Category Archives for "Scuba Diving"

Why are Snorkels so Short instead of Extra Long?

Have you ever wondered why the average snorkel is very short? It may seem as though an extra-long snorkel would be a better investment because it means you can reach greater depths. In reality, the short design of the snorkel is intentional. There are namely two reasons why the snorkel has such a short length. The first of those reasons involves a concept known as dead air space.

Reason 1: Dead Air Space

You are likely very familiar with the respiration process. During each breath, a person inhales air into the lungs. Once there, the oxygen is taken from the air and then supplied to the rest of the body via the bloodstream. Carbon dioxide is produced from the metabolized oxygen and is then exhaled.

Snorkel for adults

The conversion of oxygen to carbon dioxide occurs entirely within the lungs. However, there are other parts of the body where air is present. Inhalation also brings air into the wind-pipes, the sinus cavities, the nasal passages, and the mouth. The air that fills these locations is not utilized by the body and is thus not converted to carbon dioxide. Hence, these airs are known as “dead air spaces.”

The human body is strong enough to pull the air needed past these dead air spaces, though they could be considered obstacles. Another point to consider is that some carbon dioxide remains in the dead air space during exhalation. Once again, the body is adequately equipped to handle the small amounts of carbon dioxide that is pulled from the dead air space into the lungs during the next inhale.

When a person is using a snorkel that snorkel becomes yet another dead air space. The problem here is two-fold. First, it is, however, another obstacle for the body to pull air past. Second, it becomes another chamber that stores small amounts of carbon dioxide during respiration. The larger or longer the snorkel is, then it would increase the work needed to inhale, the amount of carbon dioxide stored in the dead air space, and the amount of carbon dioxide that would be inhaled. That is one of the main reasons why the snorkel must be designed carefully and often very short.

One possible technique that can be used to overcome this problem is the dual-tube arrangement. This requires one tube for inhaling air and a second tube for exhaling carbon dioxide. A valve is then used to control where the air can flow. However, this does not decrease the amount of dead air space that needs to be overcome during inhalation. It only prevents the reintroduction of carbon dioxide.

Reason 2: Pressure

Experts have determined that the maximum possible length for a snorkel without sacrificing safety is 16 inches. This was resolved not only considering dead air space, but also the second reason behind limiting the length of snorkels: air pressure. Let’s avoid the technical jargon and discuss the concept in its purest form.

As an object or person descends in water the amount of pressure on them is increased because of the weight of the body of water. This pressure acts on all aspects of the person, including their airspace. The extreme compression on the lungs prevents the muscles from being able to inflate them.

It’s estimated that the average human would lack the necessary strength to inflate their lungs and inhale at any depth greater than two feet. It just would not make any sense to design a longer snorkel even close to 2 feet because humans would not be able to use it.

What About The Diameter?

Snorkels for children
Portrait of happy cute boys wearing snorkeling mask ready to dive in sea

The previous points were focused on the length of the snorkel, but there is also reasoning behind the snorkel’s diameter. The average snorkel has a diameter of .75 inches, and it is intended to reduce resistance when inhaling. When combined, the length and diameter of the snorkel should be enough to supply the user with adequate airflow and minimal resistance without creating too much dead air space.

It is technically possible to increase the diameter of the snorkel, which would allow for creating a longer snorkel with the same amount of resistance. This would hurt the user’s ability to handle the snorkel under the water. They would also still encounter the problems described above.

One final point worth considering is that snorkels designed for children are meant to be shorter and have a smaller diameter. They are designed like this because children have smaller lungs and weaker muscles. A child should never use a snorkel that is intended for an adult.

Panic Attacks Underwater – How to Recognize and Prevent Them

The ocean is an amazing place with fantastic creatures and even more amazing sights. Luckily, we have the opportunity to go into the sea and see these things for ourselves by scuba diving.

With the proper equipment, we can go deep into the sea to discover things that we couldn’t imagine above ground. While diving is a great experience, you want to be sure to be extraordinarily careful. One of the most dangerous things that can happen is a panic attack while underwater.

Panic Attack while diving

A surprisingly large amount of deaths while diving involves panic attacks. Panic attacks cause 20% of scuba diving related deaths, and another 23% of the death attribute a panic attack as a direct cause of the death. Being underwater puts people in a vulnerable state.

We cannot naturally breathe underwater, so it’s easy to understand how someone can become frightened when something goes wrong. Struggling to breathe can cause anyone to panic, and that’s only one thing that can lead to panic. Here is everything you need to know about underwater panic attacks and how to recognize and prevent panic attacks from happening underwater.

What are the dangers of diving?

Diving is fun and beautiful, and it connects people to the mysteries of nature while allowing them to zone out and reflect, but it can also be quite dangerous. Here are some of the biggest things to worry about while diving:

  • Decompression sickness
    Depression sickness happens when you breathe in too much nitrogen. When you rise to the surface, this can cause serious problems, including nerve and tissue damage. Not only is this extremely painful, but it can also impede breathing. In some cases, it can even result in death.
  • Drowning
    An obvious danger of diving is drowning. If you aren’t adequately trained, go against your training or panic, it can result in drowning. Water will start to fill in your lungs and prevent you from getting the air that you need.
  • Arterial Air Embolism
    In some unusual situations, you may get air into your arteries that can cause the blood to stop flowing. This can happen if the diver holds their breath while ascending. This can be very dangerous, even fatal.
  • Nitrogen Narcosis
    After descending about 100 feet, divers can experience what is called nitrogen narcosis. The diver may experience brain fog and not be able to think properly. They may even experience the giggles and have a feeling similar to drunkenness. In this condition, the diver may not be able to make proper decisions. This lack of decision-making skills can lead to severe injury or even death. 

What are panic attacks?

Diving can be a dangerous activity. It’s only common sense to understand and accept this. When you know that you are going into a potentially dangerous situation, your body will release Adrenalin.

When your body releases a lot of Adrenalin, you will naturally respond with fear and anxiety. The proper amount of fear will cause us to go into a fight or flight mode, but too much anxiety may cause the body to shut down.

When the body shuts down, it can prevent us from doing the proper thing in an emergency. One of the most dangerous things about anxiety is that the higher the level of the panic attack, the less you will be able to help yourself. That’s why it’s essential to prevent or minimize a panic attack before it happens if possible.

Causes of a panic attack

There are many reasons that someone can reasonably have a panic attack underground. The deep sea is full of the unknown. This mystery in itself is enough to give someone a panic attack.

There are also heavy currents, dangerous marine animals, equipment failure, and physical problems that can cause someone to have a panic attack. Being underwater and experiencing difficulty breathing can make someone feel like the figurative walls are closing in on them and create a feeling of claustrophobia.

It’s also important never to force someone to go underwater if they are not ready; it will only cause a potentially life-altering problem. These are the reasons that can happen to people who don’t already have anxiety issues.

There are also some basic statistics to keep in mind. If someone has panicked while diving before, they are up to 2.7 times as likely to panic again. It shows a pattern, and you should be prepared to handle the pattern or not dive if you have had a panic attack before.

Women are up to twice as likely to panic as men. 24% of men reported having a panic attack while diving and 37% of women reported having a panic attack. Knowing the facts can take you to the next level.

