Navy Combat Demolition Units Prepared the Way for D-Day

Sea Power, May 2004 by Winkler, David F

Under Fire, Teams Cleared Obstacles that Allowed Invasion Forces to Hit the Beaches

The Navy had an obvious role in the June 6, 1944, D-Day landings 60 years ago in Normandy, France, by performing the pre-invasion shore bombardment, follow-on gunfire support, plus transporting and landing many of the Army troops who stormed ashore. Less known are the heroics of Navy Combat Demolition Units (NCDUs) that preceded the invasion force to disable obstacles planted along the French coastline.

By late 1943, 10 NCDUs had arrived in England from Fort Pierce, FIa., to meet with their British counterparts and train for an anticipated future mission. In February 1944, the units split and joined with the second, Sixth and Seventh Beach Battalions, the organizations set up to coordinate and facilitate the Army landings. At this time, eight additional six-man units arrived from the United States to be split among the Beach Battalions.

As the weather warmed, it became increasingly apparent that the NCDUs would be needed. Reconnaissance of the proposed landing sites at Normandy revealed the Germans were improving their fortifications by installing a complex series of obstacles along the beachfronts.

As Hitler's "Atlantic Wall" became more formidable, additional Navy combat demolition experts arrived. The subsequent arrival of some Army Combat Engineers enabled each of the NCDUs to double in size.

In April, the young officers leading the Navy units and their Army counterparts were briefed by higher-echelon officers about a hypothetical long, wide, gradual sloping sand beach with a 25-foot tide change.

On that beach, and extending into the surf, they could expect minefields and a variety a devilishly designed obstacles placed to block and cripple landing craft.

To clear the beach, the invasion planners envisioned an aerial and naval bombardment sweeping the coastline. Then the initial wave of infantry, supported by specially designed amphibious tanks, would land at low tide after dawn and rush up to secure the beaches.

Following in their wake, the NCDUs would land with a mission to blow a 50-yard gap in the German obstacles, and place markers so landing craft coming in later that morning at high tide would have a straight, unobstructed path leading to the beach.

For the Americans, the hypothetical beaches were "Utah" and "Omaha." At 0630, H-Hour, on the morning of June 6, 1944, 11 NCDUs came in with the 8th Infantry Regiment at Utah. With the Army securing the beach, the Navy demolition men went to work and quickly blew eight 50-yard gaps and had enough time to expand one gap to 700 yards. This allowed follow-on waves of troops to pour ashore and quickly secure a substantial beachhead by midday.

Four sailors were killed during the mission and 11 others were wounded. Because of their efficient work, these units received a Navy Unit Commendation.

At Omaha, the Germans were better entrenched and had built a more robust network of obstacles. It didn't bode well for the 16 incoming NCDUs that the pre-invasion air and sea bombardments mostly missed their marks. Also, choppy seas swamped many of the amphibious tanks, depriving the invaders of needed close-in firepower.

As a result, the invaders were savaged by heavy artillery, mortar and machine gun fire that ripped into the NCDU landing craft and followed the brave sailors as they struggled to demolish the obstacles.

Hostile action accounted for 31 killed and 60 wounded, a casualty rate of more than 50 percent. Yet by the time of the first high tide, the units had created five gaps for follow-on waves to use to get to the tenuous beachhead. When the tide receded that afternoon, the surviving demolition experts plunged back into the surf to create seven more gaps, some as wide as 150 yards.

Through those gaps poured the reinforcements needed to hold off any counterattacks and take the fight inland. Seven sailors earned the Navy Cross for their work that day.

For their heroic actions, the Omaha NCDUs received a Presidential Unit Citation.

Sources: Cmdr. Francis D. Fane, USNR (Ret.) and Don Moore, The Naked Warriors: The Story of the U.S. Navy's Frogmen (Naval Institute Press, J995); Jonathan Gawne, Spearheading D-Day: American Special Units in Normandy (Histoire and Collections, 1998). Assistance also was provided by Mark Wertheimer of the Naval Historical Center.

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