Avoid Problems Associated With Diving in Poor Visibility and in Very Clear Water

 

 

 

 

 

 

 

 

 

 

 

Avoid Problems Associated With Diving in Poor Visibility and in Very Clear Water

Severe reduction in underwater visibility presents challenges when scuba diving. Poor visibility makes communication using hand signals more difficult, makes navigation by visual references tricky, and can cause disorientation as to depth and direction. However, many divers do not realize that diving in very clear water can also present difficulties. In very clear water, other divers appear deceptively near (water's magnifying effects make objects appear nearer and larger), leading divers to inadvertently stray too far from their buddies. Many divers also find that gauging depth and distance in very clear water is challenging. In some cases, divers have reported the sensation of vertigo when looking down through very clear water. Here is my advice on how to avoid problems associated with diving in both clear and turbid water.

Considerations for Diving in Reduced Visibility:

Diving in reduced visibility can be disorienting for divers who are not prepared for it. However, with proper precautions and techniques, diving in poor visibility can still be enjoyable! Reduced visibility challenges divers to hone their navigational and referencing techniques, and allows them to experience a greater variety of dive environments than divers who shy away from situations with poor visibility. Here are techniques for making diving in reduced visibility easier.

 

1. Referencing:

Learning to use a variety of references to maintain orientation greatly increases a diver's sense of control and enjoyment in poor visibility. The most obvious references are a diver's gauges, including his depth gauge and his compass. A diver should be sure to check his gauges frequently during a dive in reduced visibility to maintain awareness of his depth and direction.

Other methods of referencing exist. For example, a diver who becomes confused as to which direction is up may observe his exhaled bubbles to reorient himself, because bubbles float upwards. A diver's ears provide information about his depth. If a diver is attempting to maintain a constant depth but feels the need to equalize his ears, he can be sure that he has inadvertently descended. Similarly, a diver who feels the need to equalize his ears more quickly than usual during his descent will know that he has exceeded his normal descent rate.

Finally, many divers find descent and ascent lines useful. These are sturdy ropes attached to a point on the surface (such as a buoy) and a point on the bottom. Not only do these lines provide a physical reference (a diver can grab the line to stabilize himself), a diver who uses a descent/ascent line will be sure that he descends and surfaces in the expected location. During shore dives, the natural contour of the floor may be used to maintain orientation in a similar manner.

2. Communication:

In very poor visibility, a diver may find it difficult to see his buddy's hand signals, or even to find his buddy! A diver in reduced visibility must take extra care to remain close enough to his buddy to effectively communicate problems in an emergency. Special training is helpful (and in some cases required) to dive in areas where extremely poor visibility is likely. As an example, cave divers, who face the possibility of zero visibility due to light failures or silt-outs, learn to communicate and respond to emergencies by touch. In areas where a halocline is responsible for poor visibility, divers may use light signals to communicate.

3. Navigation:

If the visibility underwater is poor, navigation by visual references becomes difficult and divers must rely on other clues to successfully explore a dive site. The ability to navigate using a compass becomes important in low visibility, which is why this skill is taught during open water certification. However, compasses are not the only way to navigate in poor visibility. During wreck and cave diving courses, divers learn to navigate by using a guideline, which they place to mark their return route to the open water. Learning to effectively and safely deploy a guideline takes practice and special techniques, do not attempt to deploy a guideline without training.

 

Considerations for Diving in Clear Water:

Surprisingly, clear water can also be disorienting. Underwater, objects appear about one third closer and larger than they really are due to the magnifying properties of water. This creates some issues when diving in exceptionally clear water. Here are some points to consider:

 1. Buddy Distance:

One concern when diving in very clear water is that divers tend to think that their buddies are closer than they are, leading divers to stray dangerously far apart. In general, a diver should be close enough to his buddy to be able to call his attention and access his alternate air source regulator in a matter of seconds.

 2. Depth Judgement:

In very clear water, the bottom may appear much closer than it actually is. Divers have been known to misjudge the depth of the bottom (or the distance to the surface) and descend deeper than originally intended. A diver should be sure to carefully monitor his depth gauge to avoid exceeding his planned maximum depth in clear water. He can also use references such as the pressure in his ears to notice if he is descending too far or too quickly.

 3. Vertigo:

Some divers can experience the sensation of vertigo when looking down through very clear water. The best way for a diver to control the sensation of vertigo is to use a visual or physical reference point to orient himself during ascent and descent, such as an ascent/descent line or the natural floor (in the case of shore dive). In the worst case scenario, a diver experiencing extreme dizziness can grab the line or touch the floor to steady himself. If the sensation of vertigo does not pass after a few moments, end the dive.

