Navy Dive Shirts Crushed It!

Crush Depth – The designed depth at which the pressure hull of a submarine will collapse. At depths greater than 40 metres (130 ft), a diver may have only a few minutes at the deepest part of the dive before decompression stops are needed. In the event of an emergency the diver cannot make an immediate ascent to the surface without risking decompression sickness.

From an article in Wired: 

Navy Divers are always finding ways to go deeper:

(excerpted: https://www.wired.com/2013/02/diving/ 

MOVING AROUND UNDERWATER in a diving suit is a lot less fun than it sounds. To survive at the deepest depths, divers need enormous, cumbersome, pressure-resistant suits that limit their mobility. But the Navy is sick of trading survivability for flexibility, no matter how far into the briny deep its divers wade.

In the Navy’s most recent round of technology solicitations to small businesses, the seafaring service is looking for someone to develop a lightweight atmospheric diving suit that weighs under 400 pounds and can withstand pressure at 1,000 feet below sea level. If the weight requirement still sounds pretty heavy, consider that the current generation of deep-sea suits can weigh thousands of pounds, limiting what divers can do in them.

According to the solicitation, the new diving suit is for “expeditionary diving and salvage forces” (.pdf) and retrieving “high value material” in “austere environments.” Unlike the bulky suits divers currently wear – really more like one-person submarines – these might be light enough so divers can propel themselves with their own feet. (Current models use thrusters, not divers’ legs.)

Still, a wetsuit this ain’t: It’s still a self-contained pressure suit.

It’s also extremely dangerous to dive below a few hundred feet without one of these single-serving subs. Below 500 feet, a neurological disorder called high-pressure nervous syndrome can kick in, which can lead to drowsiness and tremors. Breathing nitrogen and oxygen at depths below 300 feet can also cause blackouts and even death. Saturation diving, which relies on gradually acclimating to underwater pressure over time, isn’t perfect either. Surfacing too quickly can result in the bends, a form of decompression sickness caused by nitrogen bubbles expanding and becoming stuck in vital organs.