US Navy SEALs: Naval Combat Demolition Unit

From prepping the beaches of Normandy to inventing Hell Week the Naval Combat Demolition Units (NCDUs) produced a dramatic and valuable legacy playing a short; but, essential role in the evolution of the SEAL teams.

Normandy: The deadliest day in Naval Special Warfare’s history

Approaching shore in small rubber boats ladened with explosives the brave men of the the Naval Combat Demolition Units stealthily entered the water during the dark of night preparing the way for follow on landing forces.

On June 6th, 1944 the men of the NCDUs engaged in a historical and bloody battle as they worked to clear a path for the U.S Marines to land at a place called Normandy.

The fighting was dramatic and the losses severe. By the time the assault ended 37 NCDU men were killed and 71 more of them wounded. A casualty rate of over 50% producing the single most deadliest day in Naval Special Warfare history. Their actions were so heroic that the entire unit was recognized by the President of the United States as he awarded them with the Presidential Unit Citation.

Presidential Unit Citation (PUC)

The Presidential Unit Citation is an award given only when an entire unit demonstrates incredible gallantry and determination in accomplishing its mission while under extremely dangerous and difficult conditions.

The units actions must set them apart and propel them above the actions of other units participating in the same campaign.

The degree of collective combat heroism against an armed enemy by an entire unit receiving a PUC would be the equivalent to individual awards such as: Distinguished Service Cross, Air Force Cross or Navy Cross. The men of the Naval Combat Demolition Units “Got some” and helped change history.

The NCDUs who operated at Omaha Beach were the only recipients of a Navy Unit Commendation awarded on that notoriously bloody day called “D-day.”

Merging NCDU and UDTs

The Naval Combat Demolition Units (NCDUs) operated in the Atlantic while the Underwater Demolition Teams were operating in the Pacific. After D-day the NCDUs were engaged in combat once more in Europe during the invasion of Southern France before they were disbanded.

Once operations ceased in Europe the NCDU men who were trained in Fort Pierce were assigned to the Underwater Demolition Teams (UDTs) in the Pacific.

Underwater Demolition Teams shoulder sleeve patch

It was at this moment in time that the volatile, dynamic and secretive mix of heros came together under a single unit completing what we might call the final elemental mix modern day Navy SEALs.

Hell Week – Something for the books

When the NCDUs were absorbed by the UDTs, they brought with them a particularly important evolution called Hell Week. Created by LT Draper Kauffman at Ft. Pierce, this evolution was and still is one of the most demanding evolutions in all of military training. Hell Week is something that every single SEAL on the planet must go through before earning his Trident.

This psychologically demanding evolution is a core element in BUD/s and accounts for a high degree of SEAL trainings legendary attrition rate.

Just a few weeks into BUD/S training, Hell Week’s “Breakout” occurs. Explosions, confusion and instant discomfort ensue to launch 5 ½ sleepless days of brutally cold and uncomfortable training. Fewer than 25% of candidates make it through this evolution.

To the uninitiated Hell Week, stands alone as a pinnacle; but, to those who’ve passed through it, they realize that Hell Week is merely a “kick off” for the rest of training.

There have been countless studies to determine how and why some men make it through Hell Week and many do not. Unfortunately there is only one true way to know if someone has what it takes. They have to go to BUD/S and go through it. There just is no other test.

Hell Week tests a man’s mental toughness. His ability to endure pain, tolerate cold and remain a positive addition to a team while under duress. Ones attitude and ability to thrive under mental and physical stress caused by severe sleep deprivation must be tested.

Overarching any and all descriptors and tests of ones ability to endure pain is one’s ability to persevere at all costs. Hell Week is the ultimate test of ambition.

Constant physical evolutions such as swimming, running with boats bouncing on your head, carrying logs, rolling in the sand and paddling small rubber boats for hours on end can simply be described as painful; but these evolutions aren’t the worst.


For me the worst thing the instructors could do was let us rest. Sitting still to eat or catch a moment of sleep is the single most destructive thing that can be done to a wannabe SEAL. Every minute of rest is met with an hour of pain. Cold, stiff and suffering muscles scream alive in a violent protest as the instructors quietly order you back into action. No excitement to feed from, or fanfare to rally you. Just pain, misery and pure discipline.

Hell Week may seem a bit “extreme,” but SEAL instructors know that the men they allow to pass through will be the very same men they will later be in combat with. This is why, regardless of pressures to make more SEALs, Hell Week has never changed.

To those who make it through Hell Week they are rewarded with a “likely chance of becoming a SEAL,” but, for those who actually make it and become a SEAL they are rewarded with a lifetime of challenges as they realize that things just got started.

As we continue our evolutionary journey it is time bring it all into a single unit. From the hard core Scouts & Raiders to the dynamic Office of Strategic Services Maritime Unit it now all comes together as these men and their legacies transform into the United States Underwater Demolition Teams.