What are early signs?

When you immediately recognize that you have a panic attack, you have a much better chance of doing something about it and preventing something hazardous from happening.

There are some signs of an anxiety attack. First, you may experience a general feeling of fear and inability to concentrate. Next, you may feel dizzy and short of breath. Other signs include irritability, nausea, muteness, and sweating. You’ll also notice that your heart is beating at a much faster pace than usual.

In its most severe form, a panic attack can cause the diver to act irrationally and make possibly fatal mistakes. The mask could flood, causing drowning and possibly death. 

It’s important to spot these signs in other divers, too. Remember that not all signs of a panic attack can be identified while underwater so be sure to pay close attention to the people you are diving with so that you can help in an emergency.

How can you reduce the risk?

There are several things that you can do before you even start a dive to prevent a panic attack from happening. Here are just a couple of prevention techniques:

  • Skill Training
    Get a refresher course if it has been over a year since your last dive. This will help you feel secure in your abilities. It will also remind you of safety procedures and what to do in the case of an emergency.

    If you feel the need to have extra assistance, go on a trip with an instructor or experienced divers so that you know someone is there to help you in the case of an emergency.

    Even if you are experienced, you also want to study the specific dive and practice your skills. Create a plan and follow it. You also want to be aware of your skills. It’s extremely dangerous to dive past your skill set.
  • Don’t dive drunk
    Never dive while intoxicated. Alcohol and drugs inhibit your ability to make the right decisions. It can also prevent you from being able to follow a plan and impair your motor skills.

    Finally, it can cause depressive thoughts which exasperate anxiety. Even caffeine can create anxiety, so be careful! You may think that a couple of cups of coffee before a dive is a good idea, but you could end up regretting it.
  • Acknowledge existing disorders
    If you already have an anxiety disorder, do not go diving until the disorder is entirely under control. Talk to a psychiatrist and get the proper medication.

    Remember that it can take a while to get your medication under control, so be sure to give it some time to ensure that you have the proper medication and proper dosage.

    Be sure to take note of any side effects and consider how they might affect a person while diving. Tell your doctor if you plan to go diving so that they can keep that in mind when they prescribe you medication. Also be sure to mention all other medical conditions and medications that you are taking.
  • Go with people
    While you may be tempted to go alone if you can’t find others to go with, you should seriously wait until you have a group of people to go with to help you in case something goes wrong. Learn how to communicate with your other divers effectively so that you can all be safe. This involves a lot of body language and merely being alert to those around you.

What should you do when you have a panic attack?

If you notice that you are having a panic attack while diving, you need to take immediate action. First, take a deep breath and analyze the situation. Next, concentrate on small breaths. If you are around other divers, get their attention for help. At the very least, you want to let them know that you will be heading back to shore for air.

Safely come back to the surface by having control over the regulator and keeping yourself as calm as possible.  It’s imperative not to ascend back to the surface rapidly. This can be very dangerous and lead to decompression illness.

This happens because of the dramatic change in pressure. Primarily, you will breathe in nitrogen. When you come back to the surface, you may create nitrogen bubbles. These bubbles, especially when left untreated, can be very painful and can even result in death in some cases.

Every diver is taught not to do this, but it can be hard to remember when having an anxiety attack. Luckily, 85% of people remember not to move up too quickly.

You cannot find an experience quite like diving. The more you dive, the more you will want to explore. After you get certified in diving up to 100 feet, you can learn more and get certified to dive even deeper.

When you dive deeper, you can see even more. Just remember that the deeper you dive, the more dangers you may face. Training will help you handle these dangers properly.

They will also help you learn how to manage the fear and anxiety that may come from these dangers. Be sure to take a deep breath if you become afraid and remember your training to reduce as many hazards as possible.

What you need to know about Oxygen Toxicity

One of the most dangerous problems in diving is oxygen toxicity. It’s having too much oxygen when you are underwater. It’s also called hyperoxia.

The air on land consists of around 21% O2 (oxygen). Without oxygen, we’re not able to survive. However, too much oxygen can also be a bad thing. It’s not the amount of O2 in the air that is of importance but the partial pressure of O2 (pO2). If that gets too high (or indeed too low), it’ll end up becoming toxic which can be fatal.

Oxygen Toxicity During DIving

What is pO2?

The partial pressure of O2 is measured in ATA (atmospheres). On the surface, you have 0.21 ATA (21% [0.21] times 1 ATA). Our bodies can sustain a pO2 of 0.16 ATA on the lower end. When often exposed our body can even adapt to lower pO2 levels.

On the upper level, we can tolerate pO2 levels of up to around 0.45 ATA for more extended periods. During shorter periods this level can be increased to more than 1.6 ATA. If you are exposed to high levels like that for a longer time (hours or days), then there will experience toxic effects that will first affect your lungs.

However, if you’re exposed to levels higher than 1.6 ATA, the toxic effects start at the brain. Even after just minutes of exposure! The danger is that one day you might not have any issues, but your body can react the next day by showing those toxic effects!

How to calculate?

When you dive, you will automatically be exposed to higher pO2 levels. Every 33 feet of depth increases 1 ATA of pressure. So, at 99 feet the pressure is 4.0 ATA. Diving with Air accordingly results in 4.0 * 0.21 which is 0.84. Quite a ways away from the limit of 1.6 we mentioned above.

The whole picture changes when we look at Nitrox. If we take a 40% O2 level in Nitrox, then you’re already at 0.4 ATA on the surface. At 99 feet with 4 ATA of pressure you get to 4.0 * 0.4 equaling 1.6 ATA! You’re passing the threshold where it can get dangerous for your health at that depth!

The table below shows at what depths you’re dealing with too high levels of pO2 during diving.

Depth (feet)

Pressure (ATA)

pO2 (ATA) for Air (21% O2)

pO2 (ATA) for Nitrox (40% O2)

























Diving with Air

Most recreational divers that only dive with air pretty much never have to worry about oxygen toxicity. There’s no way that you’d reach depths below 218 feet to face any problems. Why 218 feet? At 218 feet the pressure reaches 7.61 ATA. If you multiply with 0.21, then you end up at the ‘magic’ 1.6 ATA of pO2 where things become a problem.

Realistically, you won’t dive deeper than 130 feet and as such stay way above the depth where you would be exposed to oxygen toxicity. At 130 feet you end up at just a tad over 1.0 ATA. At 132 feet the pressure reaches 5 ATA which results in 1.05 pO2 (5.0 * 0.21). At that level, there should be nothing to worry about.

The air supply is also limited so there’s practically no chance to stay at even a 1.05 ATA pO2 that would be long enough to cause lung toxicity. You can’t bring enough air tanks with you to reach that limit!

Diving with Nitrox

Using Nitrox, the calculations change dramatically. An increasing number of recreational divers use Nitrox with up to 40% O2. In some cases, they might even use pure oxygen for decompression.

With these exposures to higher levels of O2, it can very quickly happen that you face oxygen toxicity. The table above shows that you reach a pO2 level of 1.6 ATA at only 99 feet! Compared to the 218 feet for Air, this is a depth that many recreational divers find themselves in regularly and for more extended periods of time.

