1. Sea Power and Maritime Affairs Lesson 12: The US Navy in the Pacific, 1941-1945

2. Learning Objectives Comprehend the political and economic forces that led Japan to strike at Pearl Harbor and the Far East. Comprehend the Japanese strategy for an early victory and their concept of the postwar Pacific power balance. Comprehend the impact of Pearl Harbor and the subsequent Battles of Coral Sea and Midway on the transformation of the aircraft carrier's role in naval warfare. Know the significant highlights of the evolution of US operational strategy in the Pacific, including major battles or campaigns and instances where strategy was flawed or ambiguous. Know the strategic significance of the employment and refinement of amphibious landing tactics by the US Navy and US Marine Corps. Comprehend the reasons the geopolitical world order was changed as a result of Japan’s actions in striking at the Western powers in 1941.

3. Background Information Japanese-American Relations tense: Japan challenged America’s “Open Door” policy by attacking Manchuria in 1931. In 1937, Japanese expansion in China resulted in attack on American gunboat, the Panay, by Japanese aircraft. Roosevelt adopted economic sanctions leading to an oil embargo by Americans, British and Dutch (July 1941)

4. Background Information The Japanese struck for the oil- rich Dutch East Indies(Indonesia), Singapore, and the surrounding British- owned Malaya, Thailand, the Philippines, and Hong Kong. The Japanese camouflaged their plans with diplomatic negotiations in Washington. The United States expected an assault somewhere in the Pacific because cryptanalysts, in a technique called “Magic,” had broken the Japanese Diplomatic Code.

5. Background Information The attack on Pearl Harbor surprised the Americans, who had not anticipated a strike so far east or one mounted solely by carrier-born aircraft.

6. Japan WWII Strategy Secure Resources in Southeast Asia Create Greater East Asia Co-prosperity Sphere (Like Asuan Monroe Doctrine) Attempt to Fight Limited War (Pearl Harbor is major error) Create defense perimeter to force costly frontal assualts Negotiate when the US is exhausted/frustrated by casualties

7. Pearl Harbor: Japan’s Plan Southern drive into Indochina and Dutch East Indies for oil. Strike at Philippines and Singapore to knock out local American and British Forces.

8. US WWII Strategy Secure line of Communications to Australia – Solomons/ Guadal Canal (6 month campaign) Two Pronged Offensive: South and Central Pacific – Meet at Philippines Island Hopping/ Leapfrogging

9. US WWII Strategy Island Hopping/ Leapfrogging – Rather than engage sizable Japanese garrisons, these operations were designed to cut them off – let them "whither on the vine.” – approach of bypassing Japanese strong points, such as Truk, was applied on a large scale as Allies moved across the central Pacific. – Known as "island hopping," US forces moved from island to island, using each as a base for capturing the next. – Seized one or two key Islands in a chain, destroyed Japanese air and naval units on neighboring Islands – Japanese troops were thus isolated, unable to affect the war – Far fewer US casualties and less time than Japanese anticipated

10. US WWII Strategy Key is Fast Carrier Striking force – Large Aircraft Carriers (CV) of 20,000 – 33,000 tons with 80 – 100 Aircraft and over 30 knots speed – Enormous firepower (60 bomber aircraft with bombs or torpedoes – Vulnerability is wooden flight decks, fire danger when hit Tactics – carrier raids hit and run – carrier versus carrier battles – amphibious landing support. Forces at the Start of WWII – Japan 10 CV’s:; US has 7 CV’s

11. US WWII Strategy US Advantages – Produce more ships and have more man-power – US builds 14 CV’s, 10 BB’s dozens of Cruisers and Destroyers and Dozens of Escort and Light Carriers – Japan only 4 CV’s, 10 Light Carriers MAGIC program allows US to read Japanese Codes – Not completely deciphered but critical to US victory Radar installed on most US ships and used for fire control – Also used by submarines

12. Japanese Advantages Early Air superiority – Planes are faster, more maneuverable, but vulnerable due to lack of armor and self sealing gas tanks – Superior Night vision devices at start of war – More Aircraft carriers at start of War – Larger surface ships BB’s, CA,s DD’s due to Washington Treaty violations before WWII – Better torpedoes and these torpedoes were mounted on CA’s as well as DD’s (Critical during Guadalcanal/Solomons Campaign)

13. Pearl Harbor

14. Pearl Harbor — Japanese Plans Attack on Pearl Harbor conceived by Admiral Yamamoto: – Great risk — U.S. would surely enter the war. – Greater potential gain — U.S. Pacific Fleet would be knocked out of the war. Japan would then consolidate gains throughout China and the Pacific. Possibility of U.S. agreeing to Japanese territorial gains to make peace. – Good possibility of U.S. involvement in Europe as well. Will drain naval resources from Pacific Ocean. U.S. Atlantic Fleet already involved in convoy escort against U-boats.

