February 23, 2024

The U.S. Navy recently completed tank testing of a new deep-sea diving suit called the Deep Sea Expeditionary Non-Decompression (DSEND) system, which is lightweight and flexible and maintains sea-level internal pressure around the wearer even when hundreds of feet underwater .

Modern scuba gear makes diving a fun and relatively safe sport, but deep-sea diving is the equivalent of spacewalking. Working under crushing pressure at depths of hundreds of feet requires complex equipment and a choice between two challenging and expensive alternatives.

One option is to use a mixed gas diving system, where the nitrogen in the air is replaced by different mixtures of helium and hydrogen, with the percentage of oxygen kept within tolerable concentrations. This is a tricky operation, requiring the diver to be supplied with a large gas mixture while a constant flow of hot water is delivered through an umbilical hose into a special suit that prevents the diver from getting wet even in “warm” water. freeze to death.

It also means that divers have to be under pressure in special surface compartments on the main ship, transfer to the required depth in a diving bell, return to the surface compartment when the job is done, remain under pressure for days or weeks to complete their watch, and then Take a few days to decompress.

Not only is it very complicated, it’s expensive – not only in terms of equipment and gas, but also in terms of dive fees, and for a civilian diver, it’s timed from the moment you enter pressure to the moment you exit. That’s a lot of cash.

DSEND is lightweight and flexible
DSEND is lightweight and flexible

us navy

Another option is to wear diving armor, a metal alloy suit that keeps a diver at normal sea-level pressure throughout the dive. Because a spacesuit has to withstand pressures of, say, over 18 atmospheres at 600 feet (183 meters), it has to be very heavy, and the joints in the arms and legs and the articulated claws of what should be the hands have to be equally strong. Such devices are very bulky and are usually equipped with electric thrusters to move them. It also requires a boat with heavy lifting gear and assists scuba divers to help armor divers.

The DSEND project aims to avoid both options, at least at depths below 300 feet (92 meters), using lightweight suits made of hard and durable materials with their own internal life support systems. This allows divers not only to avoid the danger of bending and the need to decompress to return to the surface, but also to move and even swim underwater more easily.

Developed in collaboration with Naval Sea Systems Command (NAVSEA), Naval Underwater Warfare Center (NUWC) and Naval Surface Warfare Center (NSWC) in Panama City, DSEND features joints, grippers and hand attachments made from novel materials , can be adjusted to suit the diver. The joints are designed to more closely mimic those of humans, making them easier to move with less focus and effort.

The most recent tests took place at the NSWC Carderock Division in Maryland and the Naval Experimental Diving Team in Florida, where it was used to simulate a rescue and salvage operation of a hypothetical downed aircraft with a mannequin as the casualty.

“DSEND is really a game-changer because it’s a self-contained environment that keeps the internal pressure steady as divers descend to depths as the external pressure increases,” said San Francisco, a program officer at the Office of Naval Research (ONR). Dr. De La Chapman said. ) Warfighter Performance Division. “It improves diver safety, allowing them to extend their operating envelope and eliminate lengthy decompression times.”

DSEND is currently rated for 300 feet (91 m), although efforts are underway to improve this.

source: office of naval research