SEAL History: Origins of Naval Special Warfare-WWII

The origins of Navy SEALs actually began with specially organized maritime commando units during World War II, where legacy capabilities were adopted and remain embodied in today’s SEAL Teams.

Amphibious Training Base, Little Creek, VA

During preparation for amphibious warfare operations in the Chesapeake Bay, two special-mission units were formed almost simultaneously at the Amphibious Training Base (ATB), Little Creek, Norfolk, VA in late August 1942. Each was to perform specific missions in Operation TORCH – the allied invasion of North Africa the following November; however, there is no evidence that either knew about the other or their assigned tasks during this period.

Amphibious Scouts and Raiders (S&R)

Amphibious Scouts and Raiders (Joint) were created specifically to reconnoiter prospective landing beaches and to lead assault forces to the correct beaches under cover of darkness. The unit was led by U.S. Army 1st Lieutenant Lloyd Peddicord as commanding officer, and Navy Ensign John Bell as executive officer. Navy chief petty officers and sailors came from the boat pool at ATB, Solomons, Maryland and Army Raider personnel came from the 3rd and 9th Infantry Divisions. They trained at Little Creek until embarking for the North Africa campaign the following November. Operation TORCH was launched in November 1942 off the Atlantic coast of French Morocco in North Africa. One mission, under Army 1st Lieutenant Willard G. Duckworth, involved the launching of kayaks from the submarine USS Barb (SS-220). This was the first U.S. submarine hosted operation of World War II involving specially trained reconnaissance personnel. Their mission was to infiltrate to a location off the Jette Principal at Safi, Morocco under cover of darkness to safely guide the destroyers USS Cole (DD-155) and USS Bernadou (DD-153) to near-shore gunnery positions.

S&R men also conducted pre-assault operations at Normandy several weeks before D-Day, 6 June 1944, and at the invasion of Southern France later that August. After that the need for Scout and Raider capabilities in Europe ended; no other amphibious operations were envisioned in that theater. Many of the men returned to Fort Pierce to serve as instructors at the Scouts and Raiders School. Army personnel were returned to their parent units, and many navy men were reassigned to sea duty or given the opportunity to join the Pacific units.

S&R teams performed a variety of actions and activities to guide ships and small craft throughout Operation TORCH, often under withering fire. They performed so admirably that all Scout boat officers were awarded the Navy Cross Medal. The Scout and Raider school was relocated to ATB, Fort Pierce, FL in February 1943, where, in the following July, it became an all Navy school.

S&R operations in the Mediterranean and Pacific Theaters also provided the framework for legacy capabilities now accomplished by today’s NSW Special Warfare Combat-Craft Crewmen (SWCC) operators.

Special Mission Naval Demolition Unit

Also in August 1942 at ATB, Little Creek, a specialized naval demolition team was formed with two officers and 17 enlisted men. They were led by Lieutenant Mark Starkweather (senior in command) and Lieutenant James Darroch. All were trained Navy salvage divers brought in from Hawaii. Their crash course included: demolitions, commando tactics, cable cutting, and rubber boat training. Their singular mission during Operation TORCH was to remove the cabled boom blocking the Wadi Sebou River, which spilled into the Atlantic Ocean along the west coast of French Morocco. Removal of this boom would allow USS Dallas (DD-199) to proceed up the river and train her guns on the Port Lyautey airdrome in preparation for attack by Army Rangers that were previously embarked aboard Dallas.

The operation was launched just before H-Hour on 8 November 1942. The men operated at night from an open Higgins boat in very heavy seas and under direct enemy machine-gun fire. Several of the men were badly injured in the rough seas, and the first attempt was aborted. During a second attempt on the night of 9 November, they accomplished their task. Their mission was so demanding and critical to the success of the invasion that every demolition man in the operation was awarded the Navy Cross Medal. This special-mission naval demolition unit was disbanded once the men returned from Africa.

The Naval Demolition Project

On 6 May 1943, the “Naval Demolition Project” was directed by the Chief of Naval Operations to “to meet a present and urgent requirement.” The CNO’s directive outlined a two-phase project.

The first phase began with a letter to the Chief of the Bureau of Yards and Docks directing dispatch of eight officers and 30 enlisted men for duty with the Operational Naval Demolition Unit and Naval Demolition Unit Number No. 1, which was to be established at the ATB, Solomons, Maryland. Commander John C. Daniel was selected as Officer in Charge. Six officers and 18 enlisted men reported for training at Solomons on 14 May, and all came from the Seabee training camp at Camp Peary (Williamsburg), Virginia.

