Category Archives for "Scuba Diving"

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!

Snorkeling with Children – Fun for the whole Family!

Children appreciate family trips, especially when they get older. They can look back at all of the fun activities that they did with their parents. Snorkeling with children is one such activity that involves some skill and the right gear.

Children can learn this sport and enjoy it throughout their lives. After all, who doesn't love to poke their head underwater and take a gander at the fish? The following will present more information regarding enjoying this activity with your kids.

Three girls snorkeling in the ocean

How to Introduce Snorkeling to Children

Children can start this activity quite young. Trip Savvy goes so far as to say that kids can start at four or five years old.

The European Child Safety Organization provides more in-depth information on this matter. Kids need to know how to use the snorkeling gear before they go into the water.

They should also still be wearing flotation devices, even if they are proficient swimmers. There are basic hand signals that need to be mastered as well.

Kids also need to be taught to not reach out and grab what they see. Even if it is plant life, the motto should be, look, but don't touch.

This can be especially important because coral is sharp and can cut and scrape people up pretty badly. Parents need to ensure that the snorkeling space is safe - for example, they should take their children to areas with reefs so that the children are not swimming out in the open.

Also, parents need to tell their kids not to go into little coves. It’s easy for a kid to get curious and try to explore a cove or cave that has a lot of fish. These kinds of situations can easily lead to finding other sea life like eels which often can get children scared. This is not a pleasant surprise for a child.

Cute boy playing in the sea

What about equipment?

Children require pretty much the same snorkel gear that adults need. Yet, a couple of sizes smaller. There will be no joy for a kid to go snorkeling when the fins or mask don’t fit because they are too large.

The typical gear your child will require are mask, snorkel and fins. All of those can usually be gotten in sizes that match your children’s height and age.

It’s easy to understand that the fins need to be the right size for the kid’s feet. Otherwise, he or she will constantly slip out of them or they will be too tight if they are too small. Both will ruin the fun instantly.

When purchasing fins for children, adjustable fins are an option. This budget friendly buy can be adjusted as the child grows up.

A mask that’s not fitting right will leak and let water inside. This in turn will end any snorkeling adventure pretty quickly as it’s no fun to having to clear out he mask all the time.

Lastly, a snorkel that is not a dry-top snorkel will make it harder for the child. Especially in the beginning, it will be happening that your child will be getting too low into the water and the snorkel can submerge. If the snorkel is not dry then trying to take a breath will result in a lot of water coming in through the snorkel. The result being that your child has to come up and cough and ends up not liking the whole experience.

If you use a traditional setup with a mask and a snorkel then you also need to make sure that the mouth piece is small enough to fit into your child’s mouth. If it’s too large then it will hurt the kid’s mouth and make it impossible to breathe normally.

A newer and better way might be to get a snorkel mask covering the whole face for your child. They provide better visibility under water and make it a lot easier and comfortable to breathe. Many of them come in sizes specifically fitting children.

Make sure that you only purchase quality items. It can be a safety concern to have for example masks of low quality. The lens could be made from cheap material that breaks apart and could cut the face or the eyes of your child!

Ocean Reef Aria Full Face Snorkel Mask

Where to start?

People often do not know how to start their children with this sport. According to the European Child Safety Organization, the best place to begin is on land. The reasoning behind this is that children need time to practice before getting into the water. Even if an adult picks up the skill quickly, that does not mean that the child will learn as rapidly.

Two of the major concerns that ECSO suggests are that children need to learn how to breathe through the tube and keep the mask clear. The child might have to learn to do both at the same time if the tube clogs up at the same time as the mask blurs. They must be adept enough not to panic, but instead simply blow through the tube to clear the airway.

Dr. Orlena Kerek suggests in her blog that children can then get used to the breathing aspect in a pool. They will be able to learn the coordinate motions that go with swimming and using the gear.

Children in swimming pool learning snorkeling.

Once the child has become adept, the ultimate goal is the ocean. After all, they won't see fish in a swimming pool.

Snorkeling trips for the whole family

Many resorts will vie for visits from a family that loves to adventure and snorkel. The Travel Chanel suggests some destinations on their site - Most of their picks involve not leaving the resort property. This might be ideal as the family learns to adventure together.