The result is a real danger to your health! If you dive with Nitrox, then make sure to do your calculations upfront and to use a dive computer that alarms you when the pO2 limits are reached!

What damage can happen?

For the most part, oxygen toxicity will affect the human brain and the lungs. Long-term exposure will damage your lungs. The cells will die off, and your body won’t be able to absorb oxygen anymore which will lead to suffocation.

At pO2 levels between 0.45 ATA and 1.6 ATA, the most impacted organ is your lung. Above a concentration of 1.6 ATA, your brain will suffer.

What happens in your body?

Your cells in your body are built to be able to live within a specific range of pO2. Exposing them to higher levels for a long time kills them. Your body can withstand a certain amount of cells dying, but if too many of them die then eventually, you will die.

In most cases, we just are not exposed to high enough levels of pO2, or we’re not exposed long enough. The damage in those cases is reversible and as such usually doesn’t have a lasting impact.

As mentioned, the two organs most affected are the lungs and the brain. However, extended exposure to medium levels of pO2 can impact another part of your body – the eyes. The effect is that your eye can start to become near-sighted. This condition is also called hyperbaric induced myopia.

Lung Oxygen Toxicity

Going above a pO2 level of 1.6 ATA will impact the brain before the lungs. Prolonged exposure to elevated pO2 levels affect the lung, and you will feel mild irritation in the throat. The deeper you breathe, the worse that irritation will get!

The next stage is that you’ll experience a mild cough that increases continuously until it’s quite painful. At that time you usually cannot stop to cough anymore! If at that time the exposure continues you will feel tightness of the chest and difficulty in breathing. Shortness of breath also sets in. Continuing exposure will eventually cause death. The lungs cannot exchange CO2 for O2 anymore, and your body will not get oxygen, and you will suffocate.

Prevention of pulmonary (lung) oxygen toxicity is to limit the exposure to pO2 to the shortest time possible. Diving with air only and not diving below 130 feet should ensure that you’re not facing any issues.

When diving with Nitrox, it can help to add breaks where you switch to air instead of nitrox. That will allow your body to repair at least some of the cell damage in your lungs during the period in which you switch to breathing air. A possible scenario would be that for every 25 minutes of Nitrox you breathe at least 5 minutes of air. There’s no guarantee though that this will work to avoid oxygen toxicity of your lungs entirely. It can provide you with a more extended period though before its onset.

Oxygen Toxicity of the Brain (CNS)

Damage to the brain can happen much quicker than for the lungs. However, you will need to be exposed to higher pO2 levels. When diving with air that’s practically not possible to happen.

With Nitrox, the possibility exists. pO2 levels of 1.6 are reached at only 99 feet with a 40% oxygen level. Pure oxygen (100%) reaches this level at a depth of 20 feet! Be careful when you decompress on 100% oxygen!

Recreational divers using 40% Nitrox will usually not run a risk. The story is different for technical and commercial divers that go deeper and stay down longer on Nitrox!

The effects of CNS oxygen toxicity often come without warning. Some people experience a seizure with no other precursors like headaches, etc. While there is a good thing about seizures that arise from brain oxygen toxicity, there’s also a terrible outcome that is very real.

First, the good news (if we want to call it that). Because your body and brain are having so much oxygen on board, there’s most likely no permanent damage due to CNS oxygen toxicity when you experience such a seizure. The bad news is that because you have such a seizure, there’s a very, very high chance that you will drown. Or, if you ascend there’s a chance that you suffer pulmonary barotrauma which also can be fatal!

The symptoms of CNS oxygen toxicity range from convulsions (seizures) to tunnel vision, ringing in your ears, nausea, and dizziness. The seizures are the worst effect and can end in death.

You cannot prevent CNS oxygen toxicity through the use of any drugs. You can only avoid it by limiting your exposure to pO2.


To avoid any possible implications you want to stay below a pO2 level of 1.6 ATA. Diving with air will usually not let you reach that level but using Nitrox can put you at risk.

Develop a dive plan and stick to it. Make sure you stay below 1.6 ATA and even reaching that level should be for the shortest possible time. It’s better for your health while you’ll still be able to enjoy the wonders underwater!

Debriefing after a Dive – Waste of Time or an Important Habit?

You know how it goes. You're on the dive boat and prepare for your dive. Well, you should have prepared before but for argument's sake, let's say you do it on the boat.

Then you enjoy your time underwater and admire the sights to be seen. You get back on the boat and stow away your gear. Time to relax… Or, is it?

Is your dive over as you're out of the water and stowed your gear? Is it time now to socialize and chat away? Or does it end when you take your dive buddy/buddies and discuss what happened during the dive? What was good? What went wrong? What should be done differently?

Divers communicating underwater

Only by taking the time to analyze what happened during the dive will you be able to get down to any mistakes that were made and to avoid them in the future. Not reflecting on the dive results in you repeating the same mistakes again and again as you never consciously discussed them.

Debriefing after a dive allows you to do precisely that. You get input from other divers, and you'll be aware of mistakes that were made which you want to avoid. Similar, going over the dive allows you to discuss situations that arose which could have been handled better.

Now, most dives don't have any big mistakes as part of them. The ones that do usually don't end well for the participants. It is a known fact that if you replay situations, you encountered or that others encountered and mentally prepares for them and how to go through them you will less likely make wrong choices or even panic when those circumstances hit you underwater.

Group of divers ready to debrief

Having a debrief with a large group is usually beneficial for anyone involved if all contribute and discuss potential risks like sudden strong currents, etc. Just talking through such situations will allow you to become a better diver as you mentally prepare for them. In turn, you will be better prepared to react to those situations when you encounter them during a future dive.

Another important aspect is that you can compare air consumption. Consciously working on reducing your air consumption will allow you to extend your time underwater. And no, it's not about avoiding being the one to call a dive but to be able to enjoy longer periods under the sea!

These are the lessons you can go over to master different and difficult situations underwater. But there's another critical aspect of the debriefing. That part is where you can discuss communication issues underwater.

Remember when you were diving and you needed what felt like an eternity to get the attention of one of your dive buddies. Addressing this in a dive debrief raises the awareness of everyone involved that they have to pay attention to their partners!

It's not only to address if one or some of the divers in a group didn't pay attention to signals. It also has to cover when you and your buddy had a hard time understanding the messages of each other. Bringing that to the surface and coming up with a plan to improve the signals between you which in turn will ensure that you have a safer and more satisfying dive in the future. Because who would want to waste time underwater trying to understand what specific hand signals your buddy was giving you?

Being able to go over these experiences in detail can prove to be invaluable. They should be constructive and not a session to blame others for doing things wrong. Using them to improve your diving and techniques should be the goal for all involved.

How to debrief

The best way is to go through the whole dive. You want to start from the pre-dive planning, gear preparation and go over all the pre-dive checks you did. Bring up any inconsistencies or problems that happened.

Go through all of the steps and actions in chronological order. Small problems specifically at the beginning can lead to significant issues later on in the dive. Being able to identify them through the debrief is a tremendous learning opportunity and can teach anyone involved how to determine those issues in the beginning and then have a safer dive.