Led by Navy Lieutenant Fred Wise, these men were given a four-week course of instruction and sent immediately to participate in Operation HUSKEY, the Allied invasion of Sicily, which occurred during the following July and August.

CDR Daniel submitted a letter report about this new capability on 27 May 1943. His report, which proposed an outline for the second phase, recommended an organization, outlined a detailed core training syllabus, and recommended a list of equipment need to supply an operational combat demolition unit. He further recommended that the training program be detached from Maryland and relocated to ATB, Fort Pierce, Florida to take advantage of good weather for year-round training.

Naval Combat Demolition Units (NCDUs)

On 6 June 1943, the Naval Combat Demolition Unit (NCDU) training school was established at Ft. Pierce, Florida and organized by LCDR Draper Kauffman. He assembled volunteers from the Bomb and Mine Disposal School, Washington, DC (which he organized), and the Civil Engineering Corps and Naval Construction Corps (Seabees) School at Camp Peary near Williamsburg, Virginia to fill the first training classes.

LCDR Kauffman is given credit for instituting the infamous “Hell Week,” a period of intense instruction that remains a fundamental component in modern-day Basic Underwater Demolition/SEAL (BUD/S) training program. By the end of Ft. Pierce training there was an overall attrition rate of 65-75%, much like it remains today in BUD/S.

In some accountings, LCDR Kauffman has also been given credit for the establishment of the Underwater Demolition Teams (UDTs) in the Pacific during WWII, but this is not factual. The UDTs were formed in December 1943, while LCDR Kauffman was still at Fort Pierce. He left his training position at Fort Pierce in April 1944 to become commanding officer of UDT-5 in Maui, Territory of Hawaii.

Each NCDU was comprised of one officer and five enlisted sailors to make up a single boat crew. The first NCDU Class graduated in September 1943; after several months of arduous training with primary emphasis on demolition of submerged beach obstacles (submerged in a surf zone). Seven units were dispersed to the Third and Fifth Fleets in the Pacific, three units went to the Eighth Fleet in the Mediterranean, and only one unit went to England. By April 1944, however, a total of 34 NCDUs had collected in England in preparation for Operation OVERLORD, the amphibious landing at Normandy.

D-Day – The Bloody Sands of Normandy

For the assault at Normandy, each six-man NDCU was augmented with three U.S. Navy seamen brought in from Scotland to assist in handling demolitions. The resulting nine-man NCDUs were later integrated with U.S. Army combat engineers to form 13-man gap assault teams.

During the assault on June 6, 1944 NCDU men suffered 37 killed and 71 wounded, a casualty rate of 52%; making D-Day the bloodiest single day in the history of Naval Special Warfare; although not one NCDU man was lost to improper handling of explosives.

The NCDUs at Omaha Beach were awarded the Presidential Unit Citation; one of only three presented for military actions at Normandy. The men at Utah Beach were recipients of the only Navy Unit Commendation awarded for actions on that awful day.

The Invasion of Southern France

NCDU men were engaged in combat only once more in Europe, and this was during the invasion of Southern France in August 1944. First code-named ANVIL and later DRAGOON, several of the NCDUs from Utah Beach were augmented with new units from Fort Pierce to participate in the last amphibious assault of the war in Europe. Once operations ceased in Europe, all Fort Pierce trained men were sent to the Pacific and assigned to Underwater Demolition Teams.

NCDU men contributed greatly to the war in Europe, and their efforts are often overshadowed by the Pacific UDTs. Indeed, in some historical accountings, it has been written that UDTs performed work at Normandy and Southern France, however, during WWII the UDTs operated only in the Pacific.

Moreover, NCDU men have often been referred to as “frogmen” by some authors and historians; however, in those early days swimming was only a test and a method of physical training. The men wore full combat dress, and were taught to operate stealthily at night and during pre-dawn hours by wading in surf and carrying explosives to obstacles from rubber boats.

MacArthur’s Frogmen

Many of the early Fort Pierce-trained NCDUs were deployed to the Pacific Theater of Operations. NCDU-1 went to Alaska in August 1943 to participate in the Aleutian Islands Campaign– before actually finishing their formal training class. These operations were a struggle over the Aleutian Islands, which were then a part of the Alaska Territory. The NCDU men were never engaged, since the Japanese had already departed the islands. They were subsequently transferred to Waimanalo, Territory of Hawaii to be embedded with the provisional UDT-1.

