What You Need to Know About Currents
The thrill of flying over a reef, pushed onward by a strong current, can be one of the most exhilarating experiences in diving. But diving in currents can lead to problem situations if you’re not vigilant.
A number of factors cause currents, including the tides, wind, and thermally unstable water columns. Usually currents run horizontally, parallel to the earth’s surface — these are perfect for drift dives. Certain situations, however, cause currents to run vertically up (up currents) or down (down currents), while other currents can create a horizontal vortex. If a diver gets caught in one of these currents it can quickly lead to a dangerous situation. Down Currents
A down current occurs when a current hits the face of a wall or when it runs at a right angle to a drop off. Down currents are also possible when two currents moving in opposite directions meet or move over each other. These types of currents have a nasty reputation among divers, and for good reason: they can quickly drag you far deeper than your planned depth. Sometimes this occurs gradually, and you won’t realize it until you feel the need to equalize, or until you look at your depth gauge or dive computer. But in some situations, a down current can pull you from 15 feet to 65 in a few seconds.
Most down currents lose strength the deeper they go, but don’t just wait for the ride to end, though, as there’s no telling how deep the current will take you. If you get caught in a down current, try to remain calm. Stop. Think. And then act. Maintain natural breathing to conserve air, and swim out into the blue. Although you may be in a scary situation, remember that down currents generally become weaker further away from the wall or drop off. While you’re swimming out, you also want to swim up — aim to swim a 45-degree angle.
If the current is especially strong you may want to inflate your BCD, but remember, an inflated BCD creates a larger surface area for the current to push against, so it might not help as much as you think. If you do inflate your BCD, prepare to deflate it rapidly once you’re out of the current to avoid a run-away ascent. Avoid dropping your weights unless you absolutely must.
Another option is to get as close to the wall as you can and climb up. The current is likely to be strongest here, and you might need to hold on to the coral to pull yourself up. If you must use this option, do so with caution and try to keep yourself and the coral as safe as possible. Try to hold on to dead coral and avoid stinging hydroids. Up Current
As with down currents, up currents can occur when a current hits the face of a wall. These are dangerous because they can pull you up to the surface very quickly, which can lead to a host of problems, including decompression sickness, a lung over-expansion injury or arterial gas embolism. Try to maintain the same calm as with a down current, and react similarly by swimming away from the wall or drop off into the blue. Deflate your BCD and swim down. Washing Machine
A washing-machine current occurs when the bottom typography bounces currents around. These types of currents can push you in all directions, creating a feeling of extreme disorientation, which can be amplified when your bubbles get swirled around, making it very difficult to tell which way is up. As with up and down currents, try to swim out of the current horizontally while swimming slightly against the push of the water to avoid drastic changes in your depth. Vortex
Very little information is available about vortex currents as they only occur at a few dive sites around the world. The best way to deal with this kind of current is to avoid getting caught in it all together. If you do get caught in one, try to conserve as much energy as you can, wait until you feel it weakening slightly and swim perpendicularly out of it. This video
of Socorro shows how easily a diver can get caught in a vortex. Note the horizontal snake of bubbles that acts as an early warning that this kind of current is present. How Do You Recognize Types of Currents?
You can often predict strong currents, horizontal or vertical, by looking at the surface of the water. Areas where the surface is choppy without a moderate to strong wind, mixed with areas of very smooth water, could indicate a strong current. If the boat that you’re diving from is tied to a mooring buoy, look at the direction in which the boat is turned. If the boat is tied off at the bow, the boat will be facing into the current; if the mooring line is tight, the current is likely moderate to strong.
Underwater you can tell which way the current is running by observing the sea life around you. Soft coral sways in the direction the current is traveling, and fish face into the current, so if you see a school of fish pointing in one direction, that’s where the current is coming from. If a school of smaller fish is swimming around freely in different directions, there’s probably only a slight current, if any at all.
Bubbles can also tell you a lot about the current. Strong down currents can sweep your bubbles into the depths, as can horizontal currents. One of the only ways to identify a vortex is by its distinctive, serpent-like horizontal river of swirling bubbles.
