At what depth is the gauge pressure equal to 1 ATA in sea water?

Gauge pressure is the pressure exerted by a fluid at a given depth, exclusive of atmospheric pressure. In the case of scuba diving in seawater, the pressure increases with depth due to the weight of the water above.

At sea level, we experience an atmospheric pressure of approximately 1 ATA (atmosphere absolute). As we descend into the water, the pressure increases because of the water above us. Generally, for seawater, pressure increases by approximately 1 ATA for every 33 feet of depth.

Therefore, at a depth of 33 feet in seawater, the pressure due to the water would be 1 ATA. When you combine this with the atmospheric pressure at the surface (1 ATA), the total pressure at this depth is 2 ATA, which is why gauge pressure is considered to equal 1 ATA at this depth.

This relationship between depth and pressure helps divers understand how much pressure they will be experiencing as they go deeper underwater, ensuring they're prepared and able to manage their dive safely.