic price differences that can be overwhelming for even the most seasoned audiophile. But don't worry, this is where we come in.
What is the best Soundbar deal?
As you would expect, the answer to this question will be different from person to person.
Some people are fine with a standard soundbar, meaning no subwoofer and no streaming capabilities. Others may want the sub, but there is no flow. Then there are those who might want all of the above, plus satellite speakers. It is a case that may vary by miles.
However, we can give you some good ideas of what to look for and where to find those great deals as they pop up.
For most people, you really only want the most basic package: a soundbar with a digital audio cable input that should plug into most modern TVs. You can be a little finicky with the HDMI lanes, RCA inputs, and 3.5mm jacks, but sometimes basic is best. Of course, we also recommend looking for speakers with a subwoofer included, that way you'll get the full sonic range from your favorite TV shows and movies, not just the highs and mids.
There are tons of speakers to choose from, and more come out every week, so without further ado, here are the best cheap speaker deals we found this month.
Best cheap speaker deals
(Image credit: Amazon)
Yamaha Soundbar SR-B20A
Immersive sound in a modest package
Dimensions: 5.2 x 7 x 38 inches | Weight: 7.1 lbs | Energy: 120 watts | Links: 1 HDMI (ARC) Output, 2 Digital Optical Inputs, Bluetooth
Today's best Yamaha SR-B20A deals
DTS Virtual: X 3D sound
Detailed midrange
Compact and beautifully finished
Single-note bass response
It cost more than its predecessor
The Yamaha SR-B20A amplifier was released in 2020 to replace the popular YAS-107 from 2017. It may be a bit more expensive than its predecessor, but the Yamaha SR-B20A is made just enough to justify the increase. Within the compact form factor are a pair of 75mm bass drivers, two 55mm mid-range drivers located at either end of the woofer, and two 25mm tweeters facing down.
Most notably, the Yamaha SR-B20A boasts a very detailed mid-range—excellent news if you're into a lot of dialogue-heavy movies. Obviously, you won't benefit from the Dolby Atmos sound found in more expensive soundbars, but the SR-B20A delivers DTS Virtual:X 3D for impressive 3D surround sound in its own right.
If you just want to boost your TV's original sound, the Yamaha SR-B20A soundbar is an affordable way to do it.
Read the review: Yamaha Soundbar SR-B20A (Opens in a new tab)
(Image credit: Roku)
Roku streambar
Half volume speaker, full volume sound
Dimensions: 2.4 x 4.2 x 14 inches | Weight: 2.4 lbs | Energy: not available | Links: 1 HDMI (ARC) Input, 1 Optical Input, 1 USB, Bluetooth, Wi-Fi
new, renovated
Today's best Roku Streambar deals
Built-in 4K media streaming
Bluetooth and Wi-Fi
Very good sound for its size
Weak bass
Adding ingredients gets expensive
The Roku Streambar is one step closer to giving your TV a new look. It will not only make your TV sound fuller and cleaner – it will also give it a 4K / HDR stream. It's only 14 inches wide, which makes the Roku Streambar a great choice for anyone who lives in an apartment or dorm room.
Wireless connectivity options include Bluetooth and Wi-Fi. Hard-wired Ethernet is also possible through the single USB port. Sonically, the Roku Streambar is very good, providing clear dialogue and voice leveling for commercials. The bass is lacking, but you can remedy this issue by purchasing the Roku subwoofer and rear speaker sets (sold separately).
If you need a soundbar and streaming device—but have limited space and a budget—the Roku Streambar is the way to go.
Read the review: Roku streambar (Opens in a new tab)
Sony HT-G700 Soundbar
The perfect complement to Sony TVs in particular
Dimensions: 2.5 x 4.3 x 38.9 inches (bar). 7.6 x 15.2 x 16 inches (sub) | Weight: 7.7 lbs (bar). | 16.5 lbs (sub) | Energy: 400 watts | Delivery: 1 HDMI input, 1 HDMI (ARC) output, Bluetooth
Today's best Sony HT-G700 deals
Atmos, DTS:X, and immersive AE
Custom sub volume
Best for movies and TV
Not ideal for music
Exaggerated height/circumference claims