Current diving can be exhilarating and safe if you stay vigilant and practice good judgment. Learn to recognize different types of currents, and be prepared. If you’re diving in an area known to have currents, always carry a DSMB, or safety sausage, in case you get separated from your group and must surface alone. As with any dive, if you feel uncomfortable or find the currents too challenging, better to abort your dive and move to a site with more favorable conditions.
OSLOB WHALE SHARKS
By Atilla Kaszo
Whale sharks originated about 60 million years ago, and today, they are listed internationally as a vulnerable species, but still commercially targeted in some Asian countries. Fortunately, not all Asian countries hold the same harvesting view, and many fishing communities have turned to tourism as the main source of income.
Donsol and Oslob in the Philippines are such examples. Whale sharks had been visiting these regions for decades and during those decades were hunted. In 1998 at Donsol, they were apparently “discovered” and after international support hunting turned into whale shark watching which turned into eco tourism. Oslob went much the same way but later in 2006.There appears to be some controversy and confusion regarding the Oslob site, in that feeding the whale sharks by the locals has somehow upset the ecosystem and accordingly drawn criticism from some quarters.
Clearly, feeding any wild animal is not something that should be encouraged, but given the relatively small amounts of fish “burley” that is put into the water and the area in which these sharks are being fed poses little impact on the regions biodiversity. More important to the animal’s welfare is the extent of physical human contact with these giants. As human nature has it, people get a bit excited when a 14-meter fish swims past, so the impulse to touch it and grab that Kodak moment seems to prevail over common sense. There is certainly a case in keeping people at a “safe” distance, and I would completely support such action.
On the flip side however, whale sharks like most wild creatures have the ability to leave the area or move away from a hazard almost instantly. So if the shark wants to it does just that, as do whales I have worked with and so on. In fact some of my best work has been outside the “viewing areas” where the sharks had left the feeding zones and were swimming about 200 meters away and in a blink almost on top of me having a close up and personal and then gently swimming away.
Before I went to Oslob, I read a number of petitions against visiting the area, mainly for the reasons I have outlined, and that some reports indicated that the sharks had severe rub marks on their necks, apparently from trying to get into the boats carrying food, and other reports suggesting that the sharks had deep cuts and abrasions over their bodies from boats crashing into them. I saw none of this at all. The only cut I saw on a shark was on it’s back and it could well have been an outboard propeller, I don’t know. All the sharks I saw, about thirteen, looked very healthy and active, and had no problem swimming away from people in the water.
My research also indicated that the sharks at Oslob were transient and that different individuals moved through the region during the year. Unfortunately there is still relatively little known about these sharks, which makes management of them difficult. Nonetheless, erring on the side of caution may be the prudent way to go, along with considering the needs of the locals who depend on some form of income for their survival. From my perspective, it’s a better option to accept how the village manages its resources now than to entertain the harvesting practices of the past.
The Proper Scuba Dive Weighting
Guidelines for Proper Weighting. We all know that most new divers tend to need a bit more weight than seasoned ones because Buoyancy Control takes several dives to master. Common types of weights include pouchstyle with lead pellets (left) or solid lead style.
Here is the best rule of thumb for weighting:
Swimsuit or DiveSkin- Begin with 1 to 4 pounds / 0.5/2kg
Thin 3mm wetsuits or Shorty- 5% of your Body Weight
Medium Thickness 5mm suits- 10% of your Body Weight
Cold Water 7mm with hood/gloves- 10% of your Body Weight plus 3-5 pounds / 1.5/3kg
Neoprene Drysuit- 10% of your Body Weight plus 7-10 pounds / 3-5kg
Shell Style Dry Suits w/o under garment – 10% of your Body Weight plus 3-5 pounds / 1.5/3kg
Shell Style Dry Suits w/ heavy under garment – 10% of your Body Weight plus 7-14 pounds / 3-7kg
The undergarments vary quite a bit as they can realy add allot surface area to you thus increasing the amount of weight needed to stay neutrally buoyant.
Salt Water Diving (add to above calculations for Fresh Water)
100 to 125 lb (45-56kg) add 4 pounds (2kg)
126 to 155 lb (57-70kg) add 5 pounds (2.3kg)
156 to 186 lb (71-85kg) add 6 pounds (3kg)
187 to 217 lb (86-99kg) add 7 pounds (3.2kg)
Always do a buoyancy check before beginning your dive and also factor in that if you are diving with an aluminum 80 tank you will need to add a little more to compesate for the tank toward the end of the dive. If you are diving with a steel tank the same holds true except you will need less weight. That is why it is so important to perform a neutral buoyancy check before beginning your dive.
