Underwater Demolition Teams were the answer found during World War II to the problem which led to heavy Marine Corps losses in the invasion of Tarawa in the Pacific in 1943, and which faced the Allied Expeditionary Force before the invasion of Normandy in 1944.

Demolition pic

The waves of landing craft carrying troops of the famous Marine Second Division onto the beaches of Tarawa, went aground on a submerged coral reef which had not been revealed by aerial reconnaissance photos about a mile and a half from the beach, thus forcing the troops to wade the long stretch in hip deep water under withering Japanese fire. Losses were thus tragically high before the landing force was even afoot on the Island. It was painfully apparent to staff planners of all services that the success of future amphibious invasion of Japanese held territory would be in jeopardy if there was to be no way of knowing what obstacles, both natural and man-made, lay to seaward of the beach, and if there were no way of clearing such obstacles.

Landing pic

In the meantime the plans were nearing completion for the invasion of the German held Normandy coast by the Allied Expeditionary Force. It was evident that the Germans' initial line of resistance would be mines and underwater obstacles designed to stop the invasion craft. Navy planners therefore conceived the Combat Demolition Units, which would go in with the first wave at Normandy and supplement the Army beach sappers who were faced with the problems of clearing gaps through barbed wire, walls and tank traps.

The first personnel were garnered from the CB's, the Navy Construction Battalion Men, and from the early Navy/Marine Scout and Raider Volunteers who were rugged and capable physically and who had previous swimming experience. They were collected together at Fort Pierce, Florida, in the early summer of 1943. An intensive physical training program was devised, apparently based on the theory that a man is capable of about 10 times as much physical output as is the normal conception. Demolition work was emphasized and non-restricted. Methods were developed for demolishing the type obstacles expected at Normandy. Grueling nighttime problems conducted in the snake and alligator infested swamps of Florida produced a specimen of man who was at home with mud, noise, exhaustion, water, and hostile beings, human or otherwise.

The graduates of the school were organized into small 6 man units, which were called Navy Combat Demolition Units, and a large number were sent to England to join the large invading force in the winter of 1944. No one there knew exactly what they were or what to do with them and it was only after many weeks of being shipped around to various stations and being used merely for watches and guard duty, that they were finally able to settle down for training and invasion rehearsals. Additional men were picked up to swell the units from all sorts of commands, and though previously untrained, these men were fitted into the six man and one officer units.

These men were our original ancestors and no amount of honor bestowed upon them will be excessive; they will always have a place in the rank of history's gallants. The story of the two American beaches at Normandy, Utah and Omaha, has been recorded in detail and is available in many sources. Operations on Utah beach proceeded with relative ease and pretty much as planned, but at the same time Omaha Beach was like the entrance to Hell. The NCD Units accompanied the assault infantry in the boats of the first wave.

The NCDU men did not anticipate any swimming, for the clearance was to be conducted at low tide. They wore impregnated, hooded, canvas fire fighting suits, with field shoes and long stockings, also impregnated. A protective mask covered the bare part of the face; this garb was in anticipation of a spray of mustard gas.The invasion force was wet and seasick after the two day delay on the rough channel. As they neared the beach it was obvious that the preliminary bombardment had been made and lifted on schedule, but the cloudy skies had made it impossible for planes accurately to hit the enemy strong points.

The Germans had reserves available at Omaha and immediately replaced losses at bombarded bunkers. As the boats neared the beach the enemy fire began to fall. Within minutes the water was littered with debris and wrecked craft, and many demolition units were wiped out altogether. An example of the discouraging losses in this H-Hour period was the fact that out of some 20-30 amphibious tanks which were to give supporting fire, only four were seen in action. The Demolition Men proceeded nevertheless to set up charges at their assigned gap spots. There was no shelter on the side sand field, and the men worked as though in a rainstorm, only instead of rain there was shrapnel. The disorganized and misplaced infantry were seeking shelter behind some of the charged obstacles, and were tripping over the detonating cord lines laid out between obstacles. In four places however, they heeded the purple warning flares, and four gateways to France were unveiled with tremendous triumphant explosions. The NCDU losses at Utah were 30%, and at Omaha about 60-70%, giving an over-all average loss of 41% men lost in the assault.

The survivors of this great day were shipped to the Pacific to form the nucleus of the great force being formed. They had not utilized their swim training in Europe but were now to do so. The lessons of Normandy were applied to the amphibious problems of the Pacific Islands, and the basic tactics were developed that still are the basis for operational procedure today. The concept of 6-man NCDU was changed to embrace a structure of Underwater Demolition Teams, consisting of 100 men and 13 officers, two or three of which comprised a unit,and in turn, several of these units comprised squadrons.

Basic training was still conducted at Fort Pierce, Florida, followed by six weeks of advanced training at Maui, Hawaii, which became a staging area for advance operations. The main story of UDT comes out of the Pacific operations which were all done in approximately the same manner. The highly developed methods made UDT operations an effective and well invested weapon and after the Normandy operation until the end of the war, losses were only about 1%. 28 or 29 Teams were now in combat operations; Borneo, Peleliu, Saipan, Tinian, Guam, Lingayen and Leyte Gulfs, Iwo Jima, and in conclusion, Okinawa. At the end of the war there were 34 teams in commission, about 3500 men in all.

They were all combined into 5 tremendous teams designated A, B, C, D, and E for purposes of demobilization. The thousands of fins, coral shoes and face masks were stored in warehouses and the reservists went back home to their civilian occupations and lives; the others were sent to duties on ships and stations as their individual rates called for.

The above history was written in 1960 by W.H. Hamilton, Jr., Commander Underwater Demolition Unit TWO

During WWII there were 32 individual UDT Teams with over 3,000 men total. If you were one of them, your teammates would like to hear from you.

UDT-3 teammates will be happy to know that Clarence "Mullie" "Moe" Mulheren, Jr., USNR, Ret. published a newsletter, THE SEA BREEZE, and coordinated annual reunions of teammates.

Mullie Mulheren

Clarence "Mullie" Mulheren, UDT-3

(Mullie passed away October 27, 2009)

UDT-6 (second Team SIX) formed in 1945teammates are encouraged to contact Bob Broxholme, 1544 11th Avenue, Escondido, California 92029.

UDT 8, 9, and 10 teammates are encouraged to contact William P. (Pete) Katsirubas or Wright Travis for information about the whereabouts of former teammates. Write to William Katsirubas, 7126 Merrimac Drive, McLean, Virginia 22101 or Wright Travis, 1270 Harwood Drive, Libertyville, Illinois 60048

UDT 13 Team historian, Marvin Cooper has written a detailed history, THE MEN FROM FORT PIERCE.

UDT 14 William Harrison's cousin has a website with photos and roster of UDT 14.

UDT-19 teammates are celebrating the 53rd anniversary of the formation of the Team on November 20, 1944, and their motto is "Over the sea for '53". For information contact Phil Koehler, 1341 Kukila Street, Honolulu, Hawaii 96818.


UDT-22 teammates may want to contact Hank Ostendorf for more information about former teammates.

Henry Ostendorf

690 SW 25th St.

Vero Beach, Florida 32962

WWII Underwater Demolition Team Histories

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