The Sony HT-G700 3.1-channel soundbar delivers excellent TV and movie sound. Although it will significantly boost the sound on any TV, certain features (such as stereo Bluetooth) will only work with a number of compatible Sony TVs. Thus, if you're already invested in Sony's home theater ecosystem, you'll be able to harness the full potential of the HT-G700.
The Sony HT-G700 is a pair of speakers and a wireless subwoofer featuring Dolby Atmos, DTS:X, and Sony's Immersive AE. This wide range of audio formats translates into clear, spacious sound while watching your favorite TV shows and movies. And if you want to customize your sub frequencies on the go, there's a dedicated subwoofer button to get the bass right where you need it.
For a powerful entry-level Atmos-enabled speaker/subwoofer combo, definitely consider the Sony HT-G700.
Read the review: Sony HT-G700 (Opens in a new tab)
Sony HT-X8500 Soundbar
High performance at an affordable price
Dimensions: 35.1 x 3.9 x 2.6 inches | Weight: 1 lb. | Energy: not available | Links: 1 HDMI In, 1 HDMI Out (ARC), Analog Audio In/Out, Ethernet, Optical Audio In, Bluetooth, Wi-Fi
Slim and elegant design
Built-in dual subwoofer
3D surround sound
No recall drivers
There is no high-resolution audio
The Sony HT-X8500 delivers high quality sound at an affordable price. It includes a built-in dual subwoofer for deep bass, while maintaining a slim and elegant design. Its compact size fits perfectly on your TV and won't clutter up your space.
This Sony soundbar features Vertical Sound Engine technology that is combined with Dolby Atmos and DTS:X to produce a cinematic 3D surround sound experience. The remote also includes seven different sound modes so you can control and enhance your entertainment experience.
If you're looking for a first-class sound system that won't make a huge dent in your budget, the Sony HT-X8500 is one of the best options out there.
Read the review: Sony HT-X8500
Razer Leviathan
Designed for gamers, but great for home entertainment, too
Dimensions: 2.9 x 3.1 x 19.7 inches | Weight: 10 lbs | Energy: 30 watts | Links: Bluetooth, 1 optical audio input, 3.5mm audio port
Today's best Razer Leviathan deals
Heavy bass
Lots of input
Limited surround sound
Unstable subconductor
The Razer Leviathan may be an older, gaming-oriented model, but it's actually a really smart soundbar that costs less than most TVs — and it'll help those TVs look a lot better, too.
Razer's beast of sound doesn't have the most power per inch at just 30W, but we really liked how low it goes with the accompanying subwoofer. Plus, while the other speakers on this list might not even attempt surround sound, Razer gives it an ol' total experience and really does a decent job with it.
The Razer Leviathan may not be as good as a true 7.1 system, but try to find one of these for less than $199 / £159. You are getting a great deal here.
Read the review: Razer Leviathan
LG SK8Y Soundbar (U.S. only)
Powerful sound and attractive design
Dimensions: 2.4 x 3.5 x 41.7 in. (bar). 8.7 x 15.4 x 12.3 inches (sub) | Weight: 6.6 lbs (bar) | 16.8 lbs (sub) | Energy: 360 watts | Delivery: One HDMI input, one HDMI output, optical audio output, Bluetooth, Wi-Fi
Today's best LG SK8Y deals
Lots of source options
Open and clear sound
Stylish and compact shape
The sub sounds are flat
Atmos' claims are questionable
The LG SK8Y may not be the newest model on the market, but it's still a great value soundbar. The speaker has one of the most attractive designs we've seen; It can fit neatly on the bottom of the TV. Meanwhile, the accompanying sub has a sharper front and can go right behind the sofa or under a sideboard.
The LG SK8Y's sound quality and source flexibility are worth what you pay for here, and then some. In addition to Bluetooth and Wi-Fi, there is also support for Chromecast as well as Google Assistant control. And the display on the speakers isn't too shabby either.
Unfortunately, this model is no longer available in the UK. However, if you're in the US, pick up the well-priced LG SK8Y while you can.
Read the review: LG SK8 (LG SK8Y) (Opens in a new tab)
More articles about home audio:
Collection of today's best deals
Best cheap RAM deals and prices for gaming, desktop and laptops
Apple HomePod 2: Everything you need to know

