Water pressure increases linearly with depth. For pure (not salt) water that pressure is about . 432 psi per foot of water. So, at 100 feet depth the pressure due to the water column would be 43.2 psi.
NOTE: Pressure drops by 26 millimeters (mm, about 1 inch) for every 1000 feet above sea level.
At sea level, water pressure is 0 psig. Approximately every 100 feet of sea water depth increases pressure by 44 psig. So, at 500 feet of ocean water depth the pressure would be 220 psig. That's pounds per square inch, gauge.
The thumb rule is every 33 feet underwater increases the pressure by 14.8 psi (1 atmosphere). So 300 feet would be approximately 10 atmospheres or about 148 psi. Assuming a sudden increase from 1 atmosphere to 10, the body would probably be crushed. If they were in specialized diving equipment, then they would be okay.
As you descend into the ocean, pressure increases linearly with depth; there is an increase in pressure of 1 atm for every 10 m increase in depth. So at 1000 m depth the pressure would be 101 atm (100 atm of pressure due to the 1000 m depth, plus the 1 atm that is present at the surface).
So, at 100 feet depth the pressure due to the water column would be 43.2 psi. Add about another 14.5 psi for the pressure of the atmosphere. and the total (absolute) pressure would be about 57.7 psia.
How Deep Can I Dive Before Being Crushed? It's hard to pinpoint a specific depth below which a diver will be crushed. Most recreational divers rarely dive deeper than 130 feet. But commercial divers can use atmospheric suits to descend to depths up to 2,000 feet.
The pressure at a depth of 1000 feet is about 30 atmospheres. This assumes a hydrostatic situation where the water surface is flat.
The water pressure at the site of the Titanic wreck is roughly 6,000 psi (more than 41,000 kilopascals). Under this amount of pressure, even the slightest structural flaw could result in fatal consequences. Death would be virtually instantaneous for the occupants of the pressurised chamber.
A diver at 6 metres (20 ft) may be able to dive for many hours without needing to do decompression stops. At depths greater than 40 metres (131 ft), a diver may have only a few minutes at the deepest part of the dive before decompression stops are needed.
Most people have problem withstanding pressure more than 2 ATM. However, a few deep sea free divers could withstand pressure more than 10 ATMs. The world record deep sea free diving champion (Herbert Nitsch) could withstand pressure of around 25 ATMs by free diving to the depth of 253 metres (830 ft) in 2012.
What happens to your body at 13000 feet underwater? The pressure at 13,000 feet underwater is about 1,000 atmospheres, about 100 times the pressure at sea level. This pressure would have a devastating effect on the human body. The lungs would collapse, and the blood vessels would burst, leading to internal bleeding.
Water has the unfortunate quality of being heavier than air. In fact, it weighs 62.4 pounds per cubic foot. This mass requires a pressure of 0.433 psi to lift water one foot (62.4 lbs/144 in in ft). To put it another way, one psi will lift water 2.31 feet (1/0.433).
When you travel in your vehicle from an area with low elevation, like say New Orleans to an area with high elevation, like say Denver, your tires will experience a slight gain in tire pressure of about two to three PSI. This is because as you rise in elevation, the amount of atmospheric pressure decreases.
At the bottom of the trench, the water column above exerts a pressure of 1,086 bar (15,750 psi), more than 1,071 times the standard atmospheric pressure at sea level. At this pressure, the density of water is increased by 4.96%. The temperature at the bottom is 1 to 4 °C (34 to 39 °F).
The pressure on top of Mount Everest (29,029 ft) averages about 235 mmHg.
The human body can withstand underwater pressure up to a certain limit, depending on the depth and the duration of the dive. According to some sources, the theoretical limit of human body pressure underwater is 1000 m, which is 100 atm of pressure.
Navy SEAL dive training occurs first at the Second Phase (Dive) of BUD's and it's the Combat Divers Coarse. SEALS don't usually dive deep but can push too 100 to 130 feet but diving is mission specific.
Bone crushes at about 24,600 lbs per sq inch. 33 ft=1 atmosphere and one atmosphere=14.6 psi. Thus, somewhere about 22 miles down the bones might be expected to crush. For the purpose theorizing, this leaves the likely dissolution of bone (e.g., calcium remaining in a solid state) at such depths.
While there's no precise depth at which a human would be 'crushed', diving beyond certain limits (around 60 meters) without proper equipment and gas mixes can lead to serious health issues due to the pressure effects on the body, including nitrogen narcosis and oxygen toxicity.
The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1,050 hPa (15.2 psi; 31 inHg), with record highs close to 1,085 hPa (15.74 psi; 32.0 inHg).
Approximately, 14.7 to 19.7 pounds per square inch (Psi) pressure is generated while urination. The urinary bladder stores the urine that is produced by the two kidneys of the body. Around 500 milliliters (mL) to 700 mL of urine can be stored in the urinary bladder at a time.
At a standard atmospheric pressure (1 ATM), blood boils at approximately the same temperature as water: around 100 degrees Celsius, or 212 degrees Fahrenheit. Blood is approximately . 9% salt, which at that concentration would raise the boiling point by less than 1 degree Celsius.