Draper L. Kauffman

Combat Demolition Units of the Atlantic Theatre of Operations.

Related Resource: D-Day, the Normandy Invasion, 6 - 25 June 1944

This is a brief history of the demolition units which operated in the Atlantic theatre, their early training, their organization after basic training and advanced training, the difficulties they encountered and the ultimate success in accomplishing their mission. Their missions were unique in that they were assault demolition in nature in contrast to the Pacific operations, which were reconnaissance, and pre-assault demolition. Because they were the first demolition units to operate in any theatre, many problems were met and lessons learned which proved helpful in determining training and policy in later operations. For these and many other reasons it will be necessary to go back to the origin of the units, and briefly follow them through the operations of the Atlantic theatre.

The Naval Combat Demolition Unit started in June of 1943 at Fort Pierce, Florida. The first class arrived and assembled for training the first week in July 1943. The personnel were drawn from three sources, primarily because it was reasonably expected that men from the Construction Battalions, the Bomb Disposal School and the Mine Disposal School would already be familiar with explosives and basic demolitions. The site was chosen because it offered natural swimming beaches and desirable temperatures for year round swimming. Too, it was at a base where demolitions could be carried out and problems could be worked out with the rest of the Amphibious Forces that were already in training at the base.

However, conditions were not as desirable there as they appeared. In the first place, there was no training program set up; no one had any idea as to what the mission might be. No one had the slightest knowledge of what sort of obstacles might be encountered, what pattern they might follow or the best method of destroying them, nor the conditions under which demolition personnel might be called on to work. No provisions had been made for the construction of obstacles, supplying of explosives, housing for the men or training facilities for the unit. Clothing, obstacles, training, program, facilities and explosives were therefore non-existent, yet the men were there and the training did go on. Until steps could be taken to get all of these problems settled, the first class spent from eight to twelve hours per day in physical training and rubber boat drill and primacord knot tying. The heat, sand flies and mosquitoes, food and living conditions were intolerable. From this first class came four of the Naval Combat Demolition Units that were the beginning of the demolition force of the Atlantic Theatre. A Naval Combat Demolition Unit was arbitrarily set as one officer and five men, primarily because it was determined in training that the demolition personnel would work as a rubber boat crew and that the number 6 would be the maximum number of men that could be carried in one boat. Training and facilities at Fort Pierce improved by leaps and bounds and consequently the later units which were sent out were very well trained. These better-trained units will be the ones referred to that joined the units in England prior to the landings. All of the units that operated in the Atlantic Theatre were Fort Pierce-trained.

The first unit sent from Fort Pierce arrived in England in November of 1943, and became attached to Commander Naval Forces Europe until such time as they could figure out who they were, what they were sent for and what their job might be. Then, in December, nine more units were sent over. They, too, found considerable difficulty in getting established and were shipped from one end of England to another without finding anyone who had been delegated to the responsibility of housing and training the demolition units. These arrived at Falmouth Corwall England on the evening of 23 December at 2000 and at 0900 they received word that they had the OOD (Officer of the Day) watch for the next seven days and that the men would assume collateral duties as directed by the executive officer. In substance, the memorandum read as follows:

"1. In addition to your regular duties, you will perform such collateral duties as are assigned you by the executive officer or head of your department.

2. One of your collateral duties is that of Officer of the Day at King's Hotel according to the following schedule: (This listed seven officers for the next seven days, all of whom were Demolition Officers).

3. An additional collateral duty is that of hard master according to plan and schedule to be announced by verbal instructions of Officer in Charge."

The first thought of the demolition units after arrival was to set up an advanced training program. While assuming collateral duties, this was a difficult task. But they did fall into the general work of the base, acting as hard masters and watch standers, while assigning the men to various duties about the base. During their spare time, the units kept busy picking up road obstacles, road blocks, concrete masonry, etc., which had been placed as counter-invasion measures at various points along the coast and hauling them to a small, 200-yard wide beach some eight miles from the Unit's offices. There was carried on an abbreviated training program and a beneficial bit of work in demolition.