 

The Take-Home Message About Diving in Exceptionally Clear or Turbid Water:

Both clear and turbid water can cause divers to become disoriented. Determine the expected visibility before a dive and adjust the dive plan accordingly. If the visibility ever causes a diver to feel uncomfortable, impedes a diver's ability to control his depth or position in the water, or makes communication between buddies difficult, it is time to end the dive.

10 Tips for Divers to Protect the Ocean Planet

When you become immersed in an outdoor lifestyle sport like diving, most likely, you have an affinity or a deep love, even, for the underwater world. You'll probably want to know how to be a ‘good' diver and then eventually, how to use your skills to help protect the dive sites you love most.

 

Just like climbers and campers have an ethic or code to live by – so do scuba divers. Project AWARE first launched an ethic more than two decades ago. Today, it's no secret that the world – including the underwater world – is changing rapidly. This includes the ever-increasing and shifting threats to our ocean planet. But also the way we live, travel and even the way we learn to dive is evolving. When thinking about overhauling the Project AWARE philosophy for divers. The focus was on top ocean issues globally – specifically where individual scuba divers can make a difference when they travel, dive, photograph and more.

Divers share a deep connection with the ocean. You can make a difference for ocean protection every time you dive, travel and more.

Be a Buoyancy Expert

Underwater plants and animals are more fragile than they appear. The swipe of a fin, bump of your camera or even a touch can destroy
decades of coral growth, damage a plant or harm an animal. Streamline your scuba and photo gear, keep your dive skills sharp, perfect your underwater photo techniques and continue your dive training to fine-tune your skills. Always be aware of your body, dive gear and photo equipment to avoid contact with the natural environment.

 

Be a Role Model

New scuba divers are being trained and certified every day. Regardless of your experience level, be sure to set a good example for others when interacting with the environment – while underwater and on land.

Take Only Photos - Leave Only Bubbles

Nearly everything natural found underwater is alive or will be used by a living creature. If you take a coral, shell or animal, you can disturb the delicate balance and add to the depletion of dive sites for future generations.

 

Protect Underwater Life

Choose not to touch, feed, handle, chase or ride anything underwater. Your actions may stress the animal, interrupt feeding and mating behaviour or provoke aggressive behaviour. Understand and respect underwater life and follow all local laws and regulations.

Become a Debris Activist

An astonishing amount of waste makes its way underwater, reaching even the most remote ocean areas. Once there, it kills wildlife, destroys habitats and threatens our health and economy. Don't let your dives go to waste. Remove and report what doesn't belong underwater every time you dive. Make a conscious effort to buy green, buy local and, when possible, buy less.

Make Responsible Seafood Choices

Overfishing leads to species declines while harmful fishing practices damage and pollute underwater ecosystems. You play a critical role as a consumer. If seafood is part of your meal selection, ensure you're choosing sustainably sourced species and encourage others, including restaurants and shop owners, to do the same.

Take Action

Scuba divers are some of the strongest ocean advocates on the planet. Now, more than ever, divers like you are taking a stand. Speak out for conservation, share your underwater images, and report environmental damage to authorities and campaign for change.

Be an Eco-tourist

Make informed decisions when choosing and visiting a destination. Choose facilities dedicated to responsible social and environmental business practices that include water conservation, energy reduction, proper waste disposal, use of mooring buoys and respect for local cultures, laws and regulations.

Shrink Your Carbon Footprint

Global warming and ocean acidification are putting your favourite animals and the whole ocean planet at risk. Do your part by understanding and reducing your carbon footprint and look for ways to offset what you can't reduce.

Give Back

Ocean protection depends on all of our actions, large and small. Investing in the ocean protects our planet and lets the dive adventure live on. Donate or fundraise for ocean protection to fuel the grassroots action and policy change necessary to ensure a clean, healthy ocean planet.

The Unity - Wreck - Scotland

A small wreck with a big reputation on Scotland's east coast - a trawler that sank in the 1990s.  Illustration by Max Ellis

