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UDT and The Navy Seals

Posted by Momentum Watches - April, 23

Since we launched the new Momentum version of the original Chronosport Sea Quartz 30, we have been inundated with requests for a remake of the original UDT analog-digital dive watch. As we prepare for the launch of the new UDT Solar, we thought it would be nice to share a little information about the UDT and Navy SEALS.

Since we launched the new Momentum version of the original Chronosport Sea Quartz 30, we have been inundated with requests for a remake of the original UDT analog-digital dive watch. As we prepare for the launch of the new UDT Solar, we thought it would be nice to share a little information about the UDT and Navy SEALS.

Since Operation Neptune’s Spear, the raid that killed Osama bin Laden in 2011, the American public and the world at large is quite familiar with the U.S. Navy’s SEAL teams. An avalanche of books, television shows, podcasts, and even films—some starring active-duty Navy SEALs and sanctioned by the Navy—have propelled the SEAL community to the very top of the public consciousness.

The Navy SEAL Teams are the U.S. Special Operations Command’s (SOCOM) go-to choice for maritime special operations. They specialize in direct action, special reconnaissance, and underwater unconventional warfare and can infiltrate and operate from the sea, air, and land.

But despite the widespread popularity of the SEALs, not many know about the humble beginnings of the community during the early, bleak years of World War II. Then, there were no Navy SEALs but rather the frogmen of America’s Underwater Demolition Teams (UDTs).

When the Japanese attacks on Pearl Harbor and the Pacific pulled America into the chaos of World War II, the U.S. Navy and Marine Corps didn’t have a dedicated beach-clearing and reconnaissance unit 

A lot of things have to happen before an amphibious landing can take place. The tides, underwater obstacles, and density of the sand were just some of the environmental aspects that commanders needed intelligence on to plan amphibious operations. Could the sand on the beaches of Saipan hold American tanks, or would they get bogged down? Were the beaches of Okinawa rigged with explosives or obstacles to prevent the amphibious vehicles from approaching? A Marine or Soldier laden with gear could easily drown within meters from the beach. So, understanding the operational environment was critical.


Battle of Tarawa.

The need for such a capability became increasingly evident as the Navy and Marines began the island-hopping campaign across the Pacific. But it was the Battle of Tarawa in 1943 that bloodily opened the eyes of the Pentagon.

Non-existent reconnaissance of the beaches resulted in the landing Marines getting pinned down on the beaches. Landing craft couldn’t approach the beachhead, and Marines had to wade through both seawater and murderous Japanese fire as they went. In the three days that the battle lasted, over 1,000 Marines were killed and more than 2,000 were wounded in one of the costliest actions in the Corps’ history.

The Pentagon got the message and ordered the establishment of several underwater special operations units, such as the Underwater Demolition Teams, Amphibious Scouts and Raiders, the Special Mission Naval Demolition Unit, the Underwater Demolition Project, and the Naval Combat Demolition Units. Although different, despite very similar names, these units shared many skill and mission sets, and the fact that there were so many of them has more to do with a less organized, war-time military than with competing goals between the units.


Rear Admiral James L. Kauffman, presents Lieutenant Commander Draper L. Kauffman, a gold star in lieu of a second Navy Cross for heroism under fire (U.S. Navy History and Heritage Command). First Platoon of UDT.

When Kauffman got the order to establish a UDT school, he went across the fleet in search of volunteers for the new specialty. Several officers from Reserve Officer Training Programs (ROTC) raised their hand, as did many Seabees, or members of the Naval construction forces who were accustomed to operating in active combat environments.

Then the training began. Kauffman envisioned an elite special operations unit and the training reflected that vision. Small-boat operations, swimming, explosives, small-arms, and hydrographic charting were some of the topics the volunteers focused on, with physical training being a staple throughout the course. Top physical condition was a must, given the extremely arduous missions that the frogmen would be called upon to complete.


The training regime culminated with an evolution that today is known as “Hell Week.” It was a non-stop 7-day event (nowadays, Hell Week is usually five-and-a-half days) full of physical activities meant to push candidates to their absolute limits to see who can still perform when tired and cold beyond comprehension. Only 25% to 35% of those who began training made it through to the end.

The Navy soon deployed these units for the first time in large numbers in Europe, and shortly after in the Pacific.


The Underwater Demolition Teams—the ones who survived after the war and the closest direct ancestors of the Navy SEAL Teams—were much larger than the previously mentioned units. With approximately 15 officers and 70 enlisted, each UDT was closer to a company-strong unit than the other, smaller Naval special operations units.

