Diving in strong currents is one of the biggest fears of many divers, but a delight for others. When we are consulted about diving destinations or we are asked for a quote for a trip, the subject of current usually comes up: “Is it a place where there are strong currents?” or “We don’t have much experience and we are a bit scared of strong currents” are topics that come up when clients consider diving in famous places like Komodo, Maldives or Galapagos, for example. In fact, most of the places where we can dive with big predators like sharks or where we find manta rays receive currents regularly.
Strong currents can be common in areas such as the above, in a single dive site or they can be fortuitous in an area where there are supposed to be no currents. We can also find different types of currents such as ascending or descending, on the surface or on the bottom… it is not superfluous to know what to do when we dive with currents in order to always dive safely. Here we will explain the different types of currents and how to deal with them in order to avoid them with peace of mind and even enjoy them. The most important thing when you are caught in a current is to keep a cool head, stop, think and act accordingly.
Vertical currents are currents strong enough to push you to the surface or to the bottom. Yes, as you can imagine, they can be dangerous and disconcerting.
What are updrafts and downdrafts or vertical currents? An updraft is a mass of water that comes from deeper water and pushes everything in its path toward the surface, including you. A downdraft, on the other hand, is a current that starts in shallow water and rushes over the edge of a wall and flows downward. These currents can occur when two currents in opposite directions collide and head toward the bottom or toward the surface.
What to do if we encounter either of these two currents? If it is a descending current we must follow these steps:
- Change direction and dive parallel to the wall. These currents behave like waterfalls and moving a few meters will be enough to avoid that tongue of water that pushes us to the bottom.
- Add air to your BCD. By adding air we fight against that force that submerges us, and at the same time we must swim in parallel to avoid that waterfall we mentioned. It is even possible that, if it is very powerful, we will have to inflate the BCD completely and unload the weights. Once we get out, quickly unload air from your BCD and restore your buoyancy and try to reach the wall to avoid an uncontrolled ascent.
- Drift with it. If all else fails, stay calm. Descent currents lose strength as they deepen. Once it has weakened move left or right out of it, and gradually ascend. When ascending, keep an eye on your dive computer and make all required safety stops.
And what do we do if the current is upward?
- Reverse your direction and flap parallel to the wall. As with the downdraft, it is possible to escape the power of an updraft if you realize it before you fully enter the water tongue.
- Empty your BCD. Exactly the opposite of downdraft currents. This will help slow your ascent and prevent a decompression accident. If you find yourself in a very strong current that takes you straight to the surface, flex your arms and legs, continue to deflate your BCD, and, very importantly, don’t forget to exhale the air from your lungs.
- Launch your surface buoy. Launch the buoy as soon as you have exited the rising water column so that the boat crew will come for you. Make safety stops as necessary.
Tidal currents are masses of coastal water that travel from the ocean to the coast and vice versa thanks to the attraction of the moon, generating huge underwater rivers that can be both ascending and descending. These tides in the open ocean do not have a great impact, but in areas close to the coast or in channels they are of great intensity. What to do to avoid encountering one of these currents?
- Check local tide tables and schedules. Plan your dive taking into account the currents and their schedules. If you have no experience with the tidal currents or the dive sites of each area do not hesitate, hire a local dive center, they know the easiest entry and exit points according to the tide.
- Consider diving during a slack tide. When you will find less current it will be during slack high tide and low tide.
- Bring the right equipment. A buoy as well as a whistle and a watch with which you can know how much time is left before the tide change will be almost essential to have a safe dive. Another interesting point during planning will be to set two exit points in case one of them is receiving a stronger current than expected.
- Share your dive plan. Tell someone who doesn’t dive with you what your plan is. And if you have someone waiting for you on the shore who knows the plan, all the better, so if you get swept by a current the search team will find you much sooner.
When we are performing a dive within a liveaboard program that is not planned to be a drift dive (entry and exit are not performed at the same point) and we are going to enter the water with current we must follow these steps to complete it safely:
- Pay attention to the briefing. If there is a surface current before entering, the boat crew will have specific instructions on how to enter the water, including going down from the leader line together. These lines are dragged from the stern of the boat and we must always maintain contact with the line because even if we momentarily let go of the line we could be carried away by the current.
- Pay attention to your surroundings. At depth we can find out and predict which way the current is moving by observing marine life. Soft corals and vegetation move in the direction of the current and fish face the current. Start the dive by swimming against the current so that once you finish the dive, you can swim back to the exit point more easily.
- Descend. If the current increases, changes direction or appears unexpectedly during the dive, try descending a little, to where the current loses strength. In general, the current is strongest at the surface or in mid-water and will weaken the more you stick to the bottom.
- Stay together. If part of the group is left behind by the current, wait for them on a reef ledge. Air consumption in current situations increases and it is important that the more divers are together the better in case you have to share air with a diver in trouble.
- Cancel the dive if necessary. If the current is too strong and you do not feel comfortable, it is best to abort the dive. If you are in a group, don’t be surprised when the guide stops the dive if the current is too strong. One of its missions is not to put any diver’s life at risk.
- Follow the briefing until you exit the water. Follow the instructions of the divemasters and guides at all times until the dive is over. The briefing is sure to have included information on how to get to the boat safely. When you have finished the dive, keep hold of the line and do not let go until you have removed your fins, BCD and can safely climb aboard. Keep the regulator in your mouth until you remove your BCD.
There are dive sites in many parts of the world known as Washing Machines or vortex (also called vortex), dives where the current is powerful and has an irregular behavior, it can trap you in a whirlpool that makes you spin.
These dives can be fun if we like this type of diving and we know how to deal with them and we are prepared… but if it is unexpected and has not been discussed in the briefing they can be very unpleasant and dangerous.
This example of a vortex current experienced by a diver in Socorro Island is both revealing and distressing.
These types of situations occur when the surrounding currents bounce with the bottom topography or between two currents going in opposite directions, creating spirals of water flows. A telltale sign of a vortex current is to see a sort of bubble snake that spins on itself. When you find yourself in this type of current you may feel the current catch you and keep you spinning around the vortex, or push you out of it. They are very disorienting and frightening currents and fortunately they are rare. What can we do if we get caught in a vortex current?
- Swim horizontally. As with updrafts and downdrafts, try to exit the current horizontally, the current is always weaker at the edges.
- Hold your equipment tightly. These currents are often powerful and if you are careless, they can take off your regulator and mask. Grab them as soon as you feel you are entering a washing machine.
- Let yourself go. This is another option, if it is not too strong and you feel comfortable, enjoy the moment! These currents dissipate after a few seconds so when the trip is over, regain your buoyancy and end the dive if you consider it appropriate. Putting yourself in the fetal position will sooner or later push you out. The most important thing is to stay calm, watch the depth gauge so you don’t go any deeper or shallower than you should and try to breathe calmly.