The Importance of Dive Tables
By Thomas Gronfeldt
With inexpensive dive computers on every wrist these days, do we even need dive tables anymore? Yes, in fact, we do.
There was a time when dive computers were for the few, the most dedicated or simply the most flush with cash. The sheer cost of a dive computer meant that most divers went without one, relying instead on a waterproof watch and an analog depth gauge. These were the days of dive planning and dive tables. Before a dive, divers would plan the maximum depth of the dive, which was not to be exceeded, and a maximum time for the dive based on the data their dive tables gave them. Once the dive was completed, the nitrogen load of the dive would be calculated using the table. And based on this, the timing, depth, and duration of the next dive could be planned.
But as Morse’s Law came into effect (any new technology will double its processing power and halve its price roughly every 18 months), dive computers have become accessible for every diver who wants one. Small, inexpensive and all very capable of giving you dive time, depth, remaining dive time and surface time between dives, computers have become for many divers a key piece of gear. I use one myself. And several organizations either have or are considering making the switch completely to the point where dive computers are taught during dive classes and dive tables are left completely out of the equation.
The reasons given in support of this policy are quite good: dive computers are everywhere and inexpensive enough that any diver can afford one, they allow for longer dives due to their on-going calculations of nitrogen loads (rather than calculating the diver as having spent the entire dive at the maximum logged depth, as the tables do), they’re reliable, safe and much easier to learn how to use for a new diver than the dive table and its principles are. So from one perspective, safety would be enhanced by using computers instead of tables.
But we should be cautious about throwing the baby out with the bathwater. Having access to dive computers is great, and it’s a great safety asset for divers, but that shouldn’t mean we completely discard dive tables. Why? There are a number of reasons:
1. Dive tables are universal
. Dive computers are all slightly different from one another, both in design, user interface and in the algorithm that calculates dive times (hence the warning never to do to consecutive dives on different computers). A dive table is not this way. If you find yourself without a dive computer, the table can always take over. And by making sure all divers are able to plan a dive according to a dive table, there will be no confusion over which computer’s data is used.
2. Dive tables don’t crap out
. Yes, dive computers are safe and reliable. But they’re not 100 percent reliable. I have seen dive computers crap out during dives and on diving holidays, and I’ve had it happen to me. The normal advice when this happens is simple: stop diving for 24 hours to allow complete nitrogen degassing. However, if you’ve logged all your dives using a dive table you’re able to continue diving (after ending the dive at the moment the computer dies, of course) using any means of depth and time measuring available. That could be a backup computer in gauge mode, watch and depth gauge or a watch with a built-in depth gauge. Some of the more experienced divers out there will even make a note - mental or on a writing slate - of the time allowed at the maximum depth of their planned dive, just in case. If you have not kept a continuing log for all your repetitive dives and all you have is the dive computer’s log, there’s no other option than to abstain from diving for a full 24 hours should your computer fail.
3. Dive tables prepare divers for more advanced planning
. As divers progress in skills and experience, they may start learning how to dive with more advanced gasses in their tanks. And part of knowing how to dive with Nitrox, Helitrox or Trimix is the ability to do depth and dive time calculations based on dive tables - tables that are somewhat more complex than the ones used for diving on normal air, to boot. Knowing how to use the basic tables prepares you for learning how to use the advanced ones. And it doesn’t look like the requirement to be able to plan and calculate your dive and gas needs will go away from Nitrox courses or tec diving courses anytime soon.
4. Dive tables are good practice
. For many divers I’ve observed, it isn’t until they log their dives that the reality of nitrogen load really dawns on them. Working their way up the letters indicating nitrogen load is a very tangible way of experiencing that for each dive they came closer to their body’s maximum capacity for dispelling nitrogen. A dive computer doesn’t have the same effect on most people - there’s something too abstract about the digital numbers. So, in particular for new divers, it’s a good learning experience to work with tables.