NCDU-2, NCDU-3, NCDU-19, NCDU-20, NCDU-21, and NCDU-24 went to the Southwest Pacific, and remained together for the war’s duration (the only NCDUs never to be subsumed into a UDT). LTjg Frank Kaine was the leader of this group, which later became known as “MacArthur’s Frogmen.”

NCDU-4 and NCDU- 5 also went to the Southwest Pacific. They were the first Fort Pierce men to actually be committed to battle in the Pacific, when they operated with the 4th U.S. Marines at Green Island and Emirau Island in the Bismarck Archipelago of the South Pacific at New Guinea. These men were eventually returned to Hawaii and assigned duty with the UDTs.

Special Services Unit ONE (SSU-1)

A second and lesser-known group of Scouts and Raiders, code-named Special Services Unit One (SSU-1), was established in the Pacific on July 13, 1943. SSU-1 was a joint and combined international force, with personnel from Australia and the U.S. Army, Navy, and Marine Corps. They were trained in martial arts, hand to hand combat, map making, rubber-craft operations, jungle survival training, Pidgin English, underwater coral formations, and sea-creatures recognition.

Their operations, actions, and activities began in September 1943 at Finschafen, New Guinea, where they conducted near-shore and in-land reconnaissance operations; often with indigenous personnel. Similar operations were carried out at Gasmata, Arawe, Cape Gloucester, and the eastern and southern coasts of New Britain; all without loss of personnel.

The focus of this organization was much different than their Atlantic counterparts, who conducted pre-assault reconnaissance and guided assault waves ashore. SSU-1 collected intelligence and trained and operated with indigenous personnel in the conduct of guerrilla-warfare missions. They were later designated the 7th Amphibious Scouts and organized under staff intelligence sections; somewhat along the lines of their Atlantic counterparts.

Sino-American Cooperative Organization (SACO)

Many Scout and Raider personnel returning from Europe were given special assignment with the U.S. Naval Group in China, headed by Captain (later Admiral) Milton “Mary” Miles. He and his Chinese counterpart set up the Sino-American Cooperative Organization (SACO) to train, equip, and direct guerrilla forces against the Japanese occupation of China. To help bolster the work of SACO, the Chief of Naval Operations Admiral Ernest J. King ordered 120 officers and 900 men trained for ”Amphibious Roger” at the Scout and Raider School at Ft. Pierce.

Amphibious Roger was a cover name for Navy personnel being groomed to support SACO and conduct raids on the Yangtze River. Many of these men never made it to China because the war ended. Those who did were used to train Chinese guerrilla forces and conduct reconnaissance operations with them until the end of the war. They were also tasked to locate and survey prospective landing beaches for a potential invasion of the Chinese mainland, report on Japanese ship movement, and provide weather reports to the fleet. They were later glamorized as the “Rice Paddy Navy.”

Underwater Demolition Teams (UDTs)

On 22 November 1943, during 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.

A memorial to the founding of the UDT is being built Bellows Air Force Station near the original Amphibious Training Base (ATB) Waimanalo.

Invasion of Japan

During June 1945, arrangements were being made to send the existing 28 UDTs to ATB Oceanside, California for a month-long period of cold-water training in preparation for the Japan invasion. Training was to begin on 15 August 1945. During this period, a new command organization was authorized, when the collection of teams at Oceanside was designated a UDT Flotilla, with two subordinate UDT Squadrons. Captain (later Admiral) Robert H. Rodgers served in the dual capacity of Commander, Underwater Demolition Flotilla and Commander, Underwater Demolition Teams. Under him were Underwater Demolition Squadrons ONE and TWO, each with a command staff. USS Hollis (APD-66) served as command ship for the Flotilla, and USS Blessman (APD-48) and USS Laning (APD-55) were designated as Squadron flagships. Even today, this remains the largest single Naval Special Warfare task organization gathered under one commander for combat operations.

Training at Oceanside was abruptly curtailed after President Harry S. Truman ordered the use of nuclear weapons at Hiroshima, Japan on 6 August 1945 and at Nagasaki, Japan on 9 August. With a Japanese peace offer on 10 August, 20 of the UDTs in training on the west coast were alerted, and with the Japanese surrender on 14 August, they were ordered to proceed to the forward area for occupation duties.

