8 Tips for Better Underwater Navigation | Scuba Diving

8 Tips for Better Underwater Navigation

underwater navigation tips for using a compass

It's not fun being lost underwater — use your navigation skills to find your way home every time you dive.


Recently, I was diving with a friend in the Florida Keys. The conditions were good: no current and decent visibility on a shallow reef. He was chasing lobster; I was chasing my camera's viewfinder. We both spent more time on our respective pursuits than on watching the reef, and eventually, we looked at each other and exchanged the sign for "Where's the boat?" hoping the other knew the answer. Neither of us did. We spun around in the water, trying to catch a glimpse of the hull on the surface. Doubt immediately crept into my mind. How far were we going to have to swim? What if we took off in the wrong direction? How would the boat crew find us?

There are many reasons for bettering your underwater navigation skills, but put simply, it makes it possible for you to find your way home. Natural navigation requires you to use the physical contours and characteristics of the dive site to guide your way out and then find your way back, and learning to combine natural navigation with basic compass skills practically ensures you'll never get lost underwater. Here are eight steps for getting to the reef or wreck and back again.

Get briefed

Good navigation starts before you even get in the water. If you and your buddy are diving independently, get a thorough site description — and a map, if possible — from a local dive shop or other divers at the site. If you're on a chartered dive boat, pay close attention to the divemaster's briefing. He or she can impart valuable information about the site's features, depth range and currents so you and your buddy can create a dive plan. Discuss your profile and the time or air pressure at which you'll turn around, and decide on a basic route.

Follow the leader

One diver should take the lead before you even get in the water. It isn't practical for both divers in a buddy pair to attempt to navigate on a dive. If you're leading, concentrate on the planned path. Your buddy should monitor time, depth and distance.

Start at the beginning

If diving from a boat, enter the water and either surface swim to the mooring or anchor line and descend there, or drop down behind the boat and swim underwater to the mooring or anchor. Always start your dive at the point where the boat connects to the bottom. When diving from the beach, surface swim past the waves to where you plan to make your descent.

Whether diving from the beach or the boat, natural navigation starts as soon as your head goes under the water. "Upon descent make a good note of natural references like sand patches, rock formations, pillar corals, brain corals or whatever," advises Andy Phillips, director of professional training for Utila Dive Centre in Honduras. If you make mental notes of features you can remember, you can use those physical markers to find your way back.

Watch the clock

Swim away from your starting point for a predetermined length of time, and then turn around and swim roughly the same length of time back the opposite direction. If there's current, head into it on the way out — in this case, the return trip won't take quite as long. Watch your air consumption as well. It's a good idea to follow the rule of thirds: Use one-third of your air on the way out, one-third on the way back and leave one-third for exploring near the boat and making a safety stop.

Pay attention

Make note of the unique features or characteristics of the dive site that can make navigating as simple as a walk in the park. For example:

Pick a Path. The best navigational marker is a dedicated line you can follow like a hiking trail. At many sites, this may be a sand channel or the edge of the reef where it meets the sand. Another easy path to follow is a specific depth contour on a sloped reef or wall. For example, you and your buddy can plan to descend along a sloped reef to 60 feet, then turn, swimming with the reef on your right and maintaining a constant 60-foot depth. To find your way back, turn 180 degrees so the reef is on your left and continue at the same depth.

Look for Landmarks. On many dive sites, you'll find distinct coral formations, objects or differences in the bottom's contour. Keep an eye out for anything that stands out, and make note of the depth. You may pass a swim-through at 70 feet, an anchor on the seafloor at 90 feet or a sand channel at 40 feet that runs perpendicular to shore. Use these landmarks to guide you on the way back.

Follow the Light. "Check the sunlight angle at the start of your dive and try to confirm this when you begin your descent," Phillips says. If you head into the sun at the beginning of the dive, you should have the sun at your back when you turn around. And if you're diving off a big boat, look for the boat's shadow on the seafloor when you think you're getting close.

Watch the Water. How the water moves can tell you a lot about the general direction you should go. Close to shore, the constant back-and-forth motion you feel as waves pass overhead is called surge. The wave push headed toward the beach is always going to be stronger than the return surge. This will always give you the general direction of the beach. Constant wave action also creates ripples on the sand bottom that run parallel to the shoreline.

underwater navigation tips for using a compass

As you begin your dive, try to remember unique underwater features to help you stay on course when you turn the dive.


Check Your Compass

"In tropical waters, even though it's clear, the ease of seeing what's around can often lull you into a false sense of security," Phillips says. "You can lose reference easily and get distracted. I've known many low-vis divers who've had difficulty adapting to tropical-water navigation. They think they can drop the compass and autopilot back to the boat."

As you swim, line up the long line on your compass, called the lubber line, with your body and the direction you want to swim. Proper positioning is very important. Hold the compass with two hands in front of your body. Using one hand often allows the lubber line to drift off course, and so will you. You'll also need to keep the compass flat so the wheel inside can spin freely.

While swimming, periodically wiggle the compass to make sure it's level. Do not fixate on the compass, but instead look over and beyond the compass with frequent glances to make sure you don't drift off course. When taking a heading, rotate the bezel on top of the compass until the hatch marks meet the North arrow. As long as you keep the compass flat and the North arrow between those marks, you should swim straight. To reverse course, simply turn around until the North arrow points toward the marks on the other side of the bezel.

Go slow

Not only will you pay more attention to where you're going, you'll stay closer to the boat or shore, further reducing your chances of getting lost. Honestly, the reef is pretty much the same whether you're at the boat or 300 yards away, so there's little reason to go a long distance, and a relaxed attitude will not only help you conserve air, but you'll be surprised by how much more you see.

Take a peek

At a relatively shallow site, you can always make a normal ascent to the surface and find the boat. If you know you're lost, this is much better than swimming off in a random direction you think will lead you back. When you do come up away from the boat — and we all do it at some point — listen carefully for boat engines and avoid surfacing if you think a boat is passing nearby. Once on the surface, turn 360 degrees until you see your boat, then give the crew the OK signal, so they know you're not in trouble.

Cressi Leonardo 3 Console Dive Computer

Cressi Leonardo 3 Console Dive Computer

Courtesy Cressi

Get the right gear

Cressi’s Leonardo dive computer has a long history of high performance. It earned a Best Buy in ScubaLab’s 2011 dive computer test. Its top-notch performance continues in the newest version of the Leonardo, the 3. Simplicity and ease of use are the hallmarks of this dive computer — it has a single button interface for effortless programming in three gas modes — but the Leonardo is still packed with features. Its long list of capabilities includes Cressi’s special RGBM algorithm with three diver-programmable safety levels, an optional Deep Stop function, and a 70-hour or 60-dive logbook. Pair it with Cressi’s multi-color mini-submersible pressure gauge in a rugged, low-profile case, and you have the Leonardo Console 3, a gauge combo that simply can’t be beat. And when you need a compass to help you find your way underwater, the Leonardo's onboard compass is dependable, accurate and easy to use.

Compass Specs:

• Luminous Face • 10° Sections Face Division • Windows for Side Scan and Sight Accuracy • Rotating Bezel with Compass Rose & Double References • Lubber Line • Liquid-Filled Compass for Very Smooth Operation • Accurate Navigation

FOR MORE INFO: cressiusa.com