National Geographic offers some advice as well ( Generations of families that visit Petit St. Vincent Private Island continue to pass snorkeling onto their children.


The entire family can enjoy snorkeling together. It will take a while to acclimate the children, but once this happens, the clan will benefit from the sea's sights.

There is a cornucopia of color and life below the surface of the water. It is waiting to be explored.

Father and son snorkeling

The ventures are fairly low risk, especially if the family chooses to stay in resorts that cater to snorkeler's. And with a little preparation, the family can take to the seas and inhale the open air.

Be sure to follow safety precautions because they are there for one's safety. It is best to ask the locals and hotel owners about any tips when staying on their beaches. They, after all, are trained to keep up to date with the latest weather and nautical conditions.

Prescription Dive and Snorkel Masks

One of the issues with scuba diving and snorkeling is that the masks can be a problem when you wear glasses and ruin the fun in or under the water. Depending on how strong your need for eye correction is you might not have to worry about it at all.

That is not true when you are far sighted and need reading glasses. You will need to be able to clearly read your gauges and that means that you somehow need to correct your reading vision while diving. For snorkeling that might not be true as you don’t have gauges to read that you’re safety depends on.

A dive mask will make any surrounding object around you appear larger and closer than they really are. If you’re just a little near sighted then this automatic correction of the scuba lenses might be enough so you can dive or snorkel without needing your glasses.

Dive Mask with corrective lenses

There are a few options available when you’re near sighted to be able to enjoy your dive or snorkeling.

Use your glasses

First, you can certainly wear your glasses and have some water drip into the mask. In many cases, it’ll end up being quite a lot of water as the skirt cannot create a tight seal with your skin. If your glasses have thin and flexible arms then it might work. Otherwise, the leaking will pretty much be unavoidable.

There are divers that will take an old pair of glasses and remove the arms of the glasses. Then you can place the glasses or your nose or mount them inside the mask. However, it will be a problem to keep the glasses in the right position and you can’t adjust them when you’re under water.

Another problem is that standard glasses tend to fog up and without being able to take the mask off to clean the glasses you’ll have a hard time to see anything.

Use contacts

Another approach is to use contact lenses. These can work ok but if you’re not careful you could lose them if you get water in your eyes while wearing them.

Some people have no problem wearing contacts in water while others cannot do that at all. If you can deal with it then it can be a great option for you.

One advantage you definitely have with contact is that they won’t fog up!

Glue Lenses into mask

One of the first possible solutions that was invented and at times is used until today is to glue corrective lenses onto the lenses of your mask. You will need to have special lenses created that have a flat surface on one side.

The side with the flat surface is what is glued against the flat lens of the mask. Most masks have flat glass so gluing the corrective lenses into the mask works pretty well.

The advantage of this method is that you can have the lenses match your prescription exactly including any other correction that is needed like astigmatism or even bifocals. You can glue them in the exact place you want and get excellent visibility that way.

One thing to be considered is that the lenses have to be in the right position in your mask. If they are not in the right spot then you can’t comfortably look out of your mask. Depending on the size of your head and the distance of your eyes, the lenses have to be glued in in the right location to make the mask work properly.

Dive Mask with corrective lenses

However, there are not only advantages to this method. One of the problems you can have is that sometimes these corrective lenses are very thick if you need a large correction of your eyesight. If you have glasses with more than five diopters and regular glass is used then the lenses will be very thick. As the lens needs to be flat on one side you end up with a large curve on the inside of your lens. Your visibility can get negatively impacted that way as you get a lot of distortion. Newer lenses for prescription glasses often use plastics which can be thinner and lighter and provide less of such an issue.

Another problem with glued in lenses is that they don’t have the same size and shape as the visor of your mask. This can make it quite difficult to effectively clean around the lenses. Eventually, you will have some dirt collect around the edge of the lens.