HAVING FOUNDERED JUST A FEW MILES out from Lossiemouth, the steel-hulled trawler Unity is virtually the house reef. The seabed is at 24m, so the Unity is accessible to all divers who have progressed beyond basic open water qualifications. As with the vast majority of the Moray Firth, there is no current or slack water to worry about, so the Unity can be dived at any state of the tide, either as a quick trip out for a single dive or as a convenient second dive on the way back in from a deeper wreck. There is usually a buoy attached to the bow, so this is where our tour begins (1). Or rather, this is where the real tour begins, because the first thing to look out for when diving the Unity are the famous Moray Firth dolphins, riding the bow wave of the dive-boat on the journey out from Lossiemouth. Anyway, back to the wreck. The railing around the bow is mostly intact, and both the railing and the bow itself are covered in anemones. At 20m, this is the shallowest point of the wreck. What little current there is concentrates a cloud of fish about the tip of the bow. Also centred here is an old tyre set as a fender - an arrangement not out of place on a working boat like the Unity, though it amazes me that old tyres are still used as fenders on far posher ships. I suppose that any trendy modern purpose-built alternative would end up looking like an old tyre anyway. Further back on the starboard side of the bow, the railings have collapsed inward. At the centre of the deck, a diagonally set square base (2) is the mounting point for a small anchor winch. Behind this, just before the forecastle steps down to the main deck, a circular hole marks where the forward mast would have been. Like many other fittings, the steps were removed when the Unity was stripped in Lossiemouth before the hull was towed to the breakers' yard. Fortunately for us divers, the Unity foundered under tow, so the final breaking never happened. Over the side of the bow and about level with the base from the anchor winch, each side of the forecastle is pierced by a small porthole (3), with another old tyre set as a fender at the back of the forecastle. Behind the forecastle, stooped hatches lead back inside (4), though there is nothing to see other than accumulated silt. The hatch cover from the first hold is slid forwards, leaving the hold open. The second hold is also open, with no sign of the associated hatch. As in the forecastle, silt is beginning to accumulate in the holds, though ribs from the hull are still showing through. A heavy H-shaped frame is set diagonally on the deck between these two holds (5), the base from part of the catch-sorting and processing machinery. A set of three parallel pipes leads from here and out through the gunwale on the port side (6). Decaying ropes are tucked in beneath the gunwale most of the way aft. The wreck is rolled slightly to port so that the port main deck is a metre or two closer to the seabed than the starboard side. Towards the aft of the main deck, this brings the port side almost level with the seabed. Across the wreck on the starboard side, an engineer's vice, similar to any that would be found in a home workshop, is welded to the starboard gunwale (7). Continuing aft, the third and last hold is also open, with no sign of the hatch cover. A tripod mast that has fallen across the deck hinders access to the hold (8). It would originally have stood against the front of the wheelhouse, with the two shorter legs bracing it against the wheelhouse roof. The wheelhouse was removed so that the engine could be stripped from the hull, leaving a big hole where the wheelhouse and engine used to be (9). Dropping down inside the vacated engine space, a generator is still mounted low on the starboard side. Behind the engine space, an intact section of cabin roof spans the hull, though leaving space for access forward and aft on the starboard side. Partitioned off at the port side is the perennial diver's favourite sight, a lavatory, with a small porthole to provide light and ventilation (10). The cabin forward of this lavatory on the port side was still intact when the Unity sank, but the outer wall and roof have now fallen outward and come to rest on the seabed. Behind the cabins, the spreaders for the trawl stand on either side, solid pillars with the tops canted out and pulley blocks hanging from the ends. The centre of the aft deck is marked by the outline from where the base of the trawl winch would have been bolted in place. The stern has sunk into the sand further than the bow, but the list to port leaves just enough space to get beneath the starboard side. As would be expected on a ship stripped prior to breaking, the propeller had been removed before the Unity sank. A little way forward, and the vent for the engine-cooling water is exposed just above the seabed. At the final point on our tour, although unlikely to be the end of the dive, a 10cm rope is tied to the starboard spreader and floats off for several metres before breaking. Already covered in big plumose anemones, I suspect that eventually the weight of accumulated silt and marine life will bring this down to the seabed. The Unity is only a small wreck, so even a no-stop dive will give time to swim the length of the wreck and back to the bow with plenty to spare. With no current to worry about, ascent is easy via the buoyline at the bow.

