Wednesday, June 30, 2010

How Deep Can I Dive????

The BlueImage by Dude Crush via Flickr

One of the most common questions asked to Scuba Divers is, "how deep can you dive?" Well, there's no easy answer to that question because it depends on a lot of factors. For the sake of argument, we're going to discuss how deep you can dive with standard scuba equipment.

How Deep Can I Go With Standard Scuba Equipment?

Firstly, a little disclaimer: Just because you can go a certain depth does certainly not mean it is safe, especially if you do not have the appropriate training and experience for that depth.

With standard scuba equipment you have a maximum depth of approximately 60m (195ft). This is because, after this depth the pressure exerted on the oxygen in your air supply becomes toxic, going further or experiencing this toxicity for too long could prove fatal. At depths between 30-60m, while not dangerous in itself, is likely to bring on the onset of nitrogen narcosis which can have a severe impact on a diver's decision making, leading to stupid and sometimes dangerous actions.

As we mentioned, oxygen at higher partial pressures (1.44bar to be exact) become toxic. Aside from this, the diver must also be aware since their air is getting compressed, it will provide fewer "breaths" and will of course, run out a lot quicker than if he or she were diving at a shallower depth.

PADI recommend that the absolute maximum depth for a recreational diver is 40m (130ft), while BSAC recommend a maximum depth of 50m (165ft) with proper training.

Is Diving Deep Important?

The short answer to this is, no - diving deep is not important for the recreational diver most of the time. The shallower you are, the more bottom time you'll have and the less you'll have to worry about - a more pleasant experience for all.

Keep in mind the "mission" of your dive when you plan it. There's a lot of things to see at depths less than 40m (130ft). It maybe be necessary though, if a diver is specifically doing a recovery dive or viewing a wreck that they just didn't damn sink at a sensible depth to go deeper. In these cases it is important that you are well versed with your scuba gear, the effects of nitrogen narcosis and know you your limits in terms of experience and ability and of course, of your buddy too.

So How Deep Can You Go With Specialist Equipment?

There are specialised pieces of scuba diving equipment that make it possible to overcome deep diving problems such as nitrogen narcosis, oxygen toxicity and the tremendous pressure you can face at extreme depths.

It is possible to technical divers to go as deeper than 200m (700ft) with closed circuit rebreathers. As we discussed earlier, oxygen at high pressures becomes toxic, so these divers also use mixed gas, the usual mix is helium and oxygen, which eliminates the nitrogen narcosis problem, but does leave you sounding like tweety bird when you talk!

Commercial divers, can operate at these depths (200m/700ft+), for incredibly long periods of time. They will typically work 6-7 hours per day, but stay under the water for up to a month at a time! Rather than waste time decompressing, these guys essentially "live" in compression chambers while they're not diving. These compressors can be on a ship, or in some cases, sunken to be near the dive site.

Thanks to the Scuba Site for this article.

Kathy Dowsett

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Saturday, June 26, 2010

How fit do you have to be to scuba dive?

SCUBA divingImage via Wikipedia

The answer to the first question is easy, you don't have to be an athlete to scuba dive, as when done properly, under normal circumstances, it is actually quite a relaxing sport. You'll be given (an above water) swimming test of 100m unaided or 200m with fins and have to tread water for 10minutes. Assuming you can do this, you're fit enough to dive!

Fitness and health are two totally different things and as scuba diving statistics show, most accidents are caused by underlying health issues.

Health is also a very personal thing - you cannot make assumptions that because someone else can dive with a specific health condition that you can (or cannot).

There are a standard set of questions which most dive operators will get you to answer before going scuba diving. Not all of the below conditions exclude you from diving, but it will give you a guide for the kind of things you are looking out for.

Scuba Diving Health Questions

Could you be pregnant or are you attempting to become pregnant?

Do you regularly take prescription or non-prescription medications? (with the exception of birth control)

Are you over 45 years of age and have one or more of the following:

a) currently smoke a pipe, cigars or cigarettes?

b) have a high cholesterol level?

c) have a family history of heart attacks or strokes?

Have you ever had or do you currently have...

Asthma, or wheezing with breathing, or wheezing with exercise?

Frequent or severe attacks of hay fever or allergy?

Frequent colds, sinusitis or bronchitis?

Any form of lung disease?

Pneumothorax (collapsed lung?)

History of chest surgery?

Claustrophobia or agoraphobia (fear of closed or open spaces)?

Behavioral health problems?

Epilepsy, seizures, convulsions or do you take medications to prevent them?

Recurring migraine headaches or do you take medications to prevent them?

History of blackouts or fainting (full or partial loss of consciousness)?

Do you frequently suffer from motion sickness (seasick, carsick, etc.?)

History of diving accidents or decompression sickness?

History of recurrent back problems?

History of back surgery?

History of diabetes?

History of back, arm or leg problems following surgery, injury or fracture?

Inability to perform moderate exercise (example: walking one mile within 12 minutes)?

History or high blood pressure or do you take medication to control blood pressure?

History of any heart disease?

History of heart attacks?

Angina or heart surgery or blood vessel surgery?

History of ear or sinus surgery?

History of ear disease, hearing loss or problems with balance?

History of problems equalizing (popping) ears with airplane or mountain travel?

History of bleeding or other blood disorders?

History of any type of hernia?

History of ulcers or ulcer surgery?

History of colostomy?

History of drug or alcohol abuse?

Am I healthy enough to scuba dive?

Unfortunately, it's not something you can find out online. The only way to be sure is to have a health check up by a dive doctor, which is different from your standard doctor.