redpajama_set_name: RedPajamaCommonCrawl


text:
Home > MLB Picks and News > Cincinnati Reds Introduce Contactless Payment For Home Games
MLB Picks and News	 June 15, 2021
With professional sports teams starting to reopen their games to fan attendance as the COVID-19 vaccination effort expands a priority is being made on doing it safely. Most teams are allowing only a limited percentage of capacity to be ticketed and require other mitigation steps such as masks and social distancing.
There are a number of teams that clearly expect a greater expectation for cleanliness among fans to continue for the foreseeable future. To satisfy this concern, there is a move toward eliminating cash at concession stands and other point of sale terminals. The latest to get on the contactless payment bandwagon is the Cincinnati Reds who are partnering with Tappit, a company that has found a market niche in helping teams implement these technologies.
The system at Cincinnati's Great American Ball Park will be called 'Reds Pay'–a mobile payment solution that is integrated into the team's official app. This will allow fans to make purchases using only a cellphone linked to a bank or credit card. This should not only speed up the process of buying food, drinks and merch but will do so while minimizing the potential for transmission of germs and viruses.
It also provides marketing opportunities for the team. The Reds can send personalized vouchers, marketing offers, etc. directly to fans mobile app. The data they receive in return is also put to work to help the team maximize the fan experience and improve their in-stadium operations.
Phil Castellini, Reds President and Chief Operating Officer, likes the benefits provided by the Tappit technology:
"Health and safety are at the forefront of all our fan experience upgrades. The Tappit technology that powers the new Reds Pay platform helps minimize contact, speed up transactions and expands our customer service capabilities."
Tappit's CEO, Jason Thomas details the many ways that his company's technology can help a team like the Reds:
"At Tappit, our priority is to ensure that fans have a great experience as they're returning to live events. It's important for venues to take as many safety measures as possible to reassure fans and staff alike. Not only is Tappit providing a cleaner, more seamless payment experience, but we are also equipping teams like the Cincinnati Reds with invaluable customer insights and data other payment methods can't provide. As a result, teams will learn to better understand their fans and be able to provide them with a truly personalized fan experience whilst boosting profits."
Don't be surprised if every pro sports team introduces contactless payments at their home venue in the next couple of years.


Burnout Revenge Free Download Full Version PC Game Setup In Single Direct Link For Windows. It Is A Best Action Base Racing Game.
The fourth Burnout racing game puts you once again in the eye of traffic storms. Where you do not only rush to be the fastest, but brutally, yet stylishly, take down your opponents. This is emphasize by impact time, which shows crashes in all their slowed-down glory. And the boost you receive after a successful wrecking. Reckless driving bumps your Revenge rank, unlocking new events. Non-racing vehicles are no longer a nuisance with the sole purpose of slowing you down. They can now be actively use to obstruct traffic or send them into your foes. This can also be achieve by medal placings that grant new vehicles.
Before You Start Burnout Revenge Free Download. Make Sure Your PC Meets Minimum System Requirements.
Click On The Below Button To Start Burnout Revenge Free Download. It Is Full And Complete Game. Just Download And Start Playing It. We Have Provided Direct Link Full Setup Of The Game.


text:
\section{Introduction} \label{intro}
Recently, many car-following models have been developed for jam avoidance in highways.
Models have equilibrium homogeneous solutions where all vehicle speeds and spacings are constant and equal.
`Jam avoidance property' is investigated through analysis of the stability of such solutions.
Most of the approaches are extended versions of the \textit{optimal velocity} (OV) model \cite{ovm}.
The basic model is solely based on the distance spacing with the predecessor (local next-neighbour interaction).
Several studies shown that speed and spacing feedback mechanisms in autonomous OV models allow to improve the stability of the homogeneous solution
and to avoid jam formation \cite{Konishi1999,Konishi2000,Davis2004,Zhao2005,Jin2013}.
Similar results are obtained with the \textit{intelligent driver} (ID) model for specific parameter values \cite{Kesting2007,Kesting2008}.