The UDTs first saw action in the Marshall Islands in 1944, followed by the invasion of the Mariana Islands (Saipan, Tinian, Guam) in June of the same year. The UDT’s frogmen conducted hydrographic reconnaissance and cleared the shallows and beaches, enabling the successful capturing of the islands. Their next and biggest challenge came during the Battle of Okinawa, where close to 1,000 UDT frogmen worked in the frigid Pacific waters to ensure that the Marines could land safely. After the fall of Iwo Jima and the atomic bombs in Hiroshima and Nagasaki forced Japan to surrender, UDT frogmen were the first Americans to reach the Japanese home islands and receive the surrender of a Japanese unit.


By the end of the war, there were 34 Underwater Demolition Teams, with 21 of them seeing combat. The end of the world conflict brought a great downsize to the U.S. military, with the Underwater Demolition Teams suffering cuts alongside the rest of the force. Although they had proven their worth, there was no one else to fight—the Cold War wouldn’t begin for some years. But Korea loomed in the distance, and the Underwater Demolition Teams would once more be called to do extraordinary feats.

Shortly after he took office, President John F. Kennedy directed that all service components develop an expanded capacity for non-nuclear warfare. Specifically, he told Congress, “I am directing the Secretary of Defense to expand rapidly and substantially the orientation of existing forces for the conduct of non-nuclear war, paramilitary operations, and sub-limited or unconventional wars.” As a result of that directive, two new Navy teams were commissioned in January 1962: SEAL Team One (West Coast) and SEAL Team Two (East Coast). The new teams took up residence at the naval amphibious bases in Coronado, California, and Little Creek, Virginia, respectively.

The acronym SEAL came from a contraction of “sea-air-land” and was first used by the Navy’s Unconventional Activities Committee, whose recommendations led to the formation of the SEALs. The teams were drawn from underwater demolition team (UDT) veterans, but with mission responsibilities that included airborne and land operations as well as traditional maritime activities. New teams began to train for direct action and reconnaissance missions on land, coming from or under the sea or from the air.

Early on, basic UDT training was the same as basic SEAL training, hence the name, Basic UDT/SEAL training, which was shortened to BUD/S training. The rigorous conditioning and the notorious Hell Week remained much the same as it had been during the time of UDT pioneer Draper Kauffman and the Navy frogmen of World War II.

1984: Conversion of the UDTs

While the SEALs endured continuous deployment rotations to Vietnam, the UDTs continued to evolve underwater, focusing much of their time and energy on combat-swimmer operations and the complex business of operating wet mini-submersibles from parent nuclear submarines. Those operations became so specialized and all-encompassing that in 1984, two of the four remaining UDTs were converted to SEAL teams and the other two became SEAL delivery-vehicle teams or SDV Teams. The new SDV teams were manned by fully mission-capable SEALs, but they specialized in underwater and over-the-beach operations.


With the conversion of the UDTs and the growth of the SEALs, the current disposition of SEAL/SDV teams is as follows: SEAL Teams One, Three, Five, and Seven are based in Coronado, California. SEAL Teams Two, Four, Eight, and Ten are in the Norfolk, Virginia, area. SDV Team One is in Hawaii. There are two reserve SEAL teams, Seventeen and Eighteen. There currently is no SEAL Team Six.

Since 2000, SEALs have deployed with their own integral command, control, and support organizations—the SEAL squadron. A SEAL squadron has three to four standalone SEAL task units, each with two SEAL platoons and an integrated combat-support package. The task units, with their internal intelligence and targeting capability, have dramatically enhanced SEAL and Naval Special Warfare capabilities in the operational theaters. The deployment of SEALs with this expanded staffing and combat-support capability in self-contained squadrons was put in place just in time for the heavy combat rotations that followed 9/11.

When the original UDT (Universal Dive Timer) watch was launched in the early 1980’s, analog quartz watches were still a new technology.  Ana-digi quartz movements offered the accuracy, reliability, and affordability of quartz, with simple analog legibility and more complex functions (like Day & Date, Chronograph/Stopwatch, Dual Time/GMT, Alarm & Hourly Chime) provided via the digital display. Through the 1980’s and early 90’s, it became a go-to watch for many military units; it was famously also worn by  Sylvester Stallone in RAMBO II, Rick Simon on Simon & Simon, and many others.


The new MOMENTUM UDT Solar offers the style and simple design of the original Chronosport version, with valuable enhancements, including a larger digital display, a scratchproof sapphire crystal, an ultra-durable ceramic bezel, reliable screw-lock pushbuttons, an improved 200M/660FT waterproof rating, SuperLumiNova luminous for easy reading at night, etc.. Deliveries will begin in September of 2024.


Advertisement from Skin Diver Magazine for the first UDT dive watch, which ran in 1981/82. The original version had a 4-digit LCD display down by 6 o’clock, with the movement supplied by ETA. As the ETA movement had a few technical issues and limited functions, the UDT II soon replaced it. This used a 6-digit Epson movement.

Chronosport and Momentum archives
Dick Couch, US Naval Institute.
Stavros Atlamazoglou, Sandboxx News