The bottom line is that I believe dive computers have, in fact, made diving safer. But just like ABS braking systems and anti-skid systems in cars shouldn’t make us lazy drivers and unable to stay safe without them, dive computers should never take the place of the diver’s brain. Use them as an additional layer of planning and safety, but don’t let them replace sound judgment, good planning and reasonable conservatism. And dive tables – don’t forget the dive tables.
What You Should Never Do on a Dive
The golden rules of what NOT to do while scuba diving. Use common sense & scuba training to have fun and stay safe.
Never Not Have A Plan
Do your research. Plan your dive & dive your plan. Agree with your buddy on depth, time, safety stops & minimum air before you head to the exit point. Check your equipment! Don't Be Sick
Including hangovers. You'll want as much energy as possible to dive & you'll want to stay hydrated. Eat at least 2 hours before hand & drink plenty of water. Take sea sickness pills to build immunity. Do Not Go Outside Your Comfort Level
This isn't some reverse psychology ploy. If you feel uncomfortable diving that deep, DON'T DO IT. Stay within your comfort level, skill & training. Otherwise, you could panic and get hurt. Never Hold Your Breath
When you descend the pressure on your lungs increases & your lung volume decreases, it's the opposite for ascending. A diver who holds his breath underwater seals off his lungs, severely hurting them. Never Go Alone
Use the buddy system; one person below, one above and yourself. It can be incredibly dangerous (and difficult) to dive by yourself. If you are certified, bring another certified friend. Don't Buddy Breath
Unless you and a buddy have practiced breathing from a single regulator, do not do it. Typically, one of you will forget to control your buoyancy. Proceed with Bad Weather
Ask around about weather & conditions the morning of. Err on the side of caution: if it's too rough and it could lead to a dangerous situation, don't go.
The Benefits of Diving
By Jessica Shilling
For some it´s the adrenaline rush of the exploring the deep waters, for others it´s the beauty of the reef and the marine life that inhabits it. There are many reasons to scuba dive but most would agree that they dive for the pure enjoyment of experiencing the underwater world, so different from ours and truly amazing.
Scuba diving has it all, it’s an fantastic experience that can improve your emotional and physical health while learning new skills, making friends and expanding your environmental awareness.
Just starting out? Take a look at the following list of benefits for a little encouragement.
You don't have to be incredibly fit to scuba dive. It's a sport that's easily accessible to the average person. You do however need to be in a state of good health and free of any serious medical problems. Before diving you will be asked to answer a medical questionnaire and if your instructor has any concerns you will be referred to a doctor for a check-up.
If you dive on a regular basis your general fitness will improve. Exercising in water is an excellent way to strengthen your muscles. You spend hours in the water carrying heavy equipment while swimming against the natural resistance of the water. This may sound very tiring but it feels effortless because you are too busy enjoying yourself but in reality you are getting a fantastic work out.
Gliding underwater while watching the fish go by is incredibly relaxing. Many people find diving to be a great way to get back to nature and de-stress. With practice you will learn calming breathing techniques which will not only make the dive more enjoyable but you´ll use up less air and be able to stay underwater for longer. Once you master your buoyancy it will make your diving experiences even better, it will become even more relaxing and you will feel one with the water.
One great thing about diving is meeting fellow divers. By joining a scuba diving class or club you'll immediately come in contact with a lot of people with the same hobbies who may become life-long friends. While on a dive trip its common to make friends with fellow divers on the dive boat making your vacation even more exciting.
Diving makes you appreciate the ocean even more and will bring you in contact with people that can educate you about fragile underwater habitats and the importance of preserving them. You can even join ocean advocacy groups like the Making Waves in Colorado event and volunteer to help protect marine environments.
Join the 3rd annual Making WAVES in Boulder, Colorado on September 20th to the 22nd where you´ll have the chance to enjoy insightful presentations on ocean advocacy and more from an exciting list of attendees. This multifaceted symposium and celebration highlights ocean issues, solutions and is a change making event for engagement and national action.
How to Gear up your Scuba Kit Quickly, Easily and Efficiently?
Posted by Rutger Thole
How often have you seen someone dance around in circles trying to grip their wetsuit zipper or even spotted people walking into the water like frogs because they already have their fins on, or seen their masks fly off into the air as they tried to put it on?
