Daring Recon Preceded Iwo Invasion

Sea Power, Feb 2005 by Winkler, David F

By February 1945, the Marine Corps had refined the mission of amphibious reconnaissance to a science. Deploying from submarines, PT boats, PBY aircraft or high-speed transports (APDs), Marine reconnaissance teams scouted enemy-held islands to collect valuable intelligence for invasion planners. Campaigns in the Solomons, Gilberts, Marshalls, Marianas, Peleliu and the Palaus all were preceded by insertions of specially trained Marines.

With the Navy's overwhelming victory at the battle of Leyte Gulf and Gen. Douglas MacArthur's ongoing liberation of the Philippines, the United States could now bring the war directly to the Japanese homeland through a strategic bombardment campaign using Army-Air Force B-29 Superfortresses based in the Marianas. Along the flight path were the Volcano Islands, barely habitable land masses fortified by the Japanese Army. The largest of the islands, Iwo Jima, once in American hands, could serve as an emergency landing strip for the B-29s and host P-51 Mustang fighters that could escort the highaltitude raids over Japan.

To secure the island under the Stars and Stripes, the Marine Corps would face some 21,000 Japanese defenders placed in well-hidden fortified positions located throughout the island. However, offshore photography taken by the submarine Spearfish in late 1944, and aerial reconnaissance conducted in weeks leading up to the amphibious assault, failed to unmask the scope and depth of the Japanese defenses.

It would be left to Marines of B Company of the V Amphibious Corps' Amphibious Reconnaissance Battalion to attempt an unveiling of the Japanese emplacements. The tactics employed would hardly be stealthy. Unlike previous missions, the Marines intended to draw enemy fire as a means of revealing gun emplacements.

Two days before D-Day on Iwo Jima, four APDs approached the eastern beaches of the volcanic island and dispatched landing craft loaded with Marine recon teams and Navy Underwater Demolition Team (UDT) personnel. As the landing craft approached the designated drop points in broad daylight, a dozen LCI(G)s - infantry landing craft modified into heavily armed gunboats - stood off to provide supporting gunfire.

From ashore, the advancing landing and covering craft appeared to be the invading force, and the Japanese commander ordered his gun crews to open up. At about 300 yards off the beach, heavily greased Marine and UDT swimmers leapt off the sides of the landing craft to search for underwater obstacles and investigate the beach and surf conditions. Remaining behind in the landing craft, photographers snapped closeups of the beach areas as plumes of water cascaded down from numerous near misses.

Low-flying aircraft, LCI(G)s and offshore combatants provided counter-battery fire to silence several of the Japanese guns. With the Marine swimmers and Navy Frogmen completing their missions, the landing craft sped back to the covering LCI(G)s.

However, for these men the day was only half over. They would be transported to the west side of the island for another swim in the cold Pacific waters while under intensive fire. At the end of the day the swimmers and photographers embarked on several of the offshore transports to brief the landing-force commanders about beach gradients and surf conditions.

With the exception of one mine, there were no offshore obstacles placed to hinder the actual assault. Also, with the intelligence gathered, the pre-H-Hour bombardment was able to knock out some of the Japanese defensive positions.

Protected in underground caves, however, most Japanese defenders survived to battle the Leatherneck invaders who hit the sands of Iwo Jima on Feb. 19.

Eventually, more than 6,000 Marines and Navy Corpsman paid the ultimate price on the island. Twenty-six would receive the Medal of Honor.

While the famous flag-raising on Mount Suribachi occurred only four days after the landing, the struggle for the eight-square mile island lasted another month. Meanwhile, the Marine recon teams and Navy Frogmen were withdrawn to Saipan to prepare for their next mission - Okinawa.

Source: Bruce F. Meyers, Swift, Silent, and Deadly: Marine Amphibious Reconnaissance in thé Pacific, 1942-1945 (Naval Institute Press, 2004).

Dr. David F. Winkler is a historian with the Naval Historical Foundation.