Using this approach is somewhat final for the mask you’re using. If you buy a new mask and it doesn’t fit you well then you usually will not be able to get your corrective lenses out again. You want to make sure that the mask will fit you well before you glue the lenses in. That way you make sure that it is the right mask for you. When you’re ready to have the lenses made and places you will have to find an optician that can handle that placement.

This is a reasonable approach to get a corrective dive or snorkel mask that will allow you to see clearly in the water!

Custom Prescription Dive or Snorkel Mask

If you buy a mask with split lenses, then it can be possible to replace the lenses in the mask with corrective lenses that are specific to your visibility needs.  This does sound easier than it is as you have to get the corrective lenses to match exactly the lenses you replace.

On top of that, the lenses in high quality masks are made from tempered glass. You do not want to replace them with standard glass or with plastic lenses as they can break easier and cause injury if you have an accident under water.

This option also only works if you get a mask with a frame. Frameless masks usually have the skirt bonded to the lens and as such you can’t just replace the lens without basically destroying (or at least risking destroying) the mask itself.

Some dive stores specialize to help with finding a good mask and getting the lenses replaced. If you find a specialist, then this is a great option. However, you can’t typically get this done online for a cheap price!

Off-the-shelf Prescription Mask

These masks are specifically designed to have lenses with corrections. You can usually find them online as well as in dive shops for reasonable prices.

This option works really well if you can find lenses that match your correction needs closely. You will typically be able to get the lens corrections within 0.5 diopters. This might not provide perfect visibility but is usually a tremendous improvement over diving or snorkeling without correction at all.

What these off-the-shelf masks cannot fix is if you require severe astigmatic correction. If you require a slight astigmatic correction or have just minor trouble with nearsightedness yet require a severe correction to see in distance then you can consider this type of masks and fix the major visibility issue.

You will not get a perfect match for correction with these types of masks. However, they are cheaper and pretty quickly available and as such they are a great alternative to the other methods and approaches outlined above.

Best Off-the-Shelf Prescription Dive and Snorkel Masks

There are a number of different corrective dive and snorkel masks you can find online. These are easy to get and affordable.

Promate Corrective Lens Scuba Mask

This specific mask is designed and manufactured with high-quality materials and is in any way equivalent to a good dive mask you buy without corrective lenses. The lenses are tempered glass and you can get a variety of different corrections.

Promate included even bifocal choices with this mask. You can get the lenses for far or near sightedness and you can mix and match as needed. The increments are by half a diopter and you can get corrective lenses up to +4.0 and -10.0 diopter!

This mask is with no doubt an overall great scuba masks. Even if you don’t need corrective lenses this mask is a good buy!

Scuba Choice Corrective Mask for Nearsightedness

This mask provides options for corrective lenses for nearsightedness. There are no options for farsightedness or bifocals.

It is a well-designed mask made from good quality material. The lenses are tempered glass and work well.

People have mentioned that the mask leaks. You will have to make sure that this mask fits you and adjust as necessary to prevent any leakage!

In our opinion this is a good mask but it’s not as well designed and built as the Promate mask mentioned above.

Promate Corrective Lens Snorkel Mask

This is another mask from Promate but it is more geared towards snorkeling. It is made from good quality material that are perfectly aligned with your requirements if you go snorkeling.

You can get corrective lenses for nearsightedness. The correction range is 0.0 to -10.0 diopter in 0.5 increments. The mask comes in a variety of colors and has a clear skirt to increase visibility to the edges.

For scuba diving we’d suggest to go with the above mentioned Promate scuba mask. This mask is great for snorkeling but you do only get corrective lenses for nearsightedness!

Ocean Reef Aria Full Face Snorkel mask with optional lens support

OceanReef offers an optional accessory that allows you to wear prescription lenses inside the Aria full face snorkel mask. You order the accessory and then have your prescription lenses fitted into the frames.

The advantage obviously is that you get perfectly matching lenses for your correction needs. Not only that, you’re able to use a full-face mask for snorkeling which in our opinion are superior as they provide better visibility and comfort.

If you are into snorkeling and need prescription glasses then this is pretty much the best choice there is. It’s not useful in any way for scuba diving though. You can even try (usually successful) to combine the accessory with other full face snorkel masks.

