Allied offensives, 1943–44 Pacific War

the allied leaders of asian , pacific theaters: generalissimo chiang kai-shek, franklin d. roosevelt, , winston churchill meeting @ cairo conference in 1943

midway proved last great naval battle 2 years. united states used ensuing period turn vast industrial potential increased numbers of ships, planes, , trained aircrew. @ same time, japan, lacking adequate industrial base or technological strategy, aircrew training program, or adequate naval resources , commerce defense, fell further , further behind. in strategic terms allies began long movement across pacific, seizing 1 island base after another. not every japanese stronghold had captured; some, truk, rabaul, , formosa, neutralized air attack , bypassed. goal close japan itself, launch massive strategic air attacks, improve submarine blockade, , (only if necessary) execute invasion.

in november 1943 marines sustained high casualties when overwhelmed 4,500-strong garrison @ tarawa. helped allies improve techniques of amphibious landings, learning mistakes , implementing changes such thorough pre-emptive bombings , bombardment, more careful planning regarding tides , landing craft schedules, , better overall coordination.

the navy did not seek out japanese fleet decisive battle, mahanian doctrine suggest (and japan hoped); allied advance stopped japanese naval attack, oil shortages (induced submarine attack) made impossible.

submarine warfare

us submarines, british , dutch vessels, operating bases @ cavite in philippines (1941–42); fremantle , brisbane, australia; pearl harbor; trincomalee, ceylon; midway; , later guam, played major role in defeating japan, though submarines made small proportion of allied navies—less 2 percent in case of navy. submarines strangled japan sinking merchant fleet, intercepting many troop transports, , cutting off oil imports essential weapons production , military operations. 1945, japanese oil supplies limited fleet virtually stranded.

the japanese military claimed defenses sank 468 allied submarines during war. in reality, 42 american submarines sunk in pacific due hostile action, 10 others lost in accidents or result of friendly fire. dutch lost 5 submarines due japanese attack or minefields, , british lost three.

the torpedoed japanese destroyer yamakaze, seen through periscope of american submarine, nautilus, in june 1942

american submarines accounted 56% of japanese merchantmen sunk; mines or aircraft destroyed of rest. american submariners claimed 28% of japanese warships destroyed. furthermore, played important reconnaissance roles, @ battles of philippine sea (june 1944) , leyte gulf (october 1944) (and, coincidentally, @ midway in june 1942), when gave accurate , timely warning of approach of japanese fleet. submarines rescued hundreds of downed fliers, including future president george h. w. bush.

allied submarines did not adopt defensive posture , wait enemy attack. within hours of pearl harbor attack, in retribution against japan, roosevelt promulgated new doctrine: unrestricted submarine warfare against japan. meant sinking warship, commercial vessel, or passenger ship in axis-controlled waters, without warning , without aiding survivors. @ outbreak of war in pacific, dutch admiral in charge of naval defense of east indies, conrad helfrich, gave instructions wage war aggressively. small force of submarines sank more japanese ships in first weeks of war entire british , navies together, exploit earned him nickname ship-a-day helfrich . dutch force in fact first sink enemy warship; on 24 december 1941, hnlms k xvi torpedoed , sank japanese destroyer sagiri.

while japan had large number of submarines, did not make significant impact on war. in 1942, japanese fleet submarines performed well, knocking out or damaging many allied warships. however, imperial japanese navy (and pre-war us) doctrine stipulated fleet battles, not guerre de course (commerce raiding) win naval campaigns. so, while had unusually long supply line between west coast , frontline areas, leaving vulnerable submarine attack, japan used submarines long-range reconnaissance , attacked supply lines. japanese submarine offensive against australia in 1942 , 1943 achieved little.

as war turned against japan, ijn submarines increasingly served resupply strongholds had been cut off, such truk , rabaul. in addition, japan honored neutrality treaty soviet union , ignored american freighters shipping millions of tons of military supplies san francisco vladivostok, consternation of german ally.

the i-400 class, largest non-nuclear submarines ever constructed

the navy, contrast, relied on commerce raiding outset. however, problem of allied forces surrounded in philippines, during part of 1942, led diversion of boats guerrilla submarine missions. basing in australia placed boats under japanese aerial threat while en route patrol areas, reducing effectiveness, , nimitz relied on submarines close surveillance of enemy bases. furthermore, standard-issue mark 14 torpedo , mark vi exploder both proved defective, problems not corrected until september 1943. worst of all, before war, uninformed customs officer had seized copy of japanese merchant marine code (called maru code in usn), not knowing office of naval intelligence (oni) had broken it. japanese promptly changed it, , new code not broken again op-20-g until 1943.

thus, in 1944 did navy begin use 150 submarines maximum effect: installing effective shipboard radar, replacing commanders deemed lacking in aggression, , fixing faults in torpedoes. japanese commerce protection shiftless beyond description, template:notetag , convoys poorly organized , defended compared allied ones, product of flawed ijn doctrine , training – errors concealed american faults as japanese overconfidence. number of american submarines patrols (and sinkings) rose steeply: 350 patrols (180 ships sunk) in 1942, 350 (335) in 1943, , 520 (603) in 1944. 1945, sinkings of japanese vessels had decreased because few targets dared venture out on high seas. in all, allied submarines destroyed 1,200 merchant ships – 5 million tons of shipping. small cargo carriers, 124 tankers bringing desperately needed oil east indies. 320 passenger ships , troop transports. @ critical stages of guadalcanal, saipan, , leyte campaigns, thousands of japanese troops killed or diverted needed. on 200 warships sunk, ranging many auxiliaries , destroyers 1 battleship , no fewer 8 carriers.

underwater warfare dangerous; of 16,000 americans went out on patrol, 3,500 (22%) never returned, highest casualty rate of american force in world war ii. joint army–navy assessment committee assessed submarine credits. japanese losses, 130 submarines in all, higher.

cite error: there <ref group=lower-alpha> tags or {{efn}} templates on page, references not show without {{reflist|group=lower-alpha}} template or {{notelist}} template (see page).