All of this is a complete waste of time and an unnecessary one at that. If you know how to gear up quickly, easily and efficiently, you will have far more time to enjoy diving as well.
Organizing Your Scuba Gear
Always make sure that your scuba gear is organized. If everything is in its place, you will be able to get things on much quicker as well, as you won’t have to waste time trying to find your belongings.
Not just that, you will always be aware of the condition your gear is in, enabling you to replace it as and when necessary.
Make sure, of course, that you look after your gear, drying it off before storing it and keeping it somewhere dry and safe from the elements.
Bring a Plastic Carrier Bag
How hard is it to get your hands and feet into a wetsuit? Although once on, they are incredibly comfortable, getting the suit on can be an absolute nightmare.
Interestingly, a simple plastic bag can help you with this. It goes without saying this plastic bag should be stowed away properly so it will not end up in the water. Have you ever heard of the great pacific garbage patch?
You may be tempted to use lotions to make your skin more slippery, but this can actually be damaging to your suit whereas a plastic bag does not.
Simple put it over your hand, feet, or whatever it is that you are trying to get through and you will notice it slips on and fits like a glove straight away.
Always Help Your Fellow Divers
If you see that someone else is struggling or looks like they don’t know what to do, go help them out. Just share your knowledge, including the above two points, and you will make sure they can enjoy their time a lot better as well.
Remember that scuba diving is something that you do together, which is why it operates according to a buddy system.
You are not competing to be in the water first or to have your gear on first. If you have any knowledge you can impart on less experienced divers, then make sure you do so.
This will also show them that divers look after each other and that it is ok to ask questions.
Scuba diving is fun and should be a relaxing hobby. This means that there is no time or energy to waste by things such as struggling to get your gear on.
Look, But Please Don’t Touch
Seeing marine life in its natural environment is one of things that attracts people to scuba diving. Unfortunately, some divers seem to have forgotten the section of their PADI Open Water class where the instructor taught them not to touch or hassle marine life. As a gentle reminder, here are some of the consequences of not being kind to underwater creatures.
Curiosity killed the coral. Coral is beautiful, but resist the urge to touch it. When you touch coral it will be harmful to it and can even kill it. A human touch is like a poison and its results may not show until months later.
Watch where you swim! Your fins can create a small wave that will disrupt the layers of sediment below. This reduces coral’s photosynthetic abilities and washes away small animals, which increases their chances of predation. Breaking off just a small piece of coral can do damage that will not repair itself within your lifetime.
Remember to secure all of your dive equipment. If something touches a fish it can remove their protective coatings, leaving them vulnerable to diseases.
Puffer fish are particularly susceptible to harm by humans. Some divers choose to agitate the fish in order to make it puff up. To create this effect, the fish fill themselves up with water or air and “puff-up” their prickly bodies. Sadly, they only have a small number of puffs in their life because it’s hard on their internal systems to inflate regularly. Repeated puffs can significantly shorten the poor fish’s life.
Don’t feed the fish. Many fish are unable to digest human food, which causes them internal damage that can end their life. Remember, no one likes food poisoning.
9 Reasons Why Regulators Leak
by John Francis
|Common Regulator Leaks.
The leak - First stage.
Where - From orifices and seams in the first stage housing.
Looks like - Anything from an occasional bubble to a constant small stream.
The problem - Wear and tear, or misadjustment of the internal parts during overhaul.
The fix - Requires a technician.
Abort the dive? - Judgment call. It's not likely to get worse quickly, and an occasional bubble might be tolerable for the day. If leakage increases, head for the surface.
The leak - Sherwood first stage bleed.
Where - From a single orifice of a Sherwood first stage.
Looks like - A steady stream of very tiny bubbles.
The problem - None. The bleed is intentional, a design feature of the dry piston-type first stage.
The fix - Put your wrench away. Please!
Abort the dive? - Read my lips: there's nothing wrong. The air loss, by the way, is minuscule—less than one breath in an hour.
The leak - Regulator yoke.
Where - Between the tank valve and the high-pressure valve seat at the yoke.
Looks like - Anything from an occasional bubble to a constant stream.
Sounds like - Bubbling from almost-flat soft drink to a boiling kettle.