Final Thoughts

There are a number of options available for both snorkeling and scuba diving with regards to prescription lenses. Typically the best are to use off-the-shelf masks with optical corrections as close to your needs as possible.

For snorkeling you definitely want to have a closer look at the OceanReef Aria with the lens support accessory. You get perfectly matched lenses and combine them with a full face snorkel mask. It’s hard to imagine a better combination for snorkeling.

Scuba divers should have a closer look at the Promate scuba diving mask. It offers many lens options and by itself is a high quality mask.

Have a great time on your next dive or snorkel trip!

Can you punch a hole into ice if you dive underneath it?

If you’re not living in moderate and tropical climates then one thing you do face is that bodies of water can be frozen during winter. This opens an opportunity for many (or few) divers to go ice diving and explore a lake underneath the solid ice.

Can you or can you not break through?

One question if you’re interested in looking at this type of diving might be whether you could break through the ice from underneath in case you had to. What do you think? Can you or not?

Well, the short answer is: it somewhat depends but usually not. If you have a solid layer of ice on top of a lake then there’s pretty much no way that you could break through that layer from below.

Break through ice when diving

You simply don’t  have the leverage to do so. And no leverage then you also have no chance to break through the ice as it is quite sturdy as you might find out yourself if you ever try.

How thin does it have to be to break it?

If it’s a really (and yes, we mean really!) thin layer of ice then you potentially can get through. Otherwise, there’s pretty much no way as you can’t get enough power to break the ice.

Technically, you might have a chance to get through the ice with a pointy and sharp knife. Yet, even that often won’t work. The ice is way strong and sturdier than you would expect and anything thicker than a few millimeters will simply be too think and sturdy to get through.

All energy you can create to push against the ice is pretty much immediately lost once you hit the ice. And while you might think that the layer of ice is not very thick, it unfortunately is spread out pretty wide. And that absorbs pretty much any energy you can bring up from underneath.

A post shared by GoPro France (@goprofr) on

Breaking glass works the same

It’s similar to the windshield of your car. You might think that a strong push against he glass or even a stroke with a hammer would break it. Yet, that’s not the case. The energy from the stroke or push gets absorbed as you’re not able to concentrate the energy in a little pin-point. Using instead a nail that you hold against the glass and then stroke the nail even pretty lightly with a hammer will get the glass to crack.

Don’t ask how we know this…. Let’s just go with: we do…  img class=

It’s similar with ice. If you push against it you’re basically the blunt hammer. The energy you produce gets absorbed without any serious damage to the ice. If you could concentrate your energy to a tiny point then you possibly can break through even if it only would be a hole big enough to poke your snorkel through.

So, in short, ice diving can be amazing and fun but there are risks to it. Breaking through the ice sounds like a nice emergency plan yet don’t count on it. If you’re running out of air and have a frozen sheet of ice above your head you will be in trouble!

In the worst case, bring your own submarine:

How Deep can you Dive with your GoPro?

Diving is a complex sport that requires precision, skill, and confidence. It is extremely important to be prepared, in all ways, before embarking on an underwater dive journey. Having the proper gear is a part of that necessary preparation.

Divers, most times, desire to carry a camera on their dive. Although it is not of absolute importance, it is an item that helps divers make lasting memories. The GoPro camera is one camera option that can be used for diving. This camera has been around for quite some time, and is an excellent source for imaging.

How Deep can you Dive with your GoPro camera

History of GoPro 

The GoPro camera company was introduced in 2002 by a man named Nick Woodman. The first camera opened up in 2004 at 35mm, and has grown ever since. The GoPro Camera Company has boomed since their original opening in 2002, creating a large group of followers.

The purpose of creating this camera was to have a better way to film adventurous activities. Nick is a surfer, skier, and motorsport enthusiast and he wanted a better way to film his adventures.

The GoPro was created specifically for this reason and it also came with a wrist watch. His camera started from supplies of old wetsuits and plastic, and it eventually advanced and became highly technological. This company has grown tremendously and is quite well-known throughout the world, today.