Don't only concentrate on the problems or near-problems that you all encountered. It's also important to look at the things that went well before, during and after the dive. Positive things can be improvements that you recognize in your buddies diving. For example, improved navigation skills of a diver in the group are something to point out in a debrief.

Pointing out improvements in your buddies and having a chance to discuss how they started to improve will also allow you to get tips and tricks on how to get better with your diving techniques. Lastly, it will motivate the other diver to continue to improve. Diving with better divers does eventually result in a safer and more enjoyable experience.

dive gear on boat ready for prep

Debriefs only with a big group in a training environment?

You’d think that having a debrief after a dive would only make sense after a dive with a large group or with a trainer. That’s very far from the truth.

Having a debrief after a recreational dive with your dive buddy can add a lot to your experience. Even a rec dive can be a moment to improve and learn something new. You might not get into that much detail with your buddy as you would in a larger group, but it can still be invaluable to have a debrief.

One topic you might have to discuss is whether your relative position to each other is how it makes the most sense. Sometimes divers end up right above each other. That pretty much makes it impossible for the diver at the bottom to see the body above him or her. Use the debriefing to bring up times during the dive where the positioning was not helpful.

The most commonly found debrief topic is usually the communication. Or, the lack of it. Or, how you misunderstood the signals of the other. It's good practice to bring those moments up and work through them so you can avoid them in the future. If you go diving, you want to experience the world underwater and not have to try to figure out what the hand signal of your buddy meant.

Who should lead the debrief?

It’s good practice that the most experienced diver or the instructor leads the debrief. If that’s you then make sure that you give everyone in the group a chance to bring up any issues (positive or negative) that they had during the dive!

Nobody in a dive group is perfect. Everyone will make little mistakes, have improvements or go through misunderstood signals. Bringing those up means that participants have to be good at bringing those issues up as well as willing to receive any criticism or suggestions. It’ll help all involved during the next dive!

Having debriefs from now on?

There's no law that there have to debrief after a dive. They can add a lot of value to the experience and allow all involved to gain trust and to improve their techniques rapidly.

Having a debrief routine as part of your dives with your buddy will make the next dives more enjoyable. You can discuss all those small issues you experienced, and that'll get you to become a better pair when diving. Addressing them in the open with your buddy or a whole group will significantly improve the trust between each other. A factor that should not be undervalued!

Initially, those debriefs might feel a little uncomfortable. You might have to criticize your buddy or be criticized. This is still a much better alternative than to endanger each other underwater or to waste precious dive time because you're trying to figure out what the other is trying to signal.

Make sure that you do your part in such a debriefing of staying positive and not let it end up being a blame session. A positive debrief that goes through the details will improve the diving experience and safety of everyone in the group!

The D-Mask – The last Mask ever needed for Diving or Snorkeling?

Slow down! Before you run out and try to get this mask that promises to revolutionize both diving and snorkeling you should slow down a bit.

Why do you ask?

Well, it's not yet available. It is a concept at this time, and as things go with ideas, it's not even sure that it'll ever be a product that you can buy.

The D-Mask For Scuba Diving

But boy, if the D-Mask was available today, I sure as hell would be running to get one. It's sleek, modern and looks way cool. If you're a Science Fiction fan, then this is all you've ever imagined since being a child. Well, besides being able to dive as deep as you want without needing air…. Different story…

So, what’s so cool about this particular mask. First, it’s a full face mask. For snorkeling, you’ll see those around everywhere. Just take the Tribord Easybreath or the Wildhorn Outfitters Seaview 180°. Both are some of the best snorkeling masks you can get.

And even for scuba diving, you can get full-face masks that are working very well. So, why all the excitement about this specific mask concept? In short, it's sleek, stylish, and different.

Snorkel or Tank?

It’s one single mask that you can either attach a snorkel to or a scuba tank. Interested now? Yes, you can use the same mask for both activities. That thought alone should count for something!

Let there be light!

Besides, there are some cool features integrated into the mask. First of all, the LED lights. They are built into the frame so you can get some lighting while you dive without having to use your hands.

D-Mask with integrated LED lights

Quite ingenious as it would be an overall pretty easy solution that could become part of some of today's masks. That would undoubtedly require that the lights are strong enough to produce some brightness that's sufficient for diving.

Talk away

Next, we have a bone-conduction radio. This would allow you to either listen to music or to communicate with your dive buddy. Something that currently is restricted to hand signals and boards to write on. Another entirely new improvement to how we dive and snorkel today.

Star Trek – Here we come!

Last but not least the mask also features a heads-up display. With that, some vital information like water temperature, depth, pressure and even weather conditions would be displayed right in the mask. Pushing the envelope farther, one could also envision the functionality currently in a dive computer to be provided that way. No more lifting your arm up or fumbling for the console to get the display into sight. It could all display on the lens itself.

How to secure it?

Similar to current full-face masks, it secures around the forehead, the sides of the head, jaws and the chin. Assuming that it does indeed create a tight seal, it'll provide a lot fewer pressure points on your face and will be more comfortable to wear and use.

The level of comfort also increases as you can breathe through your mouth or nose and you won't need a mouthpiece. This reduces or eliminated jaw fatigue and tremendously improves the comfort of diving or snorkeling.

D-Mask Full Face Snorkel and Dive Mask

The last positive that the D-Mask offers is also the same as you get with any full-face mask today. That is that you get a full 180-degree view as the lens is covering the whole front of your face. You can look up, down, left or right without the frame of the mask to restrict your view.

Is something missing?

This is a truly innovative design that in our opinion would make a good scuba and snorkeling mask. However, there are some features that we think might make this great design even better.

To make it a genuine contender for full-face snorkel masks it would be awesome if the mask had a mount for a video camera. Or, even better, build a camera right into the frame. That way it could be used for snorkeling and diving, and then there'd be no need to have a separate camera.

We do have a few doubts on how tight the mask can fit based on the images that ZJ-DDG has published. To make the mask safe for diving, it will have to be quite stiff, and as such, you'd need a pretty thick skirt all around the frame to make sure you can get a tight seal. This, in turn, could potentially create quite a lot of volume inside the mask which then makes it harder to use as a dive mask.

D-Mask Full Face Mask for Diving and Snorkeling

It also seems a little far-fetched when you look at the images that were published, and you see some of the guys with beards. It's tough to get a tight seal with any dive mask when you have a beard. It seems quite hard to imagine that this issue would have been resolved and will work without a problem when you're 50 feet underwater!

But, we’re nitpicking here. It’s overall a cool looking design that would seem to make a real nifty scuba and snorkel mask. We hope to see this design soon on the market and that we’re all able to try it for ourselves. Leave a comment below to share your thoughts on this design!

Images courtesy of!

Best Underwater Drones – Are they ready for prime time?

Drones are everywhere nowadays. News channels use them to make footage of accidents or sights of interest. The military uses them for who knows what. And then we randomly hear about near hits between drones and planes.

All of the drones we always hear about are flying drones. What about other kinds of drones? What about underwater drones?

No, not the remote-controlled mini-subs that are used to check down in thousands of feet underwater. More the ones that we could use to scout out a wreck dive we want to do. Or, provide us with video footage of fantastic sites under water? Guess what – they do exist, and they are amazing!