Kathy Dowsett

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Tuesday, June 22, 2010

Prevent Foggy Masks

A foggy mask ruins an entire dive. Fog blocks a diver's view of the incredible underwater world and impedes communication between divers. Fog can be dangerous. A diver distracted by a foggy mask can lose track of his buoyancy or his surroundings. It is possible to prevent any mask from fogging. However, new masks and used masks must be treated in different ways.

New Scuba Diving Masks:

New scuba diving masks
have residue left over from the manufacturing process coating the lens. Unless this coating is removed from the inside of the lens, the mask will constantly fog up no matter how much defogging agent is used. There are two good ways to remove the residue.

1. The Toothpaste Trick: Squirt toothpaste on the inside of the lens and rub it around with your finger or a soft cloth for a few minutes. The simpler the toothpaste, the better, so try to find a paste without bleaching agents and confetti. It may help to leave toothpaste in the mask overnight or to scrub the mask several times to allow the chemicals to react. Avoid using an extremely abrasive toothpaste or rough cloth, as these can scratch the inside of the glass.

2. The Flame Trick: Run the tip of a flame over the inside of the lens until the glass turns black, the flame will burn the residue off. A lighter or a tapered candle works well. Once the inside of the mask lens is totally black, wait for the mask to cool and wipe away the soot with a soft cloth. Repeat this process two or three times until it is difficult to get the glass to turn black. Do not allow the glass to become extremely hot, and do not attempt this trick on masks with plastic lenses (they will melt). Be sure to keep the flame away from the soft silicon skirt of the mask as it will melt with very little heat.

Used Scuba Diving Masks:

Masks should be treated with a defogging agent before every dive. If treatment with a defogging agent does not prevent the mask from fogging, it is possible that some residue is left over from the manufacturing process. Try the toothpaste or flame tricks to remove the remaining residue.

Any agent that prevents condensation from adhering to the inside of the mask's glass will keep the mask from fogging. See why defogging agents work. There are numerous options:

1. Spit: Spit on the inside of the mask and rub it around with your finger. Dunk the mask briefly in fresh water. The goal is to leave thin layer of saliva on the inside of the glass. Spitting does not work well if the mask dries out before diving, so use this technique immediately before the dive.

2. Commercial Defogging Agents: Commercial defogging agents are specifically designed to coat a mask's lens, and many divers find these products more effective than spit. Put a few drops of the defogging liquid in the mask, rub it around with a finger, and rinse briefly with fresh water. Remember, the idea is to leave a thin layer of the defogging agent inside the mask, so do not rub out the defog when rinsing the mask.

3. Baby Shampoo: Baby shampoo can be used just like commercial defogging solution. Many divers carry a bottle of watered-down baby shampoo with their dive gear. A few drops rubbed into the lens and then briefly rinsed out will keep a mask from fogging. Baby shampoo is preferable to standard shampoo, as it is generally hypo-allergenic, less irritating to eyes, and biodegradable. Baby shampoo smells good, too.

4. Glycerin Soaps and Dish Washing Detergents: Glycerin soaps and dish washing detergents can be used the same way as baby shampoo. Put a few drops on the inside of the mask, rub them in, and rinse briefly. If a mask leaks, it is possible that the water will carry whatever defogging agent is used into the diver's eyes. The one problem with these products is that they really burn the eyes. Glycerin soap and dish washing detergents sometimes are not biodegradable. Be sure to not dump any non-biodegradable defogging agents into the water.

5. Toothpaste: Rub a non-abrasive toothpaste on the inside of the mask lens until it coats the glass completely. Rinse the mask gently with fresh water until the lens is clear. If a diver is highly sensitive to minty fragrances, the air inside the mask may burn his eyes or cheeks during the dive. Before diving for the first time after using toothpaste as a defogging agent, wear the mask for a few minutes to make sure the fragrance is not irritating.

6. Potatoes: A cut potato rubbed on the inside of a mask lens has been said to keep a mask from fogging. Rub the potato on the glass, rinse briefly, and dive. This method is a bit of a diving urban legend, but feel free to test it out the next time there is a potato and a knife handy before the dive.

Thanks to Diving

Kathy Dowsett

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Monday, June 21, 2010

Free Diver Jana Strain Named 2010 World Champion

At the Mediterranean World Cup Jana Strain earned the title of individual world champion. Tension was high on the final day of the competition as the top women had their final dive determining who would take home the gold medal. Jana Strain finished the competition with a strong dive to 64M (210ft) with a fin (CWT).

Her other winning dives were 49M (161ft) no fins (CNF) and a 60M (197 ft) free immersion (FIM). The competition was exciting; many athletes’ preformed personal bests and broke records.

“This was a perfect competition. The diving conditions were lovely and the organization was flawless. I set two new personal bests therefore ending up winning overall and becoming the 2010 World Champion, in both the individual and the team competition. I would not have been able to do this without all of the wonderful support I received from my team and the other athletes. My final and winning dive was the best of the competition, I was completely relaxed and went into the deep blue with grace and comfort.”

The Mediterranean World Cup happens every year in Greece. Athletes compete in all three competitive depth disciplines, earning one point for each meter they descend, at the bottom they fetch a tag and must return to the surface and perform a timed protocol. The competition takes place over one week, during this time the athlete will have five diving attempts. The winner is the athlete with the highest overall score, calculated from their best score in each discipline.

The International Association for the Development of Freediving, AIDA, is the international sanctioning body for freediving, individual and team competitions, and freediving world record attempts. For more information about AIDA please visit

For more information about Jana visit

Thanks to the DIVEWIRE Staff for this article!!!

Kathy Dowsett

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Thursday, June 10, 2010

Lost Ships V: The November Witch

Dedicated to all the men who lives were lost as sailors from at sometimes the unprecitable storms of the Great Lakes.