GoPro is, now, an international company that is available in over 100 countries and they have sold over 26 million cameras. The passion of this camera company and the passion of their adventurous users bring thrill, inspiration, and celebration of life to reality.

Deepness of the GoPro Camera

Depending of which GoPro camera you purchase, the deepness and specifications will be different. GoPro, now, has four different models that are on the market. These models are the Hero Black 6, The Hero Black 5, the Hero Session 5, and the Fusion.

The design of each camera is different, but each camera has waterproof technology for going deep. The Hero Black 6, the Hero Black 5, and the Hero Session 5 all have waterproof design that lets the camera go up to 33 feet deep (10 meters). The Fusion model does not have the capacity to go that deep, but can reach up to 16 feet deep (5 meters).

Due to this, GoPro cameras have built-in technology for going underwater for long lengths of time. When you go diving, you will want to decide how deep you are going, what your goals are when you are diving, and why you are carrying a camera with you.

The waterproof technology of the GoPro camera helps divers of all capacities. If your camera bursts or breaks when you are diving, GoPro will exchange the camera at no additional cost, presenting you with a brand new one as well as backed up iCloud data.

Alternatives to GoPro

When you are planning to dive, you should first decide where you are going and what you want to see. This will determine how deep you go. When people begin to dive, they will usually not surpass 33 feet.

Yet, if you become more advanced or continue diving and want to take your skill further, it is possible to go beyond 33 feet deep. Due to this, it is important to decide what your diving goals are and then you can determine if it fits in the range of the GoPro. Through research, technology, and change, this camera remains as one of the top leading underwater cameras.

There are a few alternative cameras and each one goes a certain depth. Most camera companies have underwater options, such as Canon, Olympus, Sony, and Nikon.

There are many companies that have waterproof technology that let their cameras range up to 130 feet underwater and some even surpass 130 feet. Most of these cameras need housing to go this deep to remain waterproof.

A few popular models to consider are the Canon Powershot ELPH 300, the Nikon D810, the Panasonic LUMIX DMC-LX100, and the Sony Cyber-Shot DSC-RX100. Each model goes to a different depth, but all of these models have the capacity to go to 130 feet and some of them, such as the Nikon D810 and the Panasonic LUMIX DMC-LX100 have the capacity to go over 300 feet, ranging around 330 feet.

Evaluation of GoPro

The GoPro is a camera for the adventurist who wants to enjoy their life and capture it all at the same time. If you are going diving at a beginner level, the GoPro is the perfect camera. It is compact, well-designed, and helps capture life’s exciting moments without even trying.

The products of GoPro are designed to keep things contained while being reckless, and even if your camera breaks or bursts, GoPro will still replace your camera. This camera is recommended, unless you are out for something more professional and in need to go a lot deeper than the GoPro camera offers.


Diving is a complex sport and it’s adventurous thrill attracts people from all over the world. Whether you are going to have fun with your friends or to practice your diving skills, you will not be disappointed. Capturing your dives and playful moments underwater is an amazing attraction, and if any camera does it right, it would be GoPro. 

How to prevent Ear Pain from Diving

Diving is a sport that has become quite popular over the years. In fact, diving has risen in popularity in almost every country that has access to oceans or other bodies of water. When people decide to take part in the sport, having the proper technique is not only a necessity for the activity, but it is also a requirement for the health of all divers.

A health concern that has become common, while diving, is ear pain. Although most people do not have health issues concerning their ears, heading down into deep oceans can trigger this health concern. Understanding why diving triggers ear pain, how to prevent it, and how to fix these ailments can make all the difference in the world when taking part in this wondrous underwater sport.

What can you do to prevent ear pain from diving? Showing a detailed ear from the side.

Development of Ear Pain

When you jump in the ocean, you will notice the water has quite an impact on your body simply because your surrounding environment is changing. This happens when you go on an airplane, as well, because the pressure will be different than what your body is used to on a normal day-to-day basis. When you submerge your body in water, it lets you float, swim, and breeze through its substance. Yet, water also acts as pressure against the human body.

The biggest reason you with develop ear pain is because the pressure of the outside environment you are in is different than the pressure inside your middle ear. This is called “ear squeeze” because the air does not flow through your ears fast enough, even though the tunnel in your ear is opening up to allow it in.