The problem - The O-ring is dirty, cracked, worn, dry or the wrong size. Or the seat is nicked or dirty. Or the yoke is loose or not positioned correctly. Some DIN-to-yoke adapters make alignment of the yoke difficult.
The fix - Remove the O-ring, clean and inspect the seat. Replace the O-ring with a new one, coated with just enough silicone to make it supple, not greasy. Tighten the yoke by hand, but firmly. No luck? Try a different tank.
Abort the dive? - Judgment call if the leak is very small, but it's better to return to the surface and replace the O-ring.
The leak - Tank O-ring.
Where - Between the tank valve and the high-pressure valve seat at the regulator yoke.
Looks like - Other divers leap backward like they've seen a cobra.
Sounds like - A Boeing 727 on thrust reversers.
The problem - This usually happens when you first turn on the air, if you haven't tightened the yoke enough. With the seat loose, pressure forces the O-ring to squeeze through the gap and tear, causing a loud escape of air. Another cause is using the wrong-size O-ring.
The fix - A new O-ring and a stronger hand on the yoke screw.
Abort the dive? - Only until you calm down.
The leak - Hose O-rings.
Where - At either end of any hose, between hose end fitting and whatever it screws into (first stage, second stage, BC inflator, SPG, etc.).
Looks like - Anything from isolated bubbles to a constant stream.
Sounds like - Nothing, or a faint hiss.
The problem - The O-ring is dirty, cracked, worn, etc., as above. A leak immediately after an overhaul probably means the tech has not tightened the hose enough. If very loose, the O-ring can blow out with sound effects as above.
The fix - Also as above. Where there is a swivel on the hose, be sure to separate between the swivel nut and the next nut, not between the two nuts and the SPG or second stage. How much to tighten the hose? One ungh on a short wrench.
Abort the dive? - If it's the high-pressure hose to the SPG, it will be a small leak. As long as it doesn't seem to affect the gauge, you can probably continue the dive. The high-pressure hose leak looks dramatic but involves very little air—the orifices are tiny. A low-pressure hose actually leaks more air, but you will still have time to return to the surface calmly and deal with it.
The leak - Worn hose.
Where - Anywhere on any hose, but usually near the first-stage end fitting.
Looks like - A tiny bubble, or chain of tiny bubbles on the surface of the hose. Or a steady stream of bubbles.
Sounds like - Maybe nothing, maybe the fizz of ginger ale.
The problem - The inner, woven layer of the hose has developed a weak area, usually through constant flexing. Air leaks to the outer, scuff-protecting layer of the hose, which has a chain of tiny relief holes along its length. That's where the bubbles come out.
The fix - Replace the hose. High-pressure and low-pressure hoses are not interchangeable, nor are low-pressure regulator and inflator hoses, though the industry is moving in that direction.
Abort the dive? - As with hose O-rings: The high-pressure hose is a judgment call, depending on how serious the leak is. Surface to replace a low-pressure hose.
The leak - Second stage, due to excess intermediate pressure.
Where - From second stage exhaust.
Looks like - Anything from a bubble every few seconds to a constant stream.
Sounds like - Anything from a slow "glub, glub, glub," to a pot at full boil.
The problem - Several possibilities, same symptoms: (1) first stage out of adjustment and delivering too much pressure; (2) second stage "cracking pressure" too low.
The fix - Dial back the second stage adjustment (if you have one) for more breathing resistance until the leak goes away. If you have to dial it back again and again as the dive continues, this is a sign of first-stage problems. By the way, flipping the minimum/maximum or venturi switch will have no effect. Have your reg serviced at the first opportunity.
Abort the dive? - if you can keep the leaking under control by adjusting the second stage. But if the problem is getting worse, head for the surface.
The leak - Second stage, leaking valve seat.
Where - From second stage exhaust.
Looks like - Same as excess pressure leak, above.
Sounds like - Same as excess pressure leak, above.
The problem - Sand, grit or corrosion under the second stage valve seat prevents it from sealing.
The fix - Swirl the second stage through the water while working the purge (tank pressure must be on). The sand or grit may be washed out. Back on the boat, you may be able to remove the purge cover for better cleaning. Just be absolutely sure to put all parts back in the same order. If it's a corroded seat, only a technician can make the repair.
