My first few dives after open water certification were amazing! I descended with a group and simply followed a divemaster around the reef. I let my mind drift off, losing myself in the beauty of the underwater world. I distractedly gazed at sea fans waving in the current, harassed Christmas Tree Worms, and charged through schools of fish to watch them shatter into a million bits of shimmering color. I would glance up at the divemaster and group every few moments and swim along with them like a duckling following its family. I had no idea where I was going, and I didn't care! I was happy to follow along behind the group.
This behavior continued until I boarded a dive boat full of more advanced divers. My buddy and I were shown a map of the dive site and given free reign to dive without in-water supervision. I relished my newly found freedom until it was time to make my way back to the dive boat. I had no clue where the boat was! I popped up to the surface, visually located the boat, and descended to swim towards the boat. I popped up repeatedly to reorient myself until I reached the boat. Once my buddy and I were back on deck, the crew gave us a stern talking to. Popping up and down to find the dive boat is unacceptable, we learned. This sort of sawtooth dive profile is bad for your body and can increases the risk of decompression illness. It was time to learn some navigation skills, starting with natural navigation.
What is Natural Navigation?:
Natural navigation is a technique for orientation in which a diver uses features of the underwater environment as directional cues. Successfully navigating using natural features takes some practice, but is worth learning. Divers must develop situational awareness, consciously observing and taking note of the underwater features around them. Situational awareness may sound easy – what can be simpler than looking around? Yet, the underwater world is filled with so many beautiful distractions (turtles, rays, coral, etc) that it is easy for a diver to lose himself in the details. Divers (especially new divers) are task loaded underwater. Monitoring depth, dive time, buoyancy and tank pressure consumes attention that could otherwise be used to keep track of surroundings. Navigating by natural navigation requires forethought and a conscious decision to pay attention!
Natural Navigation Begins Before a Dive:
The first step in successfully using natural navigation to traverse a dive site is to become familiar with the features of the dive site before entering the water. Decide on some basic landmarks or cues to use for natural navigation based on a map or dive briefing. Once underwater, a diver simply confirms information that he already is familiar with to navigate the dive site. As an example, a diver may view a map of a coral reef before a dive and decide to swim out against the current with the reef on his left, and return to the boat with the current with the reef on his right. Once he has agreed on this course with his buddy, maintaining orientation during the dive becomes easy.
Depth as Natural Navigation:
A good diver is always aware of his depth during a dive, but not all divers (even great ones!) realize that depth can be a powerful navigational tool. Many dive sites near shore have a gently sloping floor that deepens as the diver moves away from land. A diver who swims progressively deeper along the bottom knows that he is moving away from the shore, and a diver who swims shallower will realize that he is swimming closer to the shore. If a diver's depth does not change, chances are that he is swimming parallel to shore. Of course, this is not always the case, and depth changes for a given dive site may vary (or even be non-existent). A diver should familiarize himself with expected depth variations for a dive site before entering the water.
More tips for easier diving
• 6 Steps to an Easier, Less Stressful Descent
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• How to Deal With Hyperventilation and Panic Underwater
Structures and Topography as Natural Navigation:
Perhaps the most obvious form of natural navigation is navigation by underwater features such as reefs, shipwrecks, walls, and other structures. A dive site map is incredibly useful in determining the layout of a dive site and choosing which features to use as navigational tools before a dive. As an example, the map may indicate a coral reef with an edge along a sandy bottom. Decide where to swim in relation to this edge before the dive. Similarly, a diver who plans to dive shipwreck may decide on his route over the wreck ahead of time using structures and features of the wreck. Slopes, dunes, coral walls, and artificial features such as mooring hooks and man-made debris make great references for natural navigation. In the worst case scenario, a diver without a map can make a quick plan by floating on the surface in clear water, observing the reef, and agreeing on a plan with his buddy before the dive.
Current as Natural Navigation:
A constant current may provide a sense of direction underwater – but be warned currents occasionally shift. Divers who use current to provide a sense of direction should begin the dive by swimming against the current and end the dive by swimming with the current. A diver who attempts to swim perpendicular to the current will find that it pushes him away from his original course. He may have difficulty returning along the same route. If using current as a natural navigation tool, be sure to use back-up references, such as depth and structures, in case the current shifts direction.
Sand Patterns, Sun and Shadows as Natural Navigation:
Familiarity With Typical Underwater Sights Helps:
When I first started diving, all the coral looked the same to me. As I learned more about coral species, I began to differentiate among them. Instead seeing coral, coral, and more coral, I noticed boulder coral, plate coral and elkhorn coral. I learned to distinguish different parts of the reef by the different compositions and arrangements of coral. One navigational trick I now use is to swim from one easily recognizable feature to another. I swim from a coral arch, to a large fan coral, to a interesting boulder coral, etc. I the use the features to back track at the end of the dive. The more a diver learns about the underwater environment he frequents, whether it is a coral reef, a shipwreck, or a lake, the easier it will be for him to pick out underwater features and navigate by them.
Reference and Look Behind You as You Swim:
Divers with good situational awareness use a combination of many of the above navigational techniques to maintain orientation during a dive. However, remember that your chosen visual references may look unfamiliar when viewed from the opposite direction upon return. Periodically look back at the return path to create a series of mental “snapshots” which will help you recognize you return path.
The Take-Home Message About Natural Navigation:
Part of becoming an independent and safe open water diver is learning to find you way around a dive site and back to your point of exit. Natural navigation is a useful and enjoyable way to maintain orientation during a dive.