VICKSBURG, Miss.— Military weapons, ammunition, equipment, and materials, collectively known as munitions of war, lie at the bottom of rivers, lakes, and oceans across the country. The U.S. Army Corps of Engineers works to safely locate and remove the munitions, preventing aquatic and human environmental hazards. Two U.S. Army Engineer Research and Development Center (ERDC) engineers recently developed a patented technology that could significantly improve how those underwater munitions are detected and recovered.
Taylor Rycroft, a research environmental engineer with ERDC’s Environmental Laboratory (EL), and Griffin Donohue, a technical engineer with the Cold Regions Research and Engineering Laboratory (CRREL), secured a patent for a novel underwater unexploded ordnance (UXO) blast shield apparatus. The device was developed to provide a safe, cost-effective, and environmentally acceptable method for remediating unexploded underwater munitions that are too dangerous to move. The invention specifically addresses the need to mitigate harmful blast pressures and contain toxic detonation byproducts that would otherwise threaten human safety and aquatic life.
The technology reflects Rycroft and Donohue’s attention to detail while developing the product.
“The operation is intended to be safe and efficient,” said Rycroft. “The shield consists of a multi-layered, blast-resistant blanket featuring integrated electromagnets at the edges and an affixed, deflated sacrificial air chamber that we call a bladder. The shield would be lowered and spread directly over the underwater UXO, and the bladder would be inflated with air. The action is then triggered by the intentional detonation of the UXO. The ordnance-facing surface of the air bladder is distressed or pre-ripped, ensuring that it is destroyed immediately during the explosion, allowing the detonation to partially occur in the air before it contacts the blankets.”
Donohue added, “Following the path of least resistance, the blast energy moves through the air bladder and pushes the blanket upward toward the water surface. It is designed to rise in this manner to ensure the electromagnets near the edges of the blanket meet, sealing the ordinance remnants inside. Overall, this design allows the dissipation of energy at the explosion source, the impedance of the shock front, and the redirection of the explosion energy, after which the entire encapsulated package can be safely retrieved from the seafloor.”
Dynamic in its design, the tool’s innovative capabilities cautiously and effectively destroy the weapons, while avoiding harm to their surroundings.
“Our invention is designed to significantly dampen the high-pressure shockwaves and high-velocity fragmentation that could otherwise damage nearby marine infrastructure like pipelines, cables, sub-sediment structures, and historical marine artifacts, or injure personnel executing the blow-in-place mission,” said Rycroft.
“Our design is intended to encapsulate potentially toxic blast remnants, like heavy metals and unburned explosive compounds, and prevent them from spreading into the marine ecosystem. Mitigating the intense underwater pressure waves also reduces the risk of acoustic trauma and mortality to local marine life,” said Donohue.
Whether launched during a past war or studied in military weapons tests, each munition has a unique story of how it landed in the water.
“Underwater munitions ended up in our waterways, lakes, and oceans through a variety of historical military activities,” said Rycroft. “The majority are remnants of past global conflicts, military training exercises, and weapons testing conducted over the last century. Once, it was an accepted practice to dispose of surplus or obsolete munitions by dumping them in the ocean, far away from populated areas.”
“Over time, we have moved closer to these legacy sites as training boundaries have changed, and coastal development has expanded. We now find UXO in coastal waters, inland rivers, and Great Lakes regions, where they present unique management and remediation challenges,” said Donohue.
Innovations such as the blast shield are born when engineers from different ERDC laboratories collaborate to merge perspectives and expertise.
“Working across ERDC labs makes sense because it allows us to combine our respective expertise, ensuring the final design is both structurally sound and environmentally responsible, rather than trying to tackle it from one perspective,” said Rycroft.
“We’ve found that pairing EL and CREEL is highly practical for these types of projects,” said Donohue. “Dealing with underwater UXOs requires that you understand both the physics of a blast and the vulnerabilities of the surrounding ecosystems.”
The two appreciate the opportunity ERDC provides them to create meaningful, affordable, and environmentally safe advanced technology.
“Securing this patent was a rewarding experience for both of us and a meaningful addition to our ongoing research at ERDC,” said Rycroft. “While our patented design aims to be scalable, affordable, and environmentally responsible, the next critical steps are to prototype, test, and refine the technology.”
“This achievement reflects the consistent hard work we put into our projects, and we are proud to have developed a technology that could potentially make a real difference in protecting people, infrastructure, and the environment,” said Donohue. “Our goal is to transition this from a theoretical design into a practical, fielded technology for the DoD, and working toward that milestone is a rewarding challenge.”
Next steps for Rycroft and Donohue include performing analytical modeling, bench testing individual components, and fabricating subscale prototypes for validation in test tanks. Upon approval, the two will test a full-scale prototype in a real-world waterway to assess tactical deployment ability.