Diving techniques used when faced with underwater currents are presented. Underwater currents can provide a diver with a unique and enjoyable experience. A multitude of techniques are available to help maximize the enjoyment of each experience.
Currents are the silent, unseen “winds” of the underwater environment. You rarely see a current but do see its effect on the environment and can feel its effect on your body. Currents, like winds, give a seascape character and interest. They offer challenges and thrills to divers. Like a gust of wind that appears out of nowhere, a current can sweep through your dive path. Or, you can make a dive knowing you will experience a current.
Diving in currents can be fun, if you know how to maintain control of your position and equipment.
Moving water tugs at dangling equipment and vibrates any projecting gear. You will slip through the water more easily if you’re streamlined.
Consider these equipment modifications to create a streamlined profile:
- Cut off extra long strap ends.
- Where possible, thread fin straps so the end is against your foot.
- Empty BC and wetsuit pockets.
- Wear a low volume mask.
- Eliminate spare or optional hanging equipment, i.e., carry one small light versus a big lantern and a flashlight.
- Use less bulky equipment if practical, such as a smaller BC with fewer pockets and accessories.
- Don’t carry any equipment – such as a goodie bag – in your hands.
- Tuck your glove and boot tops under your wetsuit.
- Evaluate whether to leave your snorkel attached to your mask. If you keep it on the mask, attach the keeper so the snorkel is under the mask strap and held securely against your head.
- If you have a regulator that tends to freeflow easily, consider having a trained technician reset it, so it breathes a little harder but won’t freeflow when it is out of your mouth. This is especially important for your extra second stage.
Some of these modifications are improvements you’ll enjoy for all types of diving. Others, such as using a different BC, are specialized decisions that may only be practical if you plan to current dive frequently. The object of the modifications is to reduce the drag created when the current passes over your body. The more resistance you place against the moving water, the more difficult it is to make a safe, enjoyable dive.
Current diving techniques vary tremendously, depending on the type of current and how your dive is planned. You may elect to ride the current from point A to point B. This is commonly called drift diving.
Swimming against a current may be necessary to reach an upstream destination. If the location is swept with currents but it’s where you want to dive – such as on a wreck – here are some techniques to conserve energy and air.
* Stay close to the bottom, the wreck or the reef. The current is usually a little weaker right on top of a large, immovable object.
* Head into the current with your body presenting as little surface area to it as possible.
* Use your hands to pull yourself along the bottom. You’ll go farther and faster with arm-pull glides versus trying to kick.
* There is a lee behind large objects – duck behind wreck parts or boulders, etc.
* Rethink your likely air consumption. It will be much greater than usual as you work harder to move around. As air consumption goes up, bottom time rapidly decreases.
* Evaluate your intended diving activity. If the current is screaming, it may be beyond your diving and/or photographic ability to take a camera.
* Discuss your dive plan thoroughly with your buddy. It is annoying when you lose sight of a buddy on a regular dive. It can be an emergency on a current dive. Agree to maintain relative positions to each other, i.e., always stay on your buddy’s right side.
Another type of current diving is when you swim out of a current. Many ocean coastal dive sites have longshore currents. These run parallel to shore and may be narrow or wide, gentle or swift. You may need to cross a longshore current to reach an offshore reef. If you are able to stand up on a cliff and view the extended area around a dive site, you’ll probably be able to see a longshore current by the waves or foam moving on the surface.
To cross a longshore current, aim upstream and swim on an angle until you are out of the current. You’ll probably end up opposite your entry point as the water sweeps you downstream. The stronger the current, the more upstream your swimming angle needs to be.
Divers with physics degrees can compute the speed and width of the current as well as the speed of the diver and figure out the exact angle to head upstream to theoretically end up exactly opposite the point of entry. Most sport divers don’t have a need to calculate so precisely and learn by trial and error. The rule of thumb is more current equals more upstream angle.
Just in case you completely blow the crossing, have a downstream exit point selected. If you start across a surface current and realize you aren’t going to make it to calmer water, remember that the shortest distance out of a current is to swim perpendicular to it. If you are getting too tired to continue diving, remember to swim back toward shore. It is easy to get focused on getting across the current and forget that if you abort the dive, you need to turn toward the shore.
Changing depth can help you find calmer water. You can often change your depth as little as 20 feet and notice a difference in the current’s strength. In the Florida Gulf Stream it is amazing the difference depth makes in current intensity – deeper is generally calmer.
Currents in fresh water may exist around springs feeding a lake or where the shore narrows. Two lakes often connect and, at the strait, there will be a flow that feels like a current. (That’s why northern lakes have weak ice near bridges and snowmobiles and kids frequently fall through thin ice there.)
Tidal currents are also part of coastal diving. In many places the only time an area is safe for diving is during the slack tide. Careful timing is required in order to be suiting up just before the tide stops running so you begin a dive at the tail end of a tidal cycle and conclude the dive as the tide reverses and begins flowing. Slack tide offers a calmer environment and better visibility. Plan ahead on your entry and exit points or you may end up quite a distance from your intended shore location after the tide changes.
Like most types of new activities, current swimming may be more enjoyable if you try it first with someone who’s more experienced. Ask the old salts why they do things a certain way, what to watch for or what to do if the plan goes haywire. Pick their brains about the easy way to dive in a current.
Current diving can be nearly effortless – you are swept along by an invisible force. It can also be a frightening experience if you feel out of control. The difference is often based on the diver’s comfort level, ability to adapt as the environment changes and knowledge of waves and currents.
Anytime you dive in moving water, think: reduce drag. Make your profile as sleek and uncluttered as possible. The less drag on your body, the less energy it takes to move through a current. Less energy consumption means using less air and having more time underwater – the reason you learned to scuba dive!