Post-War UDTs

Thirty UDTs were organized during World War II. UDT-1 and UDT-2 were disbanded almost as quickly as they were formed, there were at most 28 teams at any one time. All teams were trained at Fort Pierce except UDT-1 and UDT-2 (the provisional teams), and UDT-14, UDT-16, and UDT-17, which were made up largely of fleet volunteers, all trained in Hawaii.

Four 50-man teams were established during the post-war period. UDT-1 and UDT-3 were home ported at ATB, Coronado, CA, and UDT-2 and UDT-4 were sent to ATB, Little Creek, Norfolk, VA. All were organized under Amphibious Forces Pacific and Atlantic respectively. These were the only WWII maritime commando units to survive doctrinally after the war and thus, provided a direct lineage to the modern-day SEAL Teams.

Office of Strategic Services Maritime Unit

Undoubtedly the most influential World War II legacy unit that would eventually affect the capabilities of the Underwater Demolition Teams, and subsequently the U.S. Navy SEAL Teams, was a joint-service maritime component of the Office of Strategic Services (OSS). Many of its capabilities were later adopted by the post-war UDTs, and many of the same capabilities can be found in today’s SEAL Teams.

On January 20, 1943, a Maritime Section was established within the Special Operations Branch of OSS, with responsibility for planning covert infiltration operations from the sea. On June 10, 1943 the Special Operations Branch was reorganized and the Maritime Unit (MU) was established with branch status. Its responsibilities included planning and coordinating the clandestine infiltration of agents, supplying resistance groups, engaging in maritime sabotage, and developing special equipment for operations from the sea.

OSS MU pioneered U.S. capabilities in maritime sabotage through use of special-boat infiltration techniques and tactical combat diving using flexible swim fins and facemasks, closed-circuit diving equipment, submersible vehicles, and limpet mines. These capabilities were adopted by the UDTs in 1947, and became the hallmark of SEALs lasting through the modern day. OSS MU operations in the Mediterranean and China-Burma-India Theaters also provided the framework for legacy capabilities now accomplished by NSW SWCC operators and resident in the NSW Special Boat Teams.


“More Than Scuttlebutt – The U.S. Navy Demolition Men in WWII,” © 2009, Sue Ann Dunford and James Douglas O’Dell, printed in the United States (

“Spearheading D-Day: American Special Units in Normandy,” by Jonathan Gawne, 2011, Histoire and Collections Publisher

“Hidden Heroes: Amphibious Scouts of Special Services Unit #1,” June 2007, by Teresa “Pat” Staudt and Hank Staudt. A self-published research project provided to the Navy Historical Society

Commander in Chief, United States Fleet, to Vice Chief of Naval Operations: Subject: Naval Demolition Units Project, 6 May 1943, Serial 01398 (National Archives, Textual Reference Division, Military Reference Branch, Suitland, Md.)

Vice Chief of Naval Operations to Chief of the Bureau of Yards and Docks: Subject: Personnel for Naval Demolition Units, 15 May 1943, Serial 01911223 (National Archives, Textual Reference Division, Military Reference Branch, Suitland, Md.)

Officer in Charge of Naval Demolition Unit to COMAMPHIBFORLANT: Subject: Recommendations for Naval Demolition Units, organization, training, and equipping of permanent units, 27 May 1943 (National Archives, Textual Reference Division, Military Reference Branch, Suitland, Md.)

Commander in Chief, U.S. Pacific Fleet, History of the Amphibious Forces, U.S. Pacific Fleet, “History of Naval Combat Demolition Training and Experimental Base, Kihei, Maui, T.H.,” Section 150C, 166 (The Naval History and Historical Command, Washington, D.C.)

“Scouts and Raiders – The Navy’s First Special Warfare Commandos,” © 1993 by John B. Dwyer, Praeger Publishers, Westport, CT

“The Naked Warriors,” © 1956 by Commander Francis Douglas Fane, Appleton-Century-Crofts, Inc. New York

Commandos from the Sea: The History of Amphibious Special Warfare in World War II and the Korean War,” © 1998 by John B. Dwyer, Paladin Press

“A Different Kind of War: The little-known story of the combined guerrilla forces created in China by the U.S. Navy and the Chinese during World War II, © 1967 by Milton E. Miles, Doubleday & Company, Inc.

“SACO – The Rice Paddy Navy,” © 1950 by Roy Olin Stratton, Palmer Publishing Company, Pleasantville, N.Y.

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