Best Underwater Drones

These underwater drones are equipped with cameras and lights, and you can send them down into lakes and oceans or any other kind of body of water. You can record and view all that they get into their sight without having to go into the water yourself.

Now, don’t get us wrong, we love diving and snorkeling but how amazing is it to think that you can get a perfect underwater view of any of the sights while you’re relaxing on a boat and not risking to violate any decompression safety settings? You take your drone and send it underwater while you watch everything as if you were down there yourself.

Only a few years ago underwater drones where super-expensive and no recreational diver would have been able to afford one. Nowadays, these drones are still expensive but no longer entirely out of reach. They are also easier to operate. The old min-subs that were used commercially required a lot of training to work them effectively and safely.

Before you run to the next store to get your underwater drone, take a moment and have a look at the best ones we found at this time. And be aware that they are not cheap. Drones that fly often look slick and smooth and have gotten pretty competitive over the years. The ones that have to survive the pressure underwater are unfortunately quite a bit more expensive and often don't look that stylish! There are more and more consumer underwater drones hitting the market, and that will eventually bring down the prices tremendously.

To make a choice simpler, we decided only to pick drones that are readily available. While you can read about many announced drones or drones where kickstarter or funding campaigns have started, we wanted to focus on the ones that you get and use.

What do you have to consider?

There are many different types of underwater drones. Compared to drones that there's a problem with transmitting the signals between the remote and the drone that's underwater. Wireless signals don't travel that well under water, and if you want a drone that can go to reasonable depths, you will need one that is connected by cable to the remote. That, in turn, does limit the depth you can reach as the length of the wire limits it.

What drones can you get?

Many different drones are available today that you can purchase. There are very cheap ones that you can use for videotaping in shallow waters down to about 10 feet. If you want a drone that reaches depths of 150 feet or more then you will have to have to open your wallet quite a bit farther.

PowerVision PowerRay Wizard Underwater Drone

The PowerVision PowerRay Wizard is one of the slickest underwater drones you can find today. It resembles the shape of a ray and has terrific technology packed into it.

The camera is integrated, and you can record in 4K UHD. It also allows you to shoot photos with a resolution of 12 MP giving you some impressive imagery when using the drone.

The drone connects with a 164ft tether to the base station. Commands transmit through that cable which does restrict the depth naturally to the maximum length of the cable. The batteries on the PowerRay last for up to 4 hours.

The remote transmitter that's used by the operator connects wirelessly to the base station. Besides changing direction, depth, and speed, you can also control the LED lighting in the drone to adapt and adjust visibility.

A neat feature is that the drone comes with Zeiss VR One Plus googles. You can view the images taken with this VR headset as soon as the photos or video are received. The Vision+ mobile app runs on iOS and Android and provides real-time viewing of videos and pictures taken by the drone. It's as close to being down there underwater yourself as it gets!

The feedback you can find is overall mixed. You'll need to have a solid understanding of drones to get the most out of this device. Assuming that you can drop it in the water and it magically does the video and photos and you'll have no problem working with the drone is not the case. You'll need to get used to how to operate the device.


The Robosea Biki is a different kind of drone. And that’s not only because it looks like a fish. While for example the PowerVision PowerRay is connected by a tether and cable, the Biki is a drone that you pre-program and then send on its way.

You can have it dive down to depths of up to 196 feet to take video or photos. Video can record in 4K quality. However, as the drone dives on a predetermined route without a real-time connection, you won't be able to see that imagery in real-time. It also means that you can't react to unforeseen circumstances as the route is preset and you can't adjust it on the fly.

At very shallow depths you can use the remote to drive the Biki, but if you want to use it down below a few feet, you will have to use a preprogrammed dive route. If you do not have the Biki dive at all, then you actually can control it with an app on Android or iOS to have it swim on the surface.

ThorRobotics Trenchrover110 ROV Underwater Drone

The ThorRobotics Trenchrover110 ROV Underwater Drone is an impressive underwater drone. It doesn't look as smooth and styled as some of the other drones we introduced, but it has some exciting capabilities in store.

You control the Trenchrover 110 through a base station that is connected to the drone by cable. The maximum dive depth is 30 meters which is the length of the cable.

This drone does have a built-in camera. Besides, you can place your GoPro or Sony HDR-AZ1 or compatible cameras into the drone to create videos and photos. By connecting your Android or iOS device, you can watch the images and video as they record.

Geneinno Poseidon I Underwater Drone

The Geneinno Poseidon I Underwater Drone is a fascinating device. It's neither shaped like a fish nor a ray but does in some ways outperform either one of the before mentioned drones.

The drone is connected to the base station by a tether and communication cable. The tether offers a length of 328 feet with a maximum diving depth of 394 feet for the drone itself. No question that this is plenty of depth to have fun with the device!

It features an HD camera with a 1080P resolution. You can capture full HD video or photos. To produce even better images, there’s a 120-degree wide angle lens on the camera, so you get a vast field of view for your pictures and video. You can watch the captured images in real-time on your mobile device.

You link your mobile device (phone or tablet) to the base station through WiFi, and you can control the Poseidon through your screen!

The Geneinno Poseidon I is built compact, so it's easy to travel with it. Being able to control the device in real-time makes it a blast to use and take video and photos during its dives.

ThorRobotics Underwater Drone Mini Mariana

Should the ThorRobotics Underwater Drone Mini Mariana be called an underwater drone? It seems more like a toy. 

It's not in the same class as the other drones we listed before. While these can dive down to substantial depths, the Mariana can only dive to 3 m. This feature doesn't sound impressive at all at first sight, but it still can make a lot of fun and great images!

It features a built-in HD camera. It's not 4K, but it does provide some reasonably good footage. You can have the camera record video or photos, and you can view them in real-time on your phone or tablet.

With the remote control, you can adjust the speed, direction, and depth and trigger the camera. The maximum range of the remote is 100 meters so you can get some decent range when operating the drone.

Are they ready for prime time?

Well some of them are. Others not so much. The price on the good ones is pretty high for something that's not much more than an exciting toy that can produce nice images and videos from underwater without you having to dive. 

We honestly think that it's more fun to scuba dive or snorkel yourself and experience the wonders underwater first hand. Photos and videos can be great fun but they don't replace first-hand experience.

Weighting to Dive – What you need to know about Scuba Weights!

Weights are an essential part of your scuba gear. Getting the weights right can be tricky as the correct amount is dependent on quite a few different factors.

To calculate the correct weighting for a diver, several factors have to be taken into consideration. These are for example thickness of the wetsuit, body mass and water salinity amongst others. Diving in the same spot with the same equipment reduces the calculation to a one-time event. However, that’s not realistic and in most cases, you’ll be switching locations and/or gear quite a bit.

There are quite a few ways how you can attach and distribute the weight when diving. Let’s have a look at the different types of weights you can get and where you can position them for a dive.

Weight Belts and Block Weights

Block Weights are the most common and simple types of weights for scuba diving. They are basically blocks of lead with a coating. The coating is most often vinyl or other types of plastic. The weights are coated to reduce the risk of damaging for example the boat deck if you drop a weight by accident.

Sea Pearls Vinyl Coated Lace Thru Weights

Click here to find the lowest price for block weights!

