Naval Research Laboratory Protects Naval Assets: Land, Sea and Air

Naval Research Laboratory Protects Naval Assets: Land, Sea and Air

by Emily Winget

25 September 2025 The relentless assault of salt-laden sea spray generated by coastal wave action poses a significant and persistent threat to the integrity of Department of Defense assets near and far from shorelines.This corrosive environment accelerates the deterioration of critical military and naval resources, challenging their lifespan.

"Ensuring the readiness of our naval assets is paramount to the Navy's mission, and understanding the insidious threat of corrosion, even far from the waterline, is a critical component of that readiness," said Capt. Jesse Black, U.S. Naval Research Laboratory's (NRL) commanding officer. "By advancing our understanding of corrosion, we can develop innovative solutions to protect our ships and equipment, ultimately saving valuable time for our sailors and safeguarding our vital assets."



Alex Johnson is a National Research Council postdoctoral fellow with NRL's Chemistry Division Center for Corrosion Science and Engineering. He studies the impact of corrosion from saltwater aerosols on naval assets to better understand how breaking waves produce a mist that can cause costly damage.

"This research is crucial for understanding the potential for corrosion on naval ships, aircraft and equipment, even those located at a distance from the water," Johnson said. "By quantifying the distribution and deposition of salt aerosols, we can better assess the corrosion risk associated with different locations and environments."

Johnson is conducting research at the NRL Laboratory for Autonomous Systems Research Littoral Bay Wave Pool to simulate ocean conditions and learn how saltwater aerosols are generated and transported by waves, bubble bursting and interactions between the land-sea interface.

Johnson strategically placed 3D-printed, specially designed airfoils above the wave pool, subjecting them to typical environmental conditions found along a shoreline. He aims to determine how far and how much salt spray can travel to learn how the spray can impact naval assets located away from the immediate shoreline.

"We have observed that there is a zone of enhanced corrosion proximate to the shoreline. The corrosivity is worse right at the surf zone and then rapidly decreases over hundreds of meters," said Raymond Santucci, materials engineer in NRL's Corrosion Science Section. "Over longer distances, the corrosivity is lesser and decreases more gradually but has an impact much further inland. Whether we are conducting field testing, or DoD is deploying assets at installations, the exact distance matters when you are close to the coast."

Distance matters to both surface and subsurface vessels, as well as to naval aircraft that are exposed to sea salt aerosols during flight within the marine boundary layer-the lowest part of the atmosphere directly impacted by the ocean-and while stationed on flight decks or at land-based installations.



"The design and sustainment of DoD assets is improved if the corrosion risk of the operating environment is better characterized," Santucci said.

Currently, maintenance protocols (i.e., rinsing, washing, covering, inspection and repairs) are determined by factors such as the severity of the deployment location, the flight altitude above sea water and proximity to the ocean. The existing protocols do not consider corrosion caused by traveling sea salt aerosols. Time, manpower, materials and money can be better allocated if preventative and corrective maintenance is calibrated correctly for the severity of the location. This is where Johnson's research comes in.

"The results of this research will lead to better corrosion modeling and the ability to tailor corrosion maintenance based on specific service conditions, thereby optimizing resource usage," Santucci said.

In Johnson's experiment, the Littoral Bay was equipped with wave actuators for controlled wave crashing to generate sea spray. The pool was filled with "instant ocean" to simulate ocean water, and a scaffolding structure was used to mount equipment for a five-day exposure.

"The goal of the experiment is to characterize dry deposition, airborne concentration and particle mass size ranges of sea spray aerosol with height in a controlled setting that mimics the land-sea interface," Johnson said.

To further enhance the realism of the study, Johnson plans to introduce a slope to the wave pool to create an artificial shoreline. Testing with the sloped configuration is scheduled to commence in summer 2026.

"Our corrosion data varies wildly for locations close to a shoreline. We hypothesize that this is due to differences in the local bathymetry, or character, of the beach," Santucci said. "The exact same wave approaching different types of coasts will result in different breaking waves, which results in different sea spray aerosol production. To adequately capture this effect in a controlled research setting, an artificial shoreline is needed to explore the pertinent variables."

Even without the artificial shoreline, the team has validated the method to generate and assess sea spray aerosols from breaking waves.

"We also investigated the height at which the aerosols traveled and analyzed corrosion along an approximately 3-meter-high tower. We found that most of the large, salt-rich aerosols did not travel as high as the smaller aerosols," Johnson said. "This, in turn, correlated to the higher corrosion rate of metals closer to the water surface than those higher up the tower. For future work, we also want to investigate the horizontal distance these aerosols will travel, which can also help us assess the corrosion risk of infrastructure and assets near the coastline."

This research has the potential to impact naval operations significantly by providing valuable data on the long-term effects of saltwater aerosols on naval assets in all coastal environments: land, sea and air.

Emily Winget is a public affairs specialist with the U.S. Naval Research Laboratory.