Guide to Avoiding Ear & Sinus Injuries in Scuba Diving

Learning to Adapt
As divers, we must adapt to an environment that exerts pressure on our bodies. The most common injuries reported to DAN each year involve pressure-related injuries to divers' ears and sinuses. A little education and common sense will go a long way to avoid these problems. Take a minute to read this page. DAN, your dive store and your instructor want your scuba adventures to be enjoyable and safe.
Sinus and Middle Ear Injuries
Barotrauma is a pressure-related injury. Middle ear barotrauma, known as "ear squeeze," is the most common diving injury. Sinus barotrauma also occurs, but is less common. How does it happen? Pressure changes when diving cause barotrauma. During descent, air spaces in the sinuses and middle ear must be able to equalize to the surrounding water pressure, which increases with depth. When pressure in air spaces can't equalize, the diver may sense pressure or pain from one of these areas. During ascent, if the expanding air can't be vented, the cavity pressure increases, resulting in discomfort. This type of injury can range in severity - from mild to extreme. A sinus or middle ear injury may occur suddenly and lead to inner ear damage. For this reason, divers should know and use the "clearing," or equalizing, maneuver that works best for them.
How to Equalize
The Valsalva Maneuver.
In what is probably the most commonly taught means of equalizing pressure during diving, divers close their mouths, pinches their noses and blow gently. Avoid blowing too hard and over-inflating the middle ear space. This can occur if divers are overly excited or having a difficult time equalizing during descent - and especially if they have waited too long before attempting to equalize. The result could be injury to the middle or inner ear.
The Frenzel Maneuver.
This method is similar to the Valsalva maneuver, except that instead of blowing air into the sinuses, the diver closes the nose and mouth, and drives the tongue backwards on the roof of the mouth. The muscle contraction opens the nasal cavities and eustachian tubes, which allows air into the middle ear.
The Yawn & Swallow.
Some divers can simply swallow, yawn or thrust their lower jaw forward and open their mouths while using their lips to maintain a seal with the regulator mouthpiece. This opens the eustachian tube to the middle ear, which equalizes pressure. As long as the sinuses also equalize easily, this maneuver is acceptable.
For many divers, a combination of these methods - even switching back and forth during a single descent - works best.
Prevention is the Key
The most common reason divers suffer barotrauma is a failure to inflate their ears and sinuses with additional air during descent. Often divers mistakenly wait to equalize their ears or sinuses when they feel discomfort. Begin the equalizing process by inflating your ears and sinuses with air before entering the water or beginning your descent - this ensures that the air passages are open and clearing is possible. A slow, steady descent with frequent inflation (every 1 to 2 feet) is then possible without barotrauma.
If you feel discomfort, stop your descent and ascend a few feet until the discomfort is relieved. Attempt to clear but do not continue your descent unless your sinuses and middle ear spaces have equalized.
Some divers may use topical nasal vasoconstrictors such as Afrin®, which may help with the process of equalizing when used before a dive. Regardless of the technique you use to equalize your ears and sinuses, remember to descend slowly until you can easily clear these air spaces.
To avoid barotrauma, remember:

• Test your ears and sinuses by equalizing prior to entering the water or prior to your descent; 
• Descend at a slow, steady pace and keep up with your clearing maneuvers; 
• Do not continue to descend and forcefully clear if you're having difficulty - stop your descent before you experience ear or sinus pain (waiting until you feel discomfort to begin clearing means you've waited too long); 
• Descend and equalize in a feet-first position; it is easier than head-first; 
• If you do experience pain or discomfort, ascend until it is relieved; 
• Equalize early and often to stay "ahead" of barotrauma. 

Difficulty Equalizing
What if you can't equalize? First, don't dive until the problem is resolved. If a diver has trouble equalizing the sinuses and middle ear, there may be some pre-existing problem - the most common is diving with a cold or flu. Frequently the mucous membrane will retain fluid and swell, partially occluding the air passages to your sinuses and the Eustachian tube going from the back of your throat to the middle ear. This not only makes clearing difficult, but it may prevent it altogether.
Other recognizable factors in equalizing problems are:

• a history of childhood ear infections or even one severe infection that may leave the eustachian tube scarred and partially occluded;  
• a history of a broken nose or a deviated septum that prevents one ear or set of sinuses from clearing as fast as the opposite side;  
• hay fever, which may produce swelling of the mucous membranes or cause nasal polyps that can partially or completely occlude a sinus cavity or airway.  

If you have a history that includes these conditions and want to dive successfully, it may require referral to an ear, nose and throat physician or allergy specialist who is familiar with these conditions.
Symptoms of Barotrauma
The most common barotrauma symptom a diver experiences may be mild discomfort to intense pain in the sinus or middle ear - this is usually the first indication of a problem in equalizing. Middle ear barotrauma may also include symptoms of ringing or hearing loss. As blood or fluid accumulates in the middle ear a diver may experience a partial, complete or muffled hearing loss as well as damage to the inner ear. Roaring in the ear, nausea, vomiting, dizziness, a sensation of spinning and decreased hearing may also indicate inner ear barotrauma, which requires urgent specialized treatment. Blood from the nose or in the sputum is also an indication of barotrauma and does not have to be associated with other symptoms. These are symptoms that should probably end the day's - and possibly the week's - diving. Continuing to dive with barotrauma may result in serious injury.
Treatment and Medication
If you experience any symptoms during or after a dive, then you should consult a physician to determine the extent of the injury, or if there is some treatable condition causing the problem. Your physician can determine the correct treatment and medication for sinus or middle ear barotrauma and refer you to an ear, nose and throat specialist if necessary. Proper care and medication under a physician's supervision can reduce the time divers experience barotrauma symptoms - and the sooner they can get back into the water to enjoy diving.

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