If you do not let the pressure equalize, your eardrum will be in danger of popping. It can heal, but diving will have to stop during that time. If the pressure does not clear, you may come out of the water with something called barotrauma, which causes lingering pain after you dive.

Ear pain often occurs when there are respiratory issues, such as allergies or colds, that are not cleared up. Any bit of mucus will contribute to your ear pain because it will interrupt the natural equalization process.

Acting on the Pain

When you are in the water, you want to make sure that you allow air to flow through your ears when the tunnels of your ears open up. The pressure needs to stabilize in your ears when the pressure of your environment changes.

When you go down underwater, you want to make sure that you yawn, swallow, and allow air through your ears. There are a number of equalization techniques that you can apply to prevent any issues with pressure in your ear. You, also, want to let the pressure change at a rate that your ear can catch up with. Doing this can help with your ear pain.

You may want to float up if you notice pain in your ears because your ear may need to catch up. Sometimes, you will receive ear pain because the pressure changes at a quick rate and your ear does not have enough time to catch up.

It is suggested to descend in the water at a rate that your body can handle. You may, also, want to look up while you are descending. This can help with the transition.

How to Prevent Ear Pain

Ear pain usually comes if you have respiratory issues when you go diving. You want to make sure that you do not eat anything that will increase mucus production in your body, such as dairy products.

You also want to avoid diving if you have a cold. Although cold medicine can sometimes help, it is best to still wait until your cold clears up.

Additionally, you want to go through the equalization process throughout your descent in the water. You can start this before you even enter the water, by slowly blowing out of your nose.

It is suggested to be gentle with it and descend at a slow rate. The deeper you go down, the more you will need to equalize because the pressure will get stronger.

Making sure that your diving mask is clear of water at all times can also help with the prevention of ear pain. This can help keep your sinuses clear, so you do not produce large amounts of mucus while you are underwater.

This will make the process of equalizing successful. Most importantly, you want to be gentle with your ears while you are underwater. This is said to be the number one rule in diving. When the pressure equals out, you will feel the difference.


Diving is a sport that many love to take part in. When divers decide to head into the abyss of the ocean, sustaining proper health can make all the difference in the world. Understanding why ear pain develops, acting on the pain, and preventing it before heading into the ocean can help make any diver’s experience more enjoyable and successful, in the long run. 

The Essentials of a Good Dive Knife

When is a scuba diving knife a good one? 

There are essential components that may be necessary for most sports and activities. Knowing and preparing these essentials can make the world of differences. Diving is a sport that needs specific gear to create a successful and adventurous experience. 

Whether it feels necessary or not, one essential item is a diving knife. This item can help divers in the best and worst of times and it can provide enhanced confidence, safety, and adventure.

Diving is a complex sport that brings adventure, precision, and skill to an adventurous journey. Whether you are diving in a group, on your own, or if you are going on a deep and professional journey, having a knife can be very helpful. It is suggested to consider bringing this tool to your underwater endeavors if you are considering it. It can make all of the difference and it may make your journey one for the books.

What is a dive knife?

When divers go out into the sea, there are items that help with communication, safety, and for the journey to go smooth. A dive knife is one of those items.

Knives helps divers communicate with each other as they will make a noise when one diver taps on another diver’s tank. This is a simple way of communication while in deep waters.

Yet, these knives can help with any sort of entanglement as well. This basic tool can help divers cut through fish line or any other entanglement they come across within the ocean.

Sometimes, dive knives don't come across as used in the typical form of a knife, but are basic tools for specific help underwater. These tools can come from any material as well, but the most common types of knives are sharp, titanium or even stainless steel, and they usually have a serrated edge.

Details of the Dive Knife

Having a dive knife is very important for diving. Yet, beyond the basic needs of having a dive knife, there are other reasons why a diver should carry this item underwater.

To begin with, dive knives are used for emergencies and should not be used to mess with the underwater world, unless it is needed. These knives can help you get yourself or any friends that are diving with out of sticky situations, such as being stuck in a fishing line or fishing net.