Your belt is threaded through the slots on the weight blocks. The belt itself is made from heavy duty nylon so it lasts and is able to sustain the weight of the lead. It usually has a stainless steel or plastic buckle to secure it.

The weight belt is worn above the hip bones. Fit it tight around your belly and distribute the weights evenly. You don’t want to have more weight on one side vs. the other as it will make it harder to stay buoyant.

Cressi Scuba Diving Freediving Spearfishing Nylon Weight Belt with Stainless Steel Buckle

Click here to find the lowest price for scuba weight belts!

If you want to use extra weight then you can add block weights to your tank strap. This can only add a little weight to your overall amount though.

You can buy all components of a weight belt and the weights itself. This allows you to create your own weight system the way you want it.

Soft Weights

It’s pretty obvious by the name that soft weights are not as rigid as block weights. They are pouches filled with lead pellets. The pouches are made from durable material and are completely closed to make sure that none of the pellets escapes.

Scuba Diving Shot Lead Soft Weight Bag in HD Cordura Pouch

Click here to find the lowest price for soft weights!

These pouches are then placed into a belt with pockets. The belt itself is usually made from nylon or other durable and sturdy materials.

Compared to belts with block weights, the soft weights and belts are usually more comfortable. The belt and weights can conform with your body shape which reduces the chance of discomfort or bruising.

Scuba Max Nylon Zippered Weight Belt

Click here to find the lowest price for dive belts with pockets!

An added benefit is that you can gradually lose weight in case of an emergency. If you have a dive belt with block weights you have to lose the whole belt. Soft weights allow to lose one or two at a time. The pockets on the belts are usually secured with Velcro or a zipper. In case of an emergency it’s easy to open to ditch weights.

Other Weights

Besides the weights that you attach through belts, there are other types of weighting systems you can use. Many modern BCD’s have integrated weights which usually means you can ditch your weight belt.

In addition, many of these BCD’s have the ability to attach trim weights on the back. These help to stabilize your position in the water.

Lead Weight Packages 40lbs for Scuba Diving BCs

Click here to find the lowest price for weights for BCD's!

The BCD’s with integrated weight systems have pouches that you can fill with weight. In most cases the amount of weight you can add to your BC will depend on the size of the BCD itself as well as the lift you can produce from the air cell. Make sure to check how to ditch the weight from the BCD in case of an emergency!

There are other weight systems you can leverage to perfect your buoyancy. Common types of such other weights are ankle weights and weights that attach to your tank or tank straps. Be aware that weight systems that attach to your back, whether on the BCD or the tank, might not be ditchable in emergencies.


Most divers will start out with a weight belt. The next logical step is to use a BCD with an integrated weight system. These are usually very convenient and comfortable to wear.

Before trying and adding different weights it’s better to work on improving your buoyancy through technique. It’ll help you more in the long run!

Liberal vs Conservative Dive Computer Algorithm

Using a Dive Computer with a Less Conservative Algorithm

One issue with dive computers that is always coming up is that they (pretty much) all use different algorithms. Specifically, the algorithms on one model tell you that you’re within your safety limits while the one of your dive buddy tells you to take a decompression stop or you’ll get bent. Which one is right? Or, to ask in a better way, is one right and one wrong?

Algorithms used in scuba computers are based on (theoretical) models. They are not adapted to the diver that uses the computer but are based on overall experimental data and theory on nitrogen absorption under pressure.

The result is that some algorithms are more conservative while others are more liberal or lenient. That does not make one safe and the other unsafe. There is no evidence that divers using less conservative algorithms experience the bends more often than their buddies using a more conservative model.

Conservative compared to Liberal Dive Computer Algorithm

Are all Dive Computer Algorithms safe?

You can overall trust that any of the dive computers available on the market today will keep you safe if you use them within their limits and follow their guidance. That does assume that you will be in somewhat decent physical shape and have no existing preconditions that you ignore which would prevent you from diving in the first place.

Divers that end up in trouble usually will do so for other reasons than the conservatism or leniency of their dive computer algorithm. The exception could be that a diver uses a computer that is geared for technical diving and that lets you adjust all different limits within the algorithm. Being inexperienced on top of using a highly aggressive algorithm could potentially lead to some problems while diving.

If you however use any standard dive computer off the shelf then you will end up safe if you adhere to the alarms and warnings. Some divers do think that they could or should outsmart their scuba computer by using two of them. That way they switch between the devices after each dive and ‘cheat’ the algorithm and history. If you diving computer does not know all your previous dives for the day then it certainly cannot calculate your limits correctly which in turn can get you in trouble!

Does it really matter?

It does and it doesn’t. You want to have your scuba computer in the first place to give you alerts and warnings when you get into conditions that could be harmful to your body. Usually, you want to follow the guidance to reduce the risk of getting the Bends.

Many scuba divers do not dive in the area they live in but instead go on diving trips. This is where the desire comes in to be able to dive as much as possible.

You just paid a ton of money to go on a scuba vacation and now you certainly want to make sure that you’ll be able to dive the maximum amount of time. A conservative dive algorithm can put a real damper on that…

Liberal Dive Computer Algorithm

Diving vacations usually end up with multiple dives a day spread out over several days. That does in turn result in quite a lot of stress for your body. To eventually make the decision on whether you are ok with a more conservative algorithm or not is somewhat a personal choice.

Common sense would say that if you are young and athletic then going the lenient route should pose no problem at all. Yet, being out of shape and a little on the older side might very well cause an overlap of where a lenient algorithm can enter dangerous territory.

Experience is in our opinion another important factor. And maybe experience is the wrong word here. It’s more confidence which comes through experience. When you are a new diver then you do want to squeeze every second out of a dive. Everything is new and the urge to be under water at all cost at times can lead to ‘stupid’ decisions. Like ignoring any warning signs or even alerts and staying underwater even when you shouldn’t. An experienced diver  is more likely to not ignore those alerts even if he or she knows that the algorithm is very conservative and leaves room to push the limits. This by no means should indicate that inexperienced divers would always take unnecessary risks but experience will be a factor when you are thinking of ignoring any alerts your dive computer might throw at you!

Another big advantage of having experience and confidence is that you are most likely more willing to call a dive. If you dive with a group and your dive computer is the one with the most conservative algorithm then you most likely will be the one that gets the warnings and alerts first. If you are a new diver you might be tempted to ignore your dive computer as you don’t want to be the diver that calls the dive.

Can you influence the algorithm?

Most, if not all scuba computers have the feature to set conservatism settings. These will change how conservative the algorithm calculates your warnings and alarms.

Lower end dive computers will allow very simple manipulations while technical dive computers have usually more complex adjustments available. In any case, what can often get divers into trouble is not understanding how the adjustments work.

It is good practice and it should be obvious that you read the manual and get yourself to understand clearly how the manipulations and adjustments work. It would be common sense not to try to read about it when you’re on the dive boat and getting ready for your dive. Take a few moments to read through the details and try them out before you go on a trip to understand how to set conservatism settings, etc. on your specific model.

Liberal vs Conservative Dive Computer Algorithm

Different types of algorithms

As already mentioned, there are a number of different algorithms around. They are typically grouped into two classifications.

