5 Terrifying Things Hidden Under the Sea
Dark5
A video that circulated in recent years depicts a violent underwater phenomenon known as Delta P. The brief clip shows a crab nearing a small cut in an underwater gas pipe. As it nears the opening, it appears to be sucked towards it.
The creature then flails and struggles for a brief moment as it is held against the opening by the pull of the pressure change before being ripped through the tiny crack entirely.
The term Delta P is shorthand for ‘differential pressure.’ This terrifying phenomenon poses a particular hazard to commercial divers and underwater construction workers, many of whom fear it above anything else.
Delta P is responsible for two out of three commercial diving fatalities and is well known amongst divers for the grisly nature with which it dispatches those who stray too close.
Differential pressure causes a rapid and powerful rush of water from an area of high pressure to one of lower pressure, which can draw objects into gaps that would otherwise be impossibly small for them to pass through.
The force of the flow through the bottleneck can amount to as much as hundreds of pounds per square inch. Delta P situations commonly occur around thrusters, intakes, pumps, and when water floods into a gas void such as an underwater pipeline.
One devastating example occurred in 2015 when 39-year-old occupational diver Luke Seabrook was making a routine inspection of a sluice gate at the Nova Scotia Power dam. Tragically, the gate had not closed properly, and Luke became pinned to an opening, unable to escape the pull of the water flowing into the reservoir.
Underwater welders are at particularly high risk of encountering Delta P. In February 2022, a group of five divers was carrying out maintenance work in the Gulf of Paria when a safety valve failed, creating a powerful vacuum that sucked all five into the pipe. While one was rescued, the others remained missing for days before finally being found dead, crushed inside the pipe.
As a part of their training, divers are now shown cautionary educational videos explaining how these accidents can happen...
In these videos, disturbing animations reveal how divers can - and have - become trapped and drowned or forced through narrow openings through which no human could survive. On many occasions, the force has been strong enough to tear divers off their umbilical safety lines, leaving them entirely at the mercy of the forces of Delta P.
On Luke Seabrook’s death, a consultant for the Occupational Diving Safety Association said, quote, “You don’t see it. You don’t hear it. It’s usually too late...”