16. The Attack

17. Aftermath of Pearl Harbor Battleship fleet effectively destroyed Carriers survive and become new capital ships – Submarines, repair facilities, and oil tanks also left unharmed by attack Result generally not anticipated by American naval planners before Pearl Harbor – Naval tactics change to support carrier strikes – Circular formations developed to protect carriers

18. Aftermath of Pearl Harbor U.S. declares war on Japan – “Day of Infamy” - Franklin Delano Roosevelt Hitler declares war on the U.S. American public opinion changes in favor of war

19. U.S. Defensive Organization/ Plans Admiral Chester W. Nimitz relieves Kimmel as Commander in Chief, U.S. Pacific Fleet Nimitz - Commander in Chief Pacific Ocean Areas – Includes North, Central, and South Pacific Areas MacArthur - Commander in Chief Southwest Pacific Area – Australia, New Guineau, East Indies, and Philippines – Fleet elements in this zone remained under Nimitz's control

20. U.S. Defensive Organization/ Plans Controversial command structure – No common superior -- two separate wars in the Pacific Overwhelming U.S. industrial and logistical superiority – Allows divided command until forces converge on Philippines in 1944

21. Island Hopping MacArthur leapfrogs up coast of New Guinea Nimitz Island Hopping across central Pacific Goal is to create secure supply line to seize Marianas Islands – Establish airfields there for long range bombers to attack Japan then Meet MacArthur at the Phillipines Despite “Germany First” Policy the Two Commanders get all the resources they need

23. Submarines in the Pacific Unrestricted Submarine Warfare – Commences against Japan immediately following Pearl Harbor attack by order of CNO Admiral King. “We shall never forget that it was our submarines that held the lines against the enemy while our fleets replaced losses and repaired wounds.” - Fleet Admiral Chester Nimitz, 1947

24. U.S. Submarine Warfare Simultaneously with Dual advance, US conducts war on commerce Unrestricted Submarine Warfare ordered immediately after Pearl Harbor -- new role for U.S. submarines Early operational problems - 1942-43: – Undependable torpedoes - poorly designed magnetic fusing. Refuse to test them ($10,000 a piece) Many commanders were excessively cautious. US Fleet subs best of the war – 55 Days at sea, 24 torpedoes, fast diving, air conditioned

25. U.S. Submarine Warfare Don’t fix problems to 1943 – 1/3 of Commanders relieved and replaced with aggressive younger ones – Abandon scout role and switch to night attacks – Target all ships Eventually emphasize oil tankers – Finally fix torpedoes that ran too deep and failed to explode 1944 have good equipment, right doctrine – Also crack the Japanese Merchant ship code (Maru Code) – Japanese refuse to convoy (defensive war is not consistent with Warrior Code – Refuse to build escorts until 1943 – By 1945 Japanese Merchant Marine is totally destroyed

26. Japanese Submarine Warfare Long Lance torpedo - smaller variant for submarines I-Boat is big, slow to submerge and noisy Focused attacks on U.S. warships and avoided supply ships – Used to screen and scout for battle fleets – “Warrior ethos” of Japanese naval leaders Used for supply of bypassed garrisons and “exotic” missions

27. Japanese Submarine Warfare Battle of Midway – Failed to intercept U.S. carrier forces – Torpedoed USS Yorktown under tow Guadalcanal Campaign – USS Saratoga torpedoed January 1942 – USS Wasp sunk USS Indianapolis sunk -- July 1945 - shark attacks

28. Mitsubishi A6M “Zero”

29. TBD-1 Devastator Torpedo Bombers

30. USS Yorktown (CV 5) SBD-3 Dauntless Dive Bombers

31. F4F Wildcats

32. USS Enterprise (CV 6)

33. USS Hornet (CV 8) Captain Marc Mitscher, Commanding Officer

34. USS Yorktown (CV 5) Damaged by air strikes on 4 June. Sunk by submarine torpedo attack on 7 June.

37. Japanese Carriers Kaga, Akagi, and Soryu

40. USS Yorktown (CV 5)

43. Break Time……………. When We Resume: The US Navy and the Offensive Phase

44. A6M “Zero” or “Zeke” Fighter

45. U.S. Aircraft Production Japan and Germany had early advantage in air war: – Messerschmit ME-109 – Mitsubishi A6M Zero U.S. aircraft industry produces higher performance aircraft – American industrial base allows rapid and mass production New flight training programs developed U.S. gains advantage in air warfare Air supremacy eventually established in both European and Pacific theaters