Several vehicles in the neighbourhood are taken in the interaction for collective (or cooperative) systems.
Many studies show improvements of the stability if the number of predecessors in interaction increases \cite{Lenz1999,Hasebe2003,Wilson2004,Hu2014}.
Comparable results are obtained with symmetric interaction
(interaction with predecessors and followers, see for instance \cite{Nakayama2001,Monteil2014}).
Oppositely to autonomous models for which the variables can be directly measured, cooperative systems require that the vehicles are connected to communicate their states.
This makes difficult their implementation.

In this paper, autonomous linear OV models and extended ones with speed difference term are compared to their collective versions
including several predecessors in interaction.
Both extended and collective OV models describe significant improvement of the stability.
More precisely, we observe that the number of predecessors in interaction in the collective models and
the speed difference term in the autonomous approaches have similar roles in the dynamics.
The paper is organized as follow.
The linear jam avoidance models are introduced in section~\ref{def}.
The results of simulation experiment of a jam are presented in section~\ref{sim},
while the Lyapunov exponents of the different autonomous and collective models are calculated in section~\ref{exp}.
The section~\ref{ccl} gives conclusion and outlook.

\section{Linear jam avoidance models}\label{def}

The optimal velocity model is
\begin{equation}\textstyle
\ddot x_n(t)=\frac1T\big(V(\Delta x_n(t))-\dot x_n(t)\big),
\label{ovm}
\end{equation}
with $x_n(t)$ the position of the vehicle $n$ at time $t$,
$\Delta x(t)=x_{n+1}(t)-x_n(t)$ the distance spacing with
$x_{n+1}>x_n$ the predecessor position (see figure~\ref{scheme}), and $T>0$ the relaxation (or reaction) time  \cite{ovm}.
A jam avoidance should have stable homogeneous solution.
More precisely it should be locally stable with no oscillation (LSNO) to avoid collision and globally stable (GS),
see for instance \cite[Chapter 15]{bookTreiber}.
The conditions ensure a collision-free convergence of the system to the homogeneous solution for any initial condition.
With OV model the OV model, the linear LSNO and GS conditions are respectively~:
\begin{equation}\textstyle
V'<\frac1{4T}\qquad\mbox{and}\qquad V'<\frac1{2T}.
\end{equation}
Note that the first condition implies the second.
The \textit{full velocity difference} (FVD) is an extended OV model including speed difference term \cite{Jiang2001}~:
\begin{equation}\textstyle
\ddot x_n(t)=\frac1{T_1}\big(V(\Delta x_n(t))-\dot x_n(t)\big)+\frac1{T_2}\Delta \dot x_{n}(t).
\label{fvdm}
\end{equation}
It includes two relaxation times $T_1>0$ and $T_2>0$.
The model is the same as the OV model at the limit $T_2\rightarrow\infty$.
For the FVD model, the LSNO and GS conditions are respectively~:
\begin{equation}\textstyle
V'<\frac1{4T_1}\left(1+\frac{T_1}{T_2}\right)^2 \qquad\mbox{and}\qquad V'<\frac1{2T_1}+\frac1{T_2}.
\end{equation}
These conditions are simply $V'<1/T$ if $T_1=T_2=T$ (the first inequality implies the second if $T_1<3T_2$).
Clearly, the speed difference has a stabilization effect on the dynamics.
The LSNO and GS conditions always hold at the limit $T_2\rightarrow 0$.

\begin{figure}[!ht]\begin{center}%
\vspace{-25mm}\includegraphics{scheme.pdf}\vspace{-22.5mm}
\caption{Notations used. $x_n$ is the position and $\Delta x_n$ is the spacing of the vehicle $n$.}
\label{scheme}
\end{center}\end{figure}

