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Battle of Iwo Jima - 19451 - WWII LVT Museum

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Visited 2-11-11

Operation Detachment, the Marine Invasion of Iwo Jima


Photo of the invasion of Iwo Jima on D-Day

Invasion of Iwo Jima on February 19, 1945. U.S. Navy photo.

The island of Iwo Jima, located 650 miles south of the Japanese main islands, was considered to be a part of Tokyo. It was used by the Japanese as an advanced early-warning radar station which would give them two hours notice against bomber raids on Japan itself. Iwo Jima also had an airfield that would allow Japanese fighters to intercept Allied bombers.


The Japanese Build-up on Iwo Jima

With the capture of the Marianas Islands by the U.S. and other Allied successes throughout the south Pacific, Japan was strengthening her presence on Iwo Jima. By the end of 1944, the Japanese garrison on Iwo Jima was 20,000 men, 360 pieces of artillery, 75 heavy and medium mortars, 33 naval guns, 94 anti-aircraft guns, approximately 300 anti-boat guns and 70 rocket-launching projectiles ranging from 200 to 550 pounds.


The island was bombarded with naval and air strikes for several months prior to the Allied invasion (code name Detachment) on February 1945. Unfortunately, this caused little destruction to the defensive positions.


Launch Time and Advance of the Amphibian Tractors

Launch time was 0725, on February 19, 1945, and within 20 minutes, 448 amphibian tractors were afloat and moving towards the line of departure. At 0805, 72 carrier planes bombed Mt. Surabachi and the beaches, which was followed by the advance of the armored and then troop carrying amtracs toward the island. At 0902 the armored LVTs reached the beaches, followed two minutes later by the troop carrying LVTs. The infantry disembarked, and the LVTs returned to their LSTs to load supplies. Within 30 minutes of the first assault wave's landing, eight infantry battalions had been landed and were fighting their way inland.


The Japanese did not respond until five minutes after the fist wave landed on Beaches Yellow. Then enemy mortar and artillery fire became intense, hitting boats, LVTs and shore parties directing traffic.


The 4th and 5th MarDiv


Photo of damaged LVTs and other vehicles on Iwo Jima

Damaged LVTs and other vehicles on Iwo Jima. U.S. Navy photo.

The 4th and 5th MarDiv landed four regiments abreast over six of seven designated beaches, totaling 3,500 yards on the southeast side of the island. The 5th MarDiv landed under the shadow of Mt. Surabachi, placing the 28th Regiment on Beach Green, and the 27th Marines on Beaches Red 1 and 2. The 4th MarDiv landed against the island's main defenses. The 23rd Marines came ashore on Beaches Yellow 1 and 2, and the 25th Marines on Beach Blue 2. The 3rd MarDiv was in reserve on board ship.


On the 5th MarDiv front, the assault was lead by 34 armored LVT(A)4s from C and D Companies of the 2nd Armored Amphibian Battalion. The 28th Marines came ashore in 93 amtracs of the 11th Amtrac Battalion, and the 27th Marines in 90 amtracs of the 3rd Amtrac Battalion.

The 4th MarDiv received their lead support from A and B Companies of the 2nd Armored Amtrac Battalion as well, landing the 25th Marines in 94 amtracs from the 5th Amtrac Battalion and 94 amtracs of the from the 10th Amtrac Batallion landing the 23rd Marines.




Documentary on the WWII Battle for Iwo Jima in 1944. Produced by the U.S. Government Office of War Information. Twenty minutes.

The 2nd Amphibian Battalion was comprised of four companies equipped with 17 LVT(A)4s and two cargo LVTs modified as maintenance and supply support. The four cargo amtrac battalions shared 181 LVT(2)s and 222 LVT(4)s. Of the 403 LVTs, 380 were used in the assault phase, and the remaining 23 were retained as battalion support vehicles. The next morning, February 20, the 28th Marines climbed Mt. Surabachi.


The Regiment had suffered 385 casualties on the first day ashore and the climb up Surabachi would take four days and cost another 510 men. The US flag was placed at the summit on February 23, and at 1600 on March 16, 1945, Iwo Jima was officially secured.


Casualties on Iwo Jima

Casualties on Iwo Jima totaled 22,000 Marines and 3,000 navy personnel. Of the 20,000 Japanese in defense of the island, only one percent survived as prisoners.


D-Day loses were light among the 448 amtracs in the assault landings. Only one LVT(a)4 was destroyed by Japanese fire, whereas two hours after hitting the beaches, 7 more LVT(A)4s were knocked out.


The 2nd Armored Amphibian Battalion suffered 67 casualties and lost 20 LVT(A)4s during fire support missions, night time beach defenses, and patrolling of the coast. 13 were lost to enemy fire and 16 sank due to mechanical failure or lack of fuel. Five LVT(A)4s were lost when LSTs refused to provide fuel or allow them aboard the vehicles.


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This refusal to provide fuel came about because so many LST crews were giving fuel only to their own LVTs, not wanting to run out by supplying other LVTs. Most of the experienced LST crews had been sent to the Philippines and Iwo Jima had green crews whose indoctrination was not complete.2 Without fuel, the LVTs could not return to shore and if they had been hit and were taking on water, they would eventually sink since the bilge pumps were gas operated.


Cargo amtracs of the 10th Amtrac Battalion shuttled ammunition after dark to forward positions, requiring them to pass through heavily mined areas that had already claimed several of the battalion's amtracs. Amtrac loses totaled 1/3 of those landed, of which 14% were lost to enemy fire, 23% lost to heavy surf, 4% lost to mines, and 50% were lost through sinking. Personnel losses among the four cargo battalion numbered 122, approximately 20%.


Among the Americans who served on Iwo Jima, uncommon valor was a common virtue, Fleet Admiral Nimitz during the battle of Iwo Jima.


Amphibian Units ~ Battle of Iwo Jima, D-Day February 19451

3rd Amphibian Tractor Battalion
(90) LVT-2s
5th Amphibian Tractor Battalion (94) LVT-2s
10th Amphibian Tractor Battalion (94) LVT-2s
11th Amphibian Tractor Battalion (93) LVT-2s

Notes:
1Information for this article is based on text from signs at the WWII Korean LVT Museum at Camp Del Mar Marine Corps Base, Camp Pendleton, California, except where otherwise noted.

2Major Alfred Dunlop Bailey, USMC (Retired). Alligators, Buffaloes, and Bushmasters, The History of the Development of the LVT Through World War II. Washington, D.C.: History and Museums; U.S. Marine Corps, 1986, p.206.



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