Current Diving: How to Deal with Vertical Currents

Current diving is fantastic, incredible, like flying in the middle of the ocean. In fact, it’s the most common form of diving in Cozumel, and we practice it every day at Dressel Divers. Based on our experience, we wrote the article “Drift Diving: 5 Tips to Enjoy it to the Fullest.” But today we’re going to talk about diving in vertical currents, a type of underwater current that no diver seeks out. You come across these by chance.

I remember once diving with my wife in Sharm el Sheikh, Egypt. Specifically, we were current diving at Yolanda Reef. There is a crack there that goes around Ras Mohamed. Ras Mohamed is a wall that drops 800 meters almost straight down. When we reached the crack, there were about 5,000 large red fish standing at the mouth of the crevice. What a sight! We were so amazed that we didn’t realize the current was splitting in two: one upward current and one downward current. We went through the crack and “Whoooops!” it swallowed us. In the blink of an eye, the depth gauge indicated 40 m/130 ft. At that moment, I looked at my wife and gave her the thumbs up: “Up!”. We kicked to ascend, checked the depth gauge: still 40 meters.

• “What did I tell you? Ascend!” – I signaled to her.
• “I know, what do you think I’m doing?” – She gestured back.

Yes, couples have the gift of arguing underwater. The thing was, no matter how much we kicked to ascend, we weren’t moving. In the end, we grabbed onto the wall. We literally climbed out of there.

That day we learned that:

• We can’t forget that things can change underwater.
• Vertical currents are one of those unexpected changes.
• Knowing why they occur will help you predict and avoid them.
• Knowing how to react if you ever find yourself in a downdraft or upward current will help you get out of them safely.

That’s why we wrote this article.

1. Basic Concepts of Current Diving

1.1. What Submarine Currents Are

Currents are rivers that flow through the oceans. I don’t think there’s a more graphic way to describe these movements of water masses that run through defined routes within an even larger body of water. Their strength is measured in knots, which equals one nautical mile per hour; that is, 1852 m/h.
The movements and distribution of marine species largely depend on them.
Some currents transport warm water from the tropics, while others bring cold water from polar regions. This affects the climates not only of coastal regions but of the entire planet.

1.2. What Current Diving Is

When divers talk about current diving, we generally refer to letting the current carry us to cover great distances effortlessly. It’s another thing to dive against the current, which is something that can only be done if the current is weak.

Many dives start against gentle currents and end with the current, making the return easier.
However, if the current is moderate or strong, forget about this technique. Advancing against them would be futile. In this case, the idea is to go where the water takes you, and that’s why you need a support boat to practice current diving.

1.3. Types of Currents

Marine currents are classified into different categories according to their origin, direction, depth, temperature, and duration.
We will focus on two of them: their origin.

• • Classification by Origin
    • Drift or Drag Currents: Caused by the wind. These are the ones we generally enjoy in current diving and are horizontal.
    • Density Currents: Caused by changes in density produced by variations in temperature and salinity.

Gradient Currents: Caused by the pressure difference between two areas.
The latter are responsible for vertical currents.

1.4. Safety Considerations for Diving in Horizontal Currents

1. Preparation and Prevention:
   • Planning: Research the currents in the diving area before you dive.
   • Equipment in good condition: Check your equipment and make sure everything is working properly.
2. Master Buoyancy: In current diving or drift diving, buoyancy is your ally. Maintaining a horizontal position about 3 feet from the bottom (close without damaging it) will help you adapt to the current easily. If you ascend or move diagonally, the current will push you harder.
3. Don’t Fight the Current: Go with It: Swimming against strong currents is an exhausting and futile effort. Don’t try to beat the ocean! Instead, use the nooks of the reef to slow down and enjoy the ride.
4. Keep Your Buddy Close: Never stray from your dive buddy. If the current separates you, use your surface buoy to ascend and be rescued by the boat. Don’t try to rejoin the group alone.
5. Anticipate the Path: Drift diving takes you through a constantly changing underwater landscape. Reef pinnacles, rock formations… be prepared to navigate these obstacles in advance!

A tip for underwater photography enthusiasts: have your camera ready! You’ll only have one chance to capture that animal you see in the distance.

2. Tips for Dealing with Vertical Currents

Upwelling and downwelling currents are like columns of water that rise and fall, transporting heat, nutrients, and life across the vast ocean expanses.

