Tarawa: How an Intelligence Failure Led to the Underwater Demolition Teams

DoD Photo
DoD Photo

In 1943, the Allies debated their strategy for taking back the Pacific from the Japanese.  Their strategic goal: the unconditional surrender of Japan.  General Douglas MacArthur slogged his way through the South Pacific, closing with and defeating the heavily entrenched Japanese defenders.  A victory in the South Pacific guaranteed the safey of Australia and the severing of Japan’s southern sea lines of communication, but defeating layered defenses in heavy jungle was slow work.

Was there another way?  Pacific Fleet’s planners thought so.  They proposed a Central Pacific campaign, with the goal of seizing the Marshal Islands.  Seizing the Marshals would assist Gen. MacArthur by cutting off the Japanese in New Guinea, the Solomons, and the Philippines from resupply.  Additionally, the Marshals provided a base from which to launch a campaign against the fortified islands that were needed for air bases in the final invasion of Japan.

But there lay the problem.  The invasion of the Marshals required far more troops than available, at least without disrupting MacArthur’s drive.  Not only was MacArthur’s drive critical to victory, it also had strong political support.  No delay would be tolerated.  But the planners had an answer: the Gilbert Islands.

Requiring significantly fewer troops, the Gilberts lay on the Marshals’ doorstep, and could be used for reconnaissance and basing for a later invasion.  Planners quickly turned their attention to the atolls of Tarawa and Makin, specifically the individual islands of Betio and Butaritari, respectively.  Aerial reconnaissance craft overflew every aspect of the islands, and the USS Nautilus took periscope level photos of the beaches.  Everyone knew that the two atolls’ islands  sat ringed with reefs, but no one seemed to know how deeply those reefs would be submerged on the day of the landing.

Marine casualties lay on the beach of Betio
Marine casualties lay on the beach of Betio. DoD photo.

The staff of Task Force 54, the assault force commander, stated in their orders that no more than one to two feet of clearance would be available at Betio due to a neap tide.  Divisional planners at the 2nd Marine Division interviewed sea captains and former residents of Betio.  With one exception, all stated that there would be enough clearance for the landing craft (LCVPs), which needed at least four feet to navigate safely, to pass.  Planning proceeded based on those interviews.

On November 20, 1943, after an intense naval and aerial bombardment, the Marine landing force began to approach Betio.  The first wave approached in amphibious tractors.  The tractors crawled across the reef, under heavy Japanese fire, and deposited their Marines.  Then the follow-on waves, loaded into LCVPs, began to hit the reef.  As the Task Force 54 staff had predicted, only one to two feet of water was available on the reef line.  The LCPVs grounded.  Marines scrambled from their boats and began to wade hundreds of yards to shore under heavy fire.  Some companies reported losing 35% of their forces before they ever made the beach.

Marines prepare to repatriate the bodies of 36 Marines killed on Tarawa.
In 2015, Marines of the 3rd Marine Regiment repatriated the bodies of 36 Marines killed on Tarawa. Marine Corps photo.

After three days of fighting, the Marines took the island.  Casualties were hastily buried, and a landing strip was built, leaving some Marines buried there, unknown.  Unknown Marines are still being brought home to this day.

Tarawa (and Makin, to a lesser extent) drove home the need for an intelligence gathering and route clearance capability that did not exist in the Navy write large.  The rest, as they say, is history.  According to the UDT/SEAL Museum:

 “[D]uring the Tarawa landing at the Gilbert Islands, a chain of 16 atolls and coral islands in the South Pacific Ocean, a submerged reef caused amphibious landing craft to founder far offshore, resulting in the loss of hundreds of U.S. Marines from enemy fire and drowning. After that experience, Admiral Kelley Turner, Commander of the 5th Amphibious Force, directed that 30 officers and 150 enlisted men be moved to Waimanalo ATB (on the “big island” of Hawaii) to form the nucleus of a reconnaissance and demolition training program. It is here that the UDTs of the Pacific were born.

The first UDT group became UDT-1 and UDT-2, “provisional” UDTs with strengths of about fourteen officers and seventy enlisted men each. They saw their first action on 31 January 1944 in the attacks on Kwajalein and Roy-Namur during Operation FLINTLOCK in the Marshall Islands. Following FLINTLOCK, the UDT men returned to establish a naval combat demolition training and experimental base on a beach near ATB, Kamaol on the island of Maui.

Between December 1944 and August 1945, UDT men saw action across the Pacific in every major amphibious landing, including Eniwetok, Saipan, Guam, Tinian, Angaur, Ulithi, Pelilui, Leyte, Lingayen Gulf, Zambales, Iwo Jima, Okinawa, Labuan, Brunei Bay, and Borneo. On 4 July 1945 at Balikpapan on Borneo, UDT-11 and UDT-18 spearheaded one of the last and least-recorded offensive actions of the war, where they performed their now classic pre-assault reconnaissance and demolition operations.”

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About the author

Joel is a 12 year veteran of the US Coast Guard, where he has served at various units including the International Training Division and Maritime Security Response Team. He has held qualifications including Deployable Team Leader/Instructor, Direct Action Section Team Leader, and Precision Marksman – Observer. He has deployed/instructed on five continents and served in quick reaction force roles for multiple National Special Security Events in the US. He is the owner of Hybrid Defensive Strategies, LLC in Chesapeake, VA, and can be contacted on Facebook and Instagram. Any opinions expressed here are solely those of the author and do not necessarily reflect the opinions of the US Coast Guard or the US Government.

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