46. F2A “Buffalo” Fighter

47. F4F “Wildcat” Fighter

48. Wildcats on the Prowl

49. F6F “Hellcat” Fighter

50. F4U Corsair Fighter

51. SBD “Dauntless” Dive Bomber

52. SB2C “Helldiver” Dive Bomber

53. TBF “Avenger” Torpedo Bomber

54. PBY “Catalina” Scout

57. Prelude to Guadalcanal Japanese leadership shocked by defeat at Midway Cancel plans to take Fiji, Samoa, and New Caledonia Must proceed with plan to take Port Moresby Within bomber range of major naval operating base at Rabaul Japanese begin building airfield at Guadalcanal

58. Prelude to Guadalcanal Nimitz moves to reinforce South Pacific Area – Protect vital sea lines of communication with Australia. – Vice Admiral Robert L. Ghormley Commander South Pacific Ocean Area (Subordinate to Nimitz). – Two bases established in New Hebrides.

59. Army - Navy Dispute MacArthur proposes retaking Rabaul – Wants Navy to let him borrow First Marine Division Admiral King – Objects to Macarthur's plan – Proposes step-by-step advance through Solomons to re-take Rabaul. – Nimitz and Ghormley in command with Marines making amphibious assaults and Navy providing support. Army forces used as garrisons for islands

60. Operation Watchtower Compromise Three-Stage Plan of Operations Initial advance in Eastern Solomons under Nimitz Boundary between Areas moved west MacArthur takes command after Tulagi secured

62. Gudalcanal Campaign Aug 1942-Feb 1943

63. Whoever controlled an airfield would control air over the Solomons Vital SLOC For both sides it symbolized offensive rather than defensive warfare Guadalcanal

64. Force Commanders Admiral Robert L. Ghormley overall command of Watchtower Rear Admiral Richmond Kelly Turner - Amphibious Forces Vice Admiral Frank Jack Fletcher carrier group – Provided support against Japanese fleet during day

65. General Archer Vandegrift Commander - First Marine Division Amphibious landing virtually unopposed – Marines take Henderson Field - “Cactus Air Force”.

67. Guadalcanal River Crossing

68. “See-Saw” Pattern Japan dominates nighttime action. – “Tokyo Express” down “The Slot” into “Ironbottom Sound” U.S. dominates daytime with shore and carrier aircraft

69. Actions Battle of Savo Island, 8-9 August 1942 Battle of the Eastern Solomons, 24 August 1942 Battle of the Santa Cruz Islands, 26-27 October, 1942 “Naval Battle of Gudalcanal”, 12-13 November, 1942

70. Guadalcanal Campaign Battle of Savo Island - Allies defeated in night surface action Battle of the Eastern Solomons - carrier battle – USS Enterprise damaged by bombers – USS Wasp sunk and Saratoga damaged by Japanese submarines

71. Battle of Santa Cruz Islands Halsey relieves Ghormley - 18 October 1942 Rear Admiral Thomas C. Kinkaid Hornet sunk and Enterprise damaged – No operational carriers left Zuiho and Shokaku badly damaged Tactical defeat by strategic victory?…maybe

72. Naval Battle Rear Admiral Willis A. Lee – uses RADAR to his advantage to win nighttime naval battle Washington and South Dakota outfight Japanese battleships – Warships flee – Transports beach themselves

73. Guadalcanal Campaign 1st Marine Division relieved by Army’s 25th Infantry Division Japanese forces evacuate Guadalcanal U.S. forces begin advance up Solomon Islands – Land-based airfields established Marine Corps’ “Black Sheep” Squadron (VMF-214) –Commanded by Maj Greg “Pappy” Boyington Medal of Honor Recipient MacArthur drives Japanese from eastern Papua – Captures main Japanese base at Buna

74. Aftermath Both sides suffered heavy losses – U.S loses more tonnage at sea, carriers – Japan loses more lives Japan allowed to dominate sea at night while U.S. dominates day Battle drags on from Aug 42- Feb 43

75. Aftermath MacArthur successful in driving Japanese from Papuan Peninsula – By Feb 43 Jap plans for offensives in S. and W Pacific stopped cold King uses Casablanca Conference to allocate more resources to Pacific

76. Reconquest of Attu and Kiska Aleutian Islands (January - May 1943) No real threat to security. Necessary to end Japanese control of American territory for political reasons. Battle of the Komondorskis – Last classic surface ship battle. – Americans attack heavily guarded Japanese convoy. Minimal resistance on Attu, none on Kiska.