2.1. How Vertical Currents Form

The formation of these currents has been the subject of study, and there are various theories about their origin. Winds play a role in their appearance. They agitate the ocean surface, generating convergence and pushing the water downward, creating downwelling currents. On the other hand, the sun’s heat warms the surface waters, making them less dense and lighter, which pushes them upward, creating upwelling currents.

One of the most interesting theories suggests that they form when two opposing horizontal currents meet or encounter an obstacle, forming a vertical current or an eddy. In this underwater confrontation, water cannot be compressed, so it is forced to ascend or descend, mostly following the topography of the seabed.

PREVENTION TIP: When you are diving in a marine current and encounter an obstacle—such as a submerged reef wall, an island, or even another current—it is possible that the current carrying you will be deflected upward or downward. Therefore, it is important to stay alert.

Another type of current to watch out for is upwelling. In this case, water rises from the seabed to the surface; these are, therefore, ascending currents of cold water (from the bottom) filled with nutrients. This is great for marine life, but for you, a current diver, it can be quite startling, causing you to ascend too quickly.

PREVENTION TIP: Upwelling areas are known. This will allow you to stay alert and react quickly.

Factors to Consider When Diving in a Vertical Current

IMPORTANT: When you notice a vertical current, regardless of its direction, never swim toward it; retreat.

2.2. Factors to Consider When Current Diving

• Depth, strength, and volume: The deeper, stronger, and more voluminous the current, the greater the effort required to get out of it.
• Distance to the eddy line: The closer you are to the edge of the current, the easier it will be to swim out.
• Topography: The presence of rocks can offer you footholds to climb or grab onto.
• Visibility: Poor visibility makes it difficult to assess the situation and make decisions.
• Risk of entanglement: Be careful with loose items that can get caught in your gear or the environment.
• Equipment: The weight and buoyancy of your diving gear can affect your maneuverability.
• Skills and experience: Your level of training and diving experience will allow you to choose the most appropriate strategy.
• Decompression status: If you are in decompression, it is crucial to avoid rapid ascents that could cause health problems.

2.3. Strategies to Escape a Downdraft

Facing a down draft during a dive can be a challenging situation. While there’s no universal magic formula, there are strategies you can employ to maintain control and safely navigate through it.

If the current is mild, you can simply ignore it and proceed with caution. If the current is strong:

1. Keep calm and control vertical movement: Panicking will worsen the situation. Focus on analyzing the current and acting safely. Your priority should be to avoid uncontrolled ascents or descents. Equalize your ears continuously.
2. Swim diagonally: If the current is a bit stronger, you can try swimming diagonally to the current (limiting water friction) to exit the affected area. This current is like a waterfall. If you get out of it, you will regain control. Once out of the downward current, ascend while moving parallel to the wall, but away from it.
3. Hold onto the wall: If the current is even stronger or the downward flow area is too large, look for a point of support on the wall. You can climb the wall or simply hold onto it to stabilize yourself. Add a small amount of air to your BCD to remain neutral, but avoid adding too much buoyancy, as it could worsen the situation.
4. Use your BCD carefully: Adding air to your BCD can help you ascend, but do so with caution. Too much buoyancy can be dangerous. Only consider this option if there is no other alternative and make sure to follow ascent procedures as much as possible.

2.4. How to Escape an Upward Current

If the current drags you:

1. Stop the ascent as soon as possible. If necessary, hold onto the reef.
2. Vertical position: If you can’t stop your ascent quickly, position yourself vertically to reduce water resistance on your body. This may slow down your movement.
3. Exhale constantly, inhaling only when necessary, and then continue exhaling.
4. Protect your equipment: Cover your regulator and mask to prevent the current from taking them away. If you lose anything, stay calm. Use your octopus and keep breathing. If you can safely retrieve your mask, great, if not, forget it. What’s lost is lost. Close your eyes and protect them with your hands when you need to open them. Your dive buddy will guide you.

Once under control and out of the vertical current:

Begin to ascend at a controlled pace, monitoring your gas supply, as you may breathe faster than normal. This is especially important if the current submerged you at greater depth.

With your buddy: If you can locate your buddy, ascend together, helping each other maintain control and monitoring each other’s gas supply. If possible, perform a safety stop.

In this article, we have reviewed the essential aspects of diving in currents, from basic concepts such as different types of currents to safety considerations to enjoy this activity risk-free. We have learned to deal with vertical currents, which will allow you to fully enjoy current diving and be prepared to act if downward or upward currents arise. Now, there’s only one thing left. It is time to your next current dive! Contact us!