The Pelagic Z+ based algorithms are the typical RGBM (Reduced Gradient Bubble Model) based variants. You’ll find those in Suunto, Cressi, Uwatec, Mares and Tusa devices to just name a few. These usually provide some limited adjustment possibilities and tend to be somewhat more conservative.

The other mainstream algorithm used is the Pelagic DSAT. It’s overall more adjustable and liberal. You’ll find this algorithm in many of the more technical scuba computers. The mainstream brands that use this as their underlying model are Oceanic, Aeris, Sherwood, Genesis and some other Tusa models.

The best of both worlds comes from Oceanic. They have figured out that when you’re diving in a group you will never have all divers use the same algorithm which can be frustrating for the ones that have to call the dive as well as the others where their device shows them that they have more time before reaching any limit. Oceanic dive computers provide two different algorithms and you can choose which one to use. This enables you to adjust your device to closely match the scuba computers of other divers in your group.

DSAT based algorithms are typically considered more aggressive or liberal compared to RGBM based algorithms. They typically will be found on devices that are somewhat more expensive and technical. In short, they don’t target the entry level market.

Which Scuba Computers use the most conservative algorithms?

Most, if not all dive computer manufacturers use their own algorithm. Some are more and others less conservative. When you look at the more technical dive computers you will usually find more adjustment capabilities as the assumption would be that you have a good understanding of what the impact of those adjustments is.


It’s pretty much common knowledge that Suunto uses a very conservative algorithm. You can somewhat manipulate it through the conservatism settings but it overall tends to be the most conservative algorithm you can find.

Again, that does not mean it is worse than others nor does it mean that it will keep you safer. You’ll be usually safe if you don’t ignore any warnings or alerts from your dive computer.

Yet, it undoubtedly can be frustrating when you are diving with your buddies and you end up being the one whose diving computer starts to ping first as it’s warning you to start to go up again. All others still show that there’s plenty of time yet your device tells you to prepare for ascending.

Cressi’s RGBM algorithm

Cressi overall also uses a rather conservative algorithm. It’s probably not as conservative as the Suunto but comes pretty close. In some situations you might even find it to be more conservative than Suunto’s algorithm is.


Mares, similar to Cressi and Suunto uses a RGBM algorithm. It’s also pretty conservative and depending on the model you have more or less adjustment capabilities.


Oceanic, as already mentioned above, typically has two different algorithms in their computers. You will get a RGBM and DSAT based algorithm and you can switch between the two as needed. This is a great feature when you dive with a group as you can get closer to what other dive computers have.


Atomic uses a recreational RGBM algorithm that is based on the Dr. Bruce Wienke model. It’s not an overly conservative algorithm but it is also not a very liberal one. Realistically it is somewhere in the middle of the pack.


Shearwater dive computers are mostly technical in nature. Both the Petrel and Perdix models offer a ton of adjustment capabilities and pretty much lets you influence the underlying algorithm to the n-th degree.

The Perdix uses a Bühlmann ZHL-16C algorithm with Gradient Factors. This allows for the most adjustments you can find today with any of the dive computers available. Changing the gradient factors allows you to change the model to be as aggressive or conservative as you want it to be.

Compared to other scuba computers you can not just only set the conservatism settings in a few preset ways but have pretty much full flexibility to adjust different factors for the device. It’s close to coming up with your own algorithm. Yet, be aware that you should really understand what you’re doing when you start to manipulate the algorithm that way!

Conservative Dive Computer Algorithm

Which is best?

There honestly is no perfect answer. It depends on what you’re comfortable with. More conservatism provides (theoretically) more safety. Yet, do not forget that safety here is based on theoretical models that have over time been justified through empirical studies.

No dive computer will give you a guarantee that you won’t experience DCS (Decompression Sickness). A lot of considerations have to go into your personal calibrations and adjustments.

The one thing you definitely should think about is not to have two different dive computers when you’re diving with the same partner all the time. In that case it will be the least frustrating to have the same device and the same settings. Otherwise, one of you will always be the one to having to come up first!

For recreational divers the best overall seems to be Oceanic’s scuba diving computers. The ability to switch between two different algorithms makes them the most versatile. More experienced or technical divers might consider Shearwater devices as they will let you adjust to your hearts contempt.

Using any dive computer with Gradient Factor adjustments, like the Shearwater models, does provide you with the ability to set the conservatism to any level you like. It would be wise though to have a really good understanding how and why you do those adjustments!

Best Places To Snorkel In The Caribbean

Are you thinking about taking your next vacation in the sunny and gorgeous Caribbean?  Why not combine great food, a fun atmosphere and perfect beaches with the ideal snorkeling experience?   Get up close to the Caribbean's local marine life and fully explore the fascinating underwater world.

Adventurous travelers are aware that after you are tired of exploring historical sites, and can't stand the idea of visiting another museum, and you've walked through every single open-air market there is, that there is just one thing left for you to do - go underwater. 

Best Places To Snorkel In The Caribbean

When it comes to exploring underwater, scuba divers do have the greatest amount of freedom.  However, is exciting enough even for jaded travelers, and easy enough for kids t do.  So whether you would just like to get close to a friendly shark or are exploring an underwater ecosystem with a marine biologist, snorkeling gives you the chance to become fully immersed with nature.

The following are some of the best kid-friendly snorkeling areas in the Caribbean that truly amazing.

Bloody Bay Marine Park, Little Cayman

The mile long and one mile wide Little Cayman Island is situated in clear stunning waters which makes for some the Caribbean's finest diving and snorkeling.  Surrounded by dive sites, reefs, and wrecks, Little Cayman is family-friend and a great place to visit for people who are serious about marine life watching. 

Practically untouched, the reefs of the island are full of underwater life.  It has marine park status to protect the marine life there.  Blood Bay might sound scary, however, it is actually a gorgeous underwater paradise that features Three Fathom Wall, impressive coral cliffs, and creatures such as the odd Lionfish, huge barrel sponges, rope sponges, and the hawksbill turtle.  Stingray City, which is in the Caymans and busier, if a family favorite for visiting these amazing creatures.

Glover’s Reef Marine Reserve, Belize

Glover's Reef is situated approximately 30 miles from the coast of Belize and belongs to the Meso-American Barrier Reef.  A marine reserve and World Heritage site, it is home to a complete atoll along with a lagoon that is 80-square-miles where plenty of turtles, sharks, and rays can be seen.  

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From March through June you can see the whale sharks.  There is a resort on Glover's Atoll to provide the quintessential Robinson Crusoe Experience.  Book a thatched cabin situated over the water or camp, to provide you with the fastest route to idea diving or snorkeling, with abundant coconut trees and white sandy pristine beaches at your doorstep.  The perfect paradise awaits you!   

Underwater Marine Park, Curaçao

A spectacular and rich marine life can be found in Curacao.  Head over to the Curacao Underwater Marine Park running along the southern coastline of Curacao for 12 miles.  This family-friendly park features one of the top snorkeling spots in the Caribbean. 

You will have so many choices of things to see from an incredible array of fish everyplace you look, to coral gardens and sunken ships.  Some of the most popular snorkeling sites in flat water on the calmer western side of this island include the beaches of Knip, Playa Abou, Grote Knip, Jeremi, Lagun, Cas Abou, Porto Marie, and Daibooi.