The models (\ref{ovm}) and (\ref{fvdm}) are autonomous ones~:
they are solely based on distance spacing and speed difference with the predecessor.
Collective models depend on several predecessors in front.
Generally,  collective OV models have the form $\ddot x_n(t)=\sum_{k=1}^K F_k\big(\Delta x_{n,k}(t),\dot x_n(t),\Delta \dot x_{n+k}(t)$,
where $K$ is the number of predecessors taking into account and $\Delta x_{n,k}=x_{n+k}-x_k$ is the distance to the vehicle $n+k$.
$F_k$ represents the influence of the vehicle $k$ on the acceleration rate of the considered vehicle.
In the \textit{Multi-anticipative} (MA) model \cite{Lenz1999}, this influence is
\begin{equation}\textstyle
F_k =\frac{\alpha _k}T\big(V\left(\Delta x_{n,k}(t)/k\right)-\dot x_n(t)\big).
\label{mam}
\end{equation}
The \textit{velocity difference multi-anticipative} (VDMA) model includes speed difference terms
\begin{equation}\textstyle
F_k =\alpha _k \left[\frac1{T_1}\big(V\left(\Delta x_{n,k}(t)/k\right)-\dot x_n\big) +
\frac1{T_2}\Delta\dot x_{n+k}(t)\right].
\label{vdmam}
\end{equation}
Here the positive coefficients $(\alpha_k)$ are such that $\sum_k\alpha_k=1$.
They specify the interaction with the predecessors.
In the following we set $\alpha_k=1/K$ for all $k$ (uniform interaction) in order to maximise the stability  \cite{Lenz1999,Hasebe2003}.
Note that the MA model is the OV one and the VDMA model is the FVD one for $K=1$, while the VDMA model is the MA one at the limit
$T_2\rightarrow\infty$.
The tested models are resumed is table~\ref{res}.
\begin{table}[!ht]\begin{center}\begin{tabular}{l|l|l|l}
Name&$\ $Acronym$\ $&$\ $Type&$\ $Parameter\\[1mm]
\hline
&&&\\[-2mm]
Optimal velocity&$\ $OV&$\ $Autonomous$\ $&$\ V'$, $T$\\[0mm]
Full velocity difference&$\ $FVD$\ $&$\ $Autonomous&$\ V'$, $T_1$, $T_2$\\[0mm]
Multi-anticipative&$\ $MA&$\ $Collective&$\ V'$, $T$, $K$\\[0mm]
Velocity difference multi-anticipative$\ $&$\ $VDMA&$\ $Collective&$\ V'$, $T_1$, $T_2$, $K$
\end{tabular} \caption{Name, acronym, type and parameters of the tested models.}\label{res}\vspace{-2mm}\end{center}\end{table}

\section{Simulation of a jam} \label{sim}
In this section, the models (\ref{ovm}), (\ref{fvdm}), (\ref{mam}) and (\ref{vdmam}) are simulated
with periodic boundary conditions from jam initial conditions by using explicit Euler schemes with time step 0.001 s.
$N=20$ vehicles are considered with the settings: $V'=1\ $s$^{-1}$~, $T=T_1=0.25\ $s (fix), and $T_2=2$, $0.5$, $0.1\ $s~, $K=2$, $4$, $10\ $veh (tested).
The settings are defined so that the LSNO and GS conditions occur for any model.
The trajectories obtained with OV and FVD autonomous models are presented in figure~\ref{trajFVDM}.
The convergence speed to the homogeneous solutions increases as $T_2\rightarrow0$.
The same phenomenon occurs with MA model as $K\rightarrow\infty$, see figure~\ref{trajMAM}.
However, there is no clear improvements of the stability with the VDMA model
if $T_2$ is sufficiently small (see figure~\ref{trajVDMAM}).

