Entering against the current helps you stay in control right from the moment you step into the water. When you move into the water while facing the flow, you can begin your descent under your own power and keep a stable position near the boat and your buddy. This minimizes being swept toward hazards like the anchor line, stern, or any prop wash, and it makes it easier to assess surface conditions and establish your orientation. If you enter with the current, you’re more likely to be pushed toward hazards or drift away from your buddy, which increases risk. Entering from downstream or upstream without facing the current also reduces your initial control, so the safest, most manageable option is to go in against the prevailing current.

Displacement clearing uses a gentle, efficient exhalation to push water out of the snorkel by moving the head and jaw just enough to create a flow, without needing a big blast of air. You stay relaxed, keep the mouth around the mouthpiece, and let the breath you already have in your lungs do the work of displacing the water. This takes less energy than forcing air through a purge valve or coughing to blast water out, and it’s not about pinching the nose—nose pinching is more about clearing a mask. So, by relying on a small, controlled displacement of water with minimal muscular effort, this method requires the least energy.

DAN functions as a global medical support system for divers, focused on emergency guidance and access to specialized treatment. It coordinates dive-related medical care by linking divers with diving physicians and hyperbaric facilities around the world, so someone with a decompression illness or other dive injury can get timely, appropriate treatment. While it does offer training and insurance products, the defining feature is this worldwide emergency network of hyperbaric chambers and dive medicine experts. That makes the description of a worldwide emergency network the best fit.

Neutral buoyancy means your total buoyant force equals your weight, so you neither rise nor sink in the water. For a buoyancy check, you adjust your gear so that with a normal breath you hover at eye level. Eye level is a practical, repeatable reference point that keeps you in a comfortable part of the water column while you learn to control depth with small breathing changes. If you float higher than eye level (toward the surface) you’re positively buoyant; if you sink below eye level, you’re negatively buoyant. Reaching neutral buoyancy at eye level with a normal breath confirms your buoyancy balance and helps you maintain depth during a dive.