Bird Island, Antigua

Antigua is home to 360 beaches, which is almost one beach for each day in an entire year.  The waters here are very impressive.  Calm, clear waters are loaded with colorful tropical fish, brain and elk coral, and anemones. 

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For everything ranging from small fish, to whale sharks and tune, take a trip over to Cades Reef or Bird Island where the Caribbean and Atlantic meet.  However, be aware of the currents - in certain weather they may be treacherous, so be sure to keep a close watch on your kids.

Canouan, The Grenadines

Most of the family-friendly Grenadines islands offer the ideal conditions for snorkeling, whether you are going to Petit St. Vincent and Palm Island, the  Canouan and its mile-long reef that is full of vibrant fish and brain coral. 

The kid-friendly Tobago Cays is another option where you can see eagle rays, nurse sharks, turtles, whips, fans, and soft corals in the beautiful warm, calm waters.  Check out Horseshoe Reef, which protects four uninhabited islands out of five that belong to Tobago Cays Marine Park.  This protected coral-reef system is full of color and only 12-feet deep.  Try the Baradel beach for turtles.

Buck Island, US Virgin Islands

This island has a great reputation for being one of the Caribbean's best family-friendly snorkeling areas.  With more than 250 species of crustaceans, corals, sponges, and fish, the 840-acre reef system and island are located two miles away from the north shore of St. Croix and is a must see!  This is a US National Park that is protected but is still open to snorkelers and divers.

Snorkel in between the gorgeous elkhorn coral barrier reefs underneath the brilliant blue waters of Buck Island as you are following colorful parrot fish across an underwater trail that winds through the sunken national treasure.  In the park, there are three different sea turtle species that nest there, with abundant brain coral, and threatened least terns and endangered brown pelicans calling the island home as well.  For beginning snorkelers, the gentle, shallow waters are perfect. 

Ambergris Caye, Belize

Outside of Australia, the largest barrier reef of 185 miles is located in Belize.  There are numerous opportunities here to get up close and see rays, eels, and all types of bright colored fish.  Dotting the Caribbean coastline are hundreds of atolls and cayes that are full of colorful coral that is sunk underneath the turquoise waters. 

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Some of the finest options for snorkelers and divers can be found just off Ambergris Caye, which includes Hol Chan Marine Reserve along with shark ray alley which is full of nurse sharks that will gladly allow you to fulfill your fantasy of swimming with sharks.   

Cayo Diablo National Park, Fajardo, Puerto Rico

Cayo Diablo is set off the Caribbean and Atlantic and is a 20-minute boat ride away from Fajardo, Puerto Rico.  It is renowned for its green and hawksbill turtles that live in the area's shallow waters. 

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These waters are also the home of staghorn and elkhorn corals, in addition to numerous colorful tropical fish.  Visit in style at the Waldorf Astoria Resort called El Conquistador Resort.  It is located perfectly for exploring both sea and land and is situated between the marine national park, Seven Seas Beach, and El Yunque National Forest.

Champagne Reef, Dominica

Caribbean Travel & Life Magazine rated this as the No. 1 snorkeling site out of 25 snorkeling sites in the Caribbean. It is one of the finest natural attractions in Dominica.  Subterranean geothermal push tiny bubbles up through the ground to give the reef its fancy name.  

Swim through these bubbles and get up close to sea lobsters, parrotfish, frogfish, and seahorses, along with a paradise o gorgeous Hawksbill turtles and beautiful corals.

What is Trimix?

Trimix, simply put, is a blend of helium, oxygen, and nitrogen that allows divers to reach depths previously thought impossible. The exact percentage of the three will depend on the depth of the dive. The deeper the dive plan, for instance, the amount of oxygen and nitrogen will be lowered and the helium increased to prevent nitrogen narcosis and oxygen toxicity. The math behind the exact percentages is quite precise and complex.

What is Trimix

Oxygen and nitrogen are pretty standard when it comes to breathing gas, so you may be asking yourself why helium was chosen as the third element. For one, helium has a lower density, which is easier to breathe at extreme depths. With smaller bubbles than nitrogen, diffusion of helium in the tissues and blood is much faster and easier than other gases, lowering the risk for getting the Bends. Helium is also non-reactive with other chemicals and much less narcotic than nitrogen. Indeed, many divers express that they feel better after finished a dive with mixtures containing helium rather than solely nitrogen and oxygen, though the claims haven’t been empirically tested.

Unlike some other breathing gas mixes, Trimix is reserved largely for professional or technical divers. Recreational divers generally wouldn’t reach the depths necessary for these special measures. We’ll talk a bit later on why this mixture is reserved for specialized use.

What’s the history of Trimix?

Trimix is one of the advances in the world of scuba diving that we can attribute to the military. At the end of World War II, the US military and British navy began to experiment with diving technology, to see if they could reach new depths. One of the experiments that they conducted was around the use of Helium in saturation diving to reach sunken military equipment.

For a few decades, the results of these studies didn’t branch out of military circles, but by the 70s and 80s, helium mixtures were being used by technical divers for cave diving. A decade later, practices were being standardized in terms of training, making trimix more widely accessible than it was just thirty years before.

Today, trimix is used for pretty much any dive that exceeds 150 ft.

Are there drawbacks?

Since helium seems to be a cure-all for issues of toxicity and narcosis, it’s interesting that not all tanks are filled with the stuff. But there are a few good reasons why it’s not more commonly used.

For one thing, helium comes with additional expense. This is largely due to the fact that it’s not that easy to get and it requires special training. Decompression with trimix is slightly more complicated than traditional mixtures, so divers must be trained on how to avoid decompression sickness.

Another disadvantage to helium is that it lowers body temperature and puts divers at higher risk for a condition called High Pressure Nervous System or HPNS. Once called helium tremors, this condition can sometimes occur for dives exceeding 600 fsw and manifests in fatigue, nausea, shaking, and cognitive disruptions. While very uncommon, researchers still worry about this risk of breathing helium.

Even with these drawbacks, mixes that utilize helium are overall very safe and even preferable to more standard breathing gases.

How can you learn more?

Trimix isn’t something that you would simply put in your tank and dive as normal. There are a lot of factors that go into finding the right mixture, and you should be prepared to take a few classes to get certified in using trimix. Check with your local dive community to learn more about prerequisites and opportunities to join a class.

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For PADI certification in Trimix, for instance, you need to have a PADI Tec 65 Diver certification as well as 100 logged dives. You must also be over 18 years old and have medical clearance.

In a class like this, you’ll learn key skills like planning trimix mixtures for different depths, handling multiple decompression cylinders, use of decompression software and multi-gas computers. You’ll also, of course, learn how to deal with emergency situations, which is extremely important the deeper you plan to dive. An initial class on trimix with PADI would allow you dive to depths of 210 feet (or 65 meters) or less, meaning that there is still more to learn on the topic of trimix before you can think about diving even deeper.

Take your diving further.

For those who are contemplating becoming certified in trimix, it’s a good idea to do extensive research on the ins and outs of how to use the breathing gas. With a solid theoretical base, you’ll be sure to enjoy your certification classes and be safer in the real-world environment!

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