For advanced training it was felt that additional training was needed in ship salvage, rocket disposal (i.e., for the unexploded rockets which would be found on the beach), mine recognition, and assault demolition practices of the British. Arrangements were made and officers attended these courses and later taught the men. In January, as a result of attendance at the British equivalent of Naval Combat Demolition Unit known as COXE (Combined Operations Experimental Establishment), much intelligence in the form of pictures and literature pertaining to obstacles already placed on the coast of France was obtained. Of all the obstacles mentioned, the high priority was placed on Element "C" or Belgian Gate. This obstacle is a lattice-faced steel gate propped up on the landward side by steel bracings which are fourteen feet long. The face of the obstacle is 10 feet high and 10 feet wide and the whole structure is of six inch angle iron, one half inch in thickness, welded and bolted together and having a gross weight of about three tons. It could easily be rolled onto the beach at low tide and was strong enough to withstand any surf action. Large numbers had been discovered in back of the dune line along the entire coast of France and it was expected that these might be quickly placed on the beaches at a later date. Inasmuch as this was an entirely new obstacle to the Naval Combat Demolition Units, considerable time had been spent in the determination of the best methods for its destruction.

After considerable difficulty in procurement of a priority for steel, two bays of Element "C" were constructed and placed on the aforesaid abbreviated beach. It was found by experimentation on these that the best method of destruction would be by the use of charges - 16 of them placed at sixteen vital points of the structure - which upon detonation would completely collapse the structure and leave no part of it extending above the surface of the beach more than six inches. This proved very successful in the few tests that were permitted. The greatest difficulty in the process came in the attachment of the charges. From this difficulty came research and design of the Hagensen Pack, a small canvas sack, filled with 2 pounds of C2, which could be fitted and secured to the angle iron regardless of its size or shape by means of a line and V-slot hook of special design. Further and complete experimentation by the group on this obstacle was interrupted when orders from higher authority came and split the units into three separate groups. One group departed for Fowey, Devon England to join the Second Beach Battalion; the second group went to the Sixth Beach Battalion at Swansea, Wales and the third group to the Seventh Beach Battalion at Salcombe, Devon, England. Each of these groups continued training on obstacles of any sort when they were available and when satisfactory beaches could be found. The group at Fowey continued research on the Hagensen pack to determine its sensitivity, shrapnel effect, cutting effect and stability, and investigated manufacturing facilities in the event it would be adopted as a standard explosive for the Naval Combat Demolition Units.

The group with the Sixth Battalion located at Swansea, Wales was able to resurrect road blocks, posts and rails and place them on the long flat beaches and practice dry-runs and time trials which later provided important information for the writing of the operational plan. Meanwhile, eight more Naval Combat Demolition Units arrived from the United States to supplement the units already in training. These were divided among the three groups.

By March the 25th of 1943, the Beach Battalions were ready to go to the marshalling area to await orders to invade. In the absence of official word as to what part the Naval Combat Demolition Units would play and what craft would be assigned if they were to be used, it was found necessary to submit to higher authority a letter stating the capabilities of the enemy to place obstacles on the beach in a comparatively short time and the capabilities of the Naval Combat Demolition Units to destroy them either by daylight assault or night pre-invasion demolition. This letter, together with information of the tremendous increase in obstacles appearing on the beaches of France led to immediate action by higher authority to consolidate the units once more and establish a unified plan of attack.

When it was determined that there would be increasingly larger numbers of obstacles placed, that there was a 25 foot tide change twice a day (which meant working in a tide that rose approximately 1 foot every eight minutes) and that the method of attack would involve assault demolition, it became necessary to reinforce the Naval Combat Demolition Units. Fort Pierce had sent all available units, a total of sixteen Naval Combat Demolitions to England by plane, depleting its supply. Personnel from three Army Combat Engineers were therefore assigned for training by the Naval Combat Demolition Units and all gathered at Appledore, England, where model obstacles were being placed on the beaches for assault and demolition practice. The program for the first time was designed specifically to prepare the men and officers for the landings and emphasized the techniques suggested and agreed upon the operational plans by both the Army and Navy which had been submitted to higher authority for approval. The program was hurriedly organized but was excellently planned. Large areas of beach had obstacles, but there was a definite lack of such obstacles as Element "C", Tetrahedrons and hedgehogs, the three obstacles which were known to exist on the beaches. Those that were placed were made of wood and a very poor substitute, yet the placement of the charges was the important practice that could be had.