Abort the dive? - Swirling may reduce the leak to manageable proportions. Otherwise, make a calm, normal ascent; air is not disappearing as fast as it sounds (though watch your SPG).
The leak - SPG spool.
Where - Between the swivel fitting and the body of the submersible pressure gauge.
Looks like - Anything from a steady stream of bubbles to a constant fizz.
Sounds like - Anything from a boiling tea kettle to a roaring jet engine.
The problem - The spool is the hollow stud on which the swivel mechanism mounts. Banging and dragging the SPG can bend or break the spool, or distort its O-rings.
The fix - Requires some technical knowledge, but take heart: many dive boat captains, resort operators and dive shop folks can do it.
Abort the dive? - As with all high-pressure hose leaks, it looks and sounds worse than it is because the pressure is high but the volume is low. As long as the SPG is reading correctly it is a judgment call.
Diving With Less Than 20/20 Vision
By Jessica Vyvyan-Robinson
For those whose eyesight requires corrective measures, the prospect of diving — a primarily visual pastime — can be a little daunting. Proper diver safety also relies on keeping a keen eye on your buddy, your location and your gauges. But a lack of 20/20 vision is by no means a barrier to diving, as there are many options available to facilitate participation despite all manner of sight issues. Many people with mild vision impairment don’t need to take any corrective action, as objects in water are naturally magnified by 33 percent. But if corrective measures are needed, there are several methods of compensating for sight problems underwater, making for safer, more enjoyable dives.
One of the simplest ways to deal with poor eyesight is to wear contact lenses, just as you would on land. Certain precautions should be taken to minimize eye irritation and to prevent losing the contacts, but generally, diving with contacts is a safe and hassle-free solution. The Diver’s Alert Network (DAN) recommends using soft contact lenses for scuba rather than hard or gas-permeable ones, however, because increased pressure may cause hard lenses to suction to the eye, causing pain or discomfort. Hard lenses typically dry wearers’ eyes out more, too, resulting in redness and irritation upon surfacing. Most importantly, soft lenses allow the nitrogen absorbed by the eye while diving to escape; hard lenses do not. Bubbles can form between the hard lens and the eye, causing blurred vision, which effectively negates the purpose of wearing the contacts in the first place.
Wearing contact lenses underwater also means keeping the eyes closed when performing any skills that require the flooding or removal of the mask. If you are enrolling in a scuba course, be sure to tell your instructor if you wear contacts so that he or she will allow you to keep your eyes closed during skills, and to wear a mask during surface water skills or swim tests. Similarly, if you’re using vision-correcting equipment, from contacts to prescription masks, make sure to alert your buddy: if you should lose your mask underwater, they need to know that they’ll need to help you find it. In terms of comfort, even soft contact lens wearers often report some dryness as a result of diving; it’s a good idea to bring lubricating drops with you to the site for use before and after diving. Rinsing lenses in fresh saline solution between dives can also minimize irritation from residual salt water; divers should consider using disposable contacts for live-aboard trips so that they can use fresh ones each day.
There are alternatives to wearing contacts while diving for those who are squeamish about using them or simply prefer not to. Depending on the severity and type of eyesight issues, the lenses of some stock masks can be quickly and easily replaced with pre-made corrective lenses. For those with astigmatism or other, more extreme vision impairment, pre-made lenses may not work sufficiently. Custom-made prescription masks are also an option, wherein a mask is made specifically to your requirements. Those who opt for prescription masks should consider purchasing two customized masks in case of loss or damage to one of them, as it can be exceptionally hard to find a replacement in many of the world’s remote dive destinations.
The most permanent alternative is corrective eye surgery, but it is imperative to consult an ophthalmologist before your first dive, after surgery, in order to respect the healing period. If not properly observed, the effects of pressure and trapped gas on an unhealed incision could be incredibly painful.
The final option, particularly for those who require bifocals, is adhesive magnifying patches, which are applied to a stock mask lens and can be purchased at most large dive equipment stores or an optician’s office.
For most people, however, contact lenses are the simplest choice for correcting eyesight while diving. They are cost-effective, and divers are able to wear them both while kitting up and during the dive. Whatever your preference, there are plentiful corrective options available to ensure that everyone can experience the beauty and wonder of the underwater world.