\begin{figure}[!ht]\begin{center}\vspace{-7mm}
\includegraphics[width=6.5cm]{trajOVM.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajFVDMt22.pdf}\\[-15mm]
\includegraphics[width=6.5cm]{trajFVDMt205.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajFVDMt201.pdf}
\caption{Trajectories with the OV and FVD models from jam initial configuration.}
\label{trajFVDM
\end{center}\end{figure}

\begin{figure}[!ht]\begin{center}\vspace{-5mm}
\includegraphics[width=6.5cm]{trajOVM.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajMAMk2.pdf}\\[-15mm]
\includegraphics[width=6.5cm]{trajMAMk4.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajMAMk10.pdf}
\caption{Trajectories with the OV and MA models from jam initial configuration.}
\label{trajMAM}\vspace{0mm}
\end{center}\end{figure}

\begin{figure}[!ht]\begin{center}\vspace{-5mm}
\includegraphics[width=6.5cm]{trajFVDMt201b.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajVDMAMk2.pdf}\\[-15mm]
\includegraphics[width=6.5cm]{trajVDMAMk4.pdf}\hspace{-15mm}\includegraphics[width=6.5cm]{trajVDMAMk10.pdf}
\caption{Trajectories with the FVD and VDMA models from jam initial configuration.}
\label{trajVDMAM}\vspace{-10mm}
\end{center}\end{figure}

The speed of convergence of the system to the uniform solution can be quantified by spacing standard deviation sequence (Lyapunov function)~:
\begin{equation}\textstyle\textstyle
\sigma_{\Delta x}=\sqrt{\frac1N\sum_{n=1}^N\left(\Delta x_n-\Delta \bar{x}_n\right)^2}\qquad\mbox{with}\quad \Delta \bar{x}_n=\frac1N\sum_{n=1}^N\Delta x_n.
\end{equation}
In the figure~\ref{stddev}, the logarithms of the spacing standard deviation are plotted according to the time for the different models.
We observe linear evolution, meaning that the deviation tend to zero with exponential speed.
As expected, the slope of the logarithm (i.e. the convergence speed) increases as $T_2$ decreases with the autonomous models
(see figure~\ref{stddev}, top left panel), while the speed depends on the number of predecessors in interaction $K$
with the collective MA model (see figure~\ref{stddev}, top right panel).
As we observed previously, the speed does not change significantly if $K$ increases with VDMA model (see figure~\ref{stddev}, bottom left panel).
In fact the speeds of convergence of FVD, MA, and VDMA models are close (see figure~\ref{stddev}, bottom right panel);
they are strongly faster than the convergence speed of ordinary OV model.
Such results suggest that speed difference term with the autonomous models and the number of predecessors in interaction with the collective ones
have similar roles in the dynamics.
The convergence speed to the homogeneous solution is maximised as $T_2\rightarrow0$ or as $K\rightarrow\infty$.

\begin{figure}[!ht]\begin{center}\vspace{-7mm}
\includegraphics[width=6cm]{stddev1.pdf}\hspace{-10mm}\includegraphics[width=6cm]{stddev2.pdf}\\[-10mm]
\includegraphics[width=6cm]{stddev3.pdf}\hspace{-10mm}\includegraphics[width=6cm]{stddev4.pdf}
\caption{Sequences of the spacing standard deviation logarithm with OV, FVD, MA and VDMA models.}
\label{stddev}\vspace{-12mm}
\end{center}\end{figure}