The training program at Appledore, England got underway on the 15th of April and ended on the 22nd or 23rd of May. During this time the group maintained the three separate group divisions and worked together; two of these were designated as Force "C" and one as Force "U", the designations of the beaches that were to be assaulted. Each group consisted of 11 gap assault teams. Each team was made up of thirteen men; five Navy Naval Combat Demolition Unit men plus five Army men, plus three seamen sent from a pool in Scotland. Each of these groups was backed up by 26 army men who were to reinforce or support the assault group in later clearance of the beach, the entire group being a gap assault team.

During the early stages of the training program, the officers of each of the Naval Combat Demolition Units were taking care of their units, procuring equipment and organizing the men. There was noticeable need for a commanding officer or a senior officer with the power to make decisions or with authority to procure necessary items or determine policy. When a commanding officer was requested, two Lieutenant Commanders were sent from the United States to take command of the units. Their previous experience in demolition work had been a two-week training course at Fort Pierce, just prior to coming over. There was very little time for them to become familiar with the problems and make the proper decisions, but ever so much was accomplished by their presence in obtaining the latest intelligence data and fitting the units into the invasion plan.

After the training program, all units were removed to Salcombe, Devon, England, including the Army men who were temporarily assigned to the Navy for this operation. At Salcombe, most of the time was spent in preparing 10,000 Hagensen C-2 packs, procuring gear and making final preparations.

For the first time, the intelligence information was coming to the units from naval sources. New obstacles, new patterns of placement, and ever increasing numbers of obstacles were being reported, as was predicted by the Naval Combat Demolition Units. By this time, however, it was too late to change plans or to give special training.

Repeated attempts to procure transportation via LST or the equivalent for personnel and the tremendous amount of explosives at this late date failed to produce results except for the Force "U". All such ships were already assigned. Too, it was impossible to procure the use of LCVP's or the equivalent. The only boats available were the LCT(A)'s or LCT's and those were already assigned to transport troops and equipment. But the teams were assigned as additional load to these and plans began for loading and moving to the French coast. One group, the Force "U" which was to assault UTAH beach did manage to get the use of LCVP's for D-Day.

On 1 June 1944, Group 3, the group which was to attack on UTAH beach, left Salcombe for the marshalling area. On 3 June, the remaining Naval Combat Demolition Units, those who were to attack OMAHA beach, left for Portland, England for embarkation.

The operational plans submitted 31 May 1944, and the one rightfully assumed to be followed, called for the departure from the United Kingdom with one gap assault team per LCT(A). (This is the group of 13 men, 1 officer and 26 additional Army personnel in reserve). Sixteen such gap assault teams went aboard the PRINCESS MAUD, a British liner. Loading of the personnel started at one o'clock the next morning. Each LCT(A) had 52 men and 3 medium tanks aboard. The additional men were the crew personnel for the tanks that were being carried and, according to the operational plan, were to land and assist the demolition units by giving support and removing any obstacles not cleared in the initial assault. On 5 June, the officers of the OMAHA force were picked up from the LCT(A)'s and taken aboard the U.S.S. ANCON, the flagship, and there received their first and final briefing. Although this was almost entirely unsatisfactory it did give the men a picture of what was going to happen. The Army personnel aboard the LCT(A)'s were able to give some additional information on intelligence data because they had been in a marshalling area for weeks and were presented with all the available information for perusal and study. Prior to departure and after the officers returned from the ANCON, an LCM was assigned to each LCT(A) and was to be towed to the transport area where the Demolition gap team would disembark onto them and proceed to the beach.

(Continued in Part 2)