77. Operation Cartwheel The Solomons Campaign Halsey goes to work for McArthur – Leads Amphibious Assault from Guadalcanal along Solomons McArthur wants direct assault on Rabaul – King and Marshall overrule him – Capture every island BUT Rabaul to isolate it Rabaul becomes isolated and insignificant – On to the Phillipines (October 1944)

78. The Defeat of Japan Objective: The Philippines and the penetration of the Japanese inner defense zone!

79. The Advance Pacific “Thrust” – Amphib support Vice Admiral Raymond Spruance Significant campaigns: – Gilberts – Marshalls – Marianas

80. Essex Class Fast Carrier

81. The Gilberts (Tarawa) New fleet organization due to new Essex Class carrier fleet production Objective to gain airfield on Betio Island to launch further attacks in Central Pacific Drive 3 days cost US > 3,000 marines

82. Marines at Tarawa

83. Tarawa Kwajalein Atoll

84. The Marshalls After the Gilberts, concern for death toll in Marshalls Nimitz orders RADM MITSCHER attack on Airpower – Destroys Japanese Force Kwajalein success furthers to the rest of the islands Total Marshall loss less than first day of Tarawa Onto Marianas

85. The Marianas Draws out Japanese Fleet Battle of Philippine Sea, 19-20 June 1944 “The Great Marianas Turkey Shoot” – 346 Jap planes downed – 3 Jap carriers sunk – Classic Mahanian engagement

86. Liberation of the Philippines U.S. advance continues after Marianas Campaign – Macarthur's forces capture New Guinea Air strikes in the Phillipines wipe out two hundred aircraft Bypass smaller islands and head to Leyte Gulf early – from 20 December to 20 October

87. Battle of Leyte Gulf

88. Battle of Leyte Gulf 24-25 October 1944 Largest battle in all of naval history U.S. command structure remains divided and confused U.S. landings in Leyte Gulf – MacArthur “returns”

90. Battle of Leyte Gulf “In case opportunity for destruction of the major portion of the enemy fleet is offered or can be created, such destruction becomes the primary task.” -- Standing Order of Fleet Admiral Nimitz “Where is, repeat where is, Task Force 34? The world wonders.” -- Nimitz’ (message to Halsey during the battle.)

91. Admiral Marc Mitscher Commander Fast Carrier Task Force Battle of Leyte Gulf

92. Japanese Combined Fleet divided into three forces: – Northern – Central – Southern Japanese defeated in a series of separate engagements. – Effective end of Japanese Navy’s ability to control the sea.

95. Battle of Leyte Gulf

96. Japanese Kamikaze Squadrons Explosives loaded aboard aircraft. Japanese pilots fly one-way suicide attack missions against U.S. fleet. First used at Leyte Gulf.

98. USS Lexington (CV 16) Essex Class Fast Carrier Mitscher’s Flagship -- Battle of Leyte Gulf

99. Admiral Thomas Kinkaid Commander U.S. Seventh Fleet Battle of Leyte Gulf

100. The Sands of Iwo Jima Mount Suribachi

101. The Road to Japan Iwo Jima Okinawa

102. Iwo Jima Emergency landing field and fighter escort base desired. – Midway between Marianas and Tokyo – Support B-29 strategic bombing of Japan 26,000 casualties – 2,400 Emergency landings - 27,000 aircrew General Holland Smith – “Iwo Jima was the most savage and most costly battle in the history of the Marine Corps.” Admiral Nimitz – “Uncommon valor was a common virtue.”

103. Okinawa Campaign April-June 1945 Staging base for invasion of Kyushu Joint amphibious operation – Marines under Army command Japanese use delaying tactics at the beach – Continued heavy resistance inland

104. Okinawa Campaign Kamikaze raids continue – 34 U.S. ships sunk – 4,900 Sailors killed in action Over 40,000 U.S. casualties Carrier groups begin raids on Japanese home islands. – U.S. has established complete control of the seas.

105. USS Benjamin Franklin -- Damaged in Kamikaze raid during invasion of Okinawa - March 1945.

106. Japanese Battleship Yamato Sunk by U.S. carrier-based aircraft during Okinawa Campaign. 7 April 1945

107. U.S. Carrier Raids on the Japanese Home Islands July 1945

108. Manhattan Project = Atomic Bombs President Truman orders two bombings. – Hiroshima - 6 August 1945 – Nagasaki - 9 August 1945 Believed potential for casualties during a prolonged struggle for the Japanese home islands is too high.

109. Hiroshima

110. Japan Surrenders Japanese officially surrender aboard USS Missouri in Tokyo Bay on 2 September 1945. MacArthur commands U.S. army of occupation.

111. Discussion Next time: The US Navy in the Early Cold War, 1945-1953