There are other things that can get caught around divers as well, such as large amounts of kelp. If you need to use your knife to help sea animals get free as well, that may be a reason to carry one. Sometimes, the ocean current can be strong and attaching your knife to something underwater can help keep you in place.  As mentioned before, knives can also be used for tank knocking when you are with other divers.

When looking to purchase a knife, there are many kinds. To begin with, you may want to decide the style of knife you want. There is a leaf shaped blade, which is wide and has two convex edges. This knife type also has a sharp edge and is a strong blade.

There is the sheep foot blade, which has a straight cutting edge which is either smooth or serrated, and has a dull tip. There are two other types of knives as well.

There is the drop point, which has a long cutting edge, a strong tip, and curves down a convex blade. There is a clip point knife. This knife type looks like it was clipped at the end, is good for piercing at things, and it is usually used for curved cutting.

Purchasing a Knife

When you purchase a dive knife, you will want to decide what you need it for. From there, you can choose what kind of blade you need. The types of blades, as mentioned before, are the clip point, the sheep foot, the drop point, and the leaf shape. Each one can provide successful help for all divers.

When you are choosing the material your knife will be, it will mainly be based on preference. Stainless steel knives seem to have the best results for all divers, where ceramic and titanium knives, although they are successful, are different.

It is suggested to look at reviews and results, choose what you need, and then proceed forward. Ceramic and titanium knives are said to be more rugged than stainless steel. This does not have to be negative, but it can be simply based off of preference.

There are many things you may need to cut in the ocean, but the number one use for knives in the ocean is for maintaining safety by detangling yourself and others from fish lines, nets, and other things in the ocean. It can also be used for communication and to help you maintain stability when you are in the ocean.

Most divers who don't carry a knife seem to purchase one right after they get in a situation where they need one. Due to this, purchasing a knife and having it available, just for emergencies if anything, is important.


What can you do about Dive Computer Lockouts?

Do you stop your dive if your computer locks you out?

You’re on a diving trip and for whatever reason your dive computer goes into lockout mode and locks you out for a period. What can or should you do now?

What can you do about Dive Computer Lockouts

Why would your dive computer go into lockout mode?

First, there are several reasons your dive computer might go into lockout mode. There are many that are legitimate and a few that are strange. Without first evaluating what caused the lockout, you should probably not assume that the dive computer is wrong and ignore it.

All dive computers rely on their underlying algorithms. These are different between manufacturers and often also between different models of the same manufacturer. The result is a lot of confusion when you dive with a dive buddy that has a scuba computer and you’re ending up getting conflicting advice from your two (or more) devices.

Differences in algorithms

Suunto and Mares for example (and others) use rather conservative algorithms. They might require that you make deep stops or deco stops while an Oceanic or Sheerwater requires none of that. That doesn’t mean that one is right, and the other is wrong. But, it results in situations where diving gets confusing.

An example might be that you have a conservative device while your dive buddy has a more liberal variant. You dive together and your dive computer requires a decompression stop while your dive buddies doesn’t. If you ignore the deco stop your dive computer might go into lockout mode to prevent any potential injuries. And also to prevent any lawsuits against them in case something goes wrong…

Now, back to the problem at hand. If you proceed with the ascent and ignore the required deco stop the algorithm in your scuba computer requires, then it could (will) end up in lockout mode. A (bad) suggestion would be to tie the dive computer to a line and keep it at the required depth for the period of the required deco stop to fool it into thinking you performed the stop. The better suggestion is to follow your dive computer and perform the deco stop. It might annoy your dive buddy but better safe than sorry.

Suunto SME-ML Dive Computer

What can you do?

Back on land you might dig into the manual of your scuba diving computer and see what options you have. Many of the newer models allow to influence the algorithm through conservatism settings. If it’s as simple as adjusting those to reduce the chances of required deco stops then you can do that. You might also want to check your manual for other tips and tricks that relate to your specific dive computer.

But what do you do when your dive computer is in lockout mode? In that case your best choice is to wait out the time. You could dive with your backup dive computer but that would defeat the purpose of having a dive computer to help you stay safe. The same is true