\section{Lyapunov exponents} \label{exp}

The solution of the linear systems are linear combination (LC) of exponential terms
\begin{equation}\textstyle
x_n(t)=\mbox{LC}\big(\exp(\lambda_lt),t\exp(\lambda_lt)\big)
\end{equation}
with $(\lambda_l)$ the Lyapunov exponents of the system (i.e. the eigenvalues of the system Jacobian matrix).
In our stable case, all the exponents have strictly negative real parts, excepted one equal to zero.
Moreover, we can expect than the convergence to the homogeneous solution gets faster as the exponents go the
left of the imaginary axis.
With the optimal velocity we investigate, the exponents are~:
\begin{equation}\textstyle
\lambda_l=\frac12\sum_{k=0}^K\beta_k \iota_l^k\pm\frac12\Big[\left(\sum_{k=0}^K\beta_k\iota_l^k\right)^2-4\sum_{k=1}^K\alpha_k(1-\iota_l^k)\Big]^{1/2}
\end{equation}
with $\iota_l=\exp(2i\pi l/N)$, $l=1,\ldots N$, $N$ being the vehicles number,
$\alpha_k=\frac{1}{kT_1}\frac{V'}{K}$, $\beta_0=-\frac1{T_1}-\frac1{T_2}$ and
$\beta_k=-\frac1{KT_2}$ for all $k=1,\ldots N$.
The Lyapunov exponents are plotted in figure~\ref{exp1} for the different models.
We observe that they converge to a double mode pattern as $T_2\rightarrow0$ with the autonomous FVD model,
and $K\rightarrow\infty$ with the MA collective model.
They remain double mode with the collective VDMA model as $K$ increases.
Such results confirm qualitatively the ones observed by simulation
The speed difference behave in the dynamics as the number of predecessors in interaction.
Also increasing the interaction seems not necessary to maximise the stability.

\begin{figure}[!ht]\begin{center}\vspace{-0mm}
\includegraphics[width=\textwidth]{lypexp.pdf}
\caption{Lyapunov exponents for OV, FVD (top panels), MA  (middle panels) and VDMA (bottom panels) models with $N=100$.}
\label{exp1}\vspace{-12mm}
\end{center}\end{figure}

\section{Conclusion} \label{ccl}

The convergences to the homogeneous solution of linear jam avoidance OV models are compared.
We observed that extending the OV model with speed difference term
significantly improves the stability.
In a similar way, the adding of neighbours in interaction gives stability enhancements.
However, increasing the interaction does not improve the stability with the extended OV model.
This suggests that both the number of predecessors in interaction in the collective models and
the speed difference term in the autonomous approaches allow to maximise the convergence speed to homogeneous solutions.
Also, the connection between the vehicles, hard to implement, may not be necessary to optimise the stability
and efficiently avoid jam formation.
Further investigations remain to be carried out to validate this hypothesis.
For instance, the influence of the geometry, initial conditions or vehicle density have to be investigated.
The shape of the Lyapunov exponents and their impact on the stability are not explicit.
Furthermore, non-linear models may present better convergence speed than the basic linear models we analysed.
These subjects will the topic of future works.

\bibliographystyle{spmpsci

redpajama_set_name: RedPajamaArXiv


According to the World Israel News Network on the 15th, the original source of the news came from a Syrian anti-government website, which said a Russian delegation took a coffin containing Cohens remains when it left Syria. Reported that since Israeli officials announced earlier this month that Israeli sergeant Zakari Bommel, who disappeared during the Lebanese War in 1982, was rediscovered 37 years later with the assistance of Russia, news began to circulate in social media that Eli Cohens remains were about to return to Israel.
Born in 1924, Cohen is a Jew born in Egypt. He is proficient in Arabic, Hebrew, French and Spanish. In the early 1950s, he was recruited as a special agent by Mossad. After several years of training, he went to Argentina in 1960 as an Arab importer and exporter named Kamel Amin Tabes. Shortly afterwards, at a reception hosted by the Syrian Embassy, Cohen met Hafez Assad, then the military officer of the embassy and later the president of Syria, and entered the upper-class society. The highest official, the member of the National Revolutionary Committee of the Syrian ruling party, became the main adviser to the Minister of Defence, and almost became the Minister of Defence. During the incubation period, Cohen proposed planting trees around the fortress in the Golan Heights to make a contribution to Israels future seizure of the Heights. Cohen was hanged at Martyrs Square in Damascus in 1965 after being identified as a spy.
[Global Network Military Comprehensive Report] Legendary Israeli spies are on their way home. According to the Israeli Jerusalem Post on the 15th, there are many rumors that the body of Israeli spy Eli Cohen, who successfully penetrated high-level Syria and was executed after being identified, is about to return to Israel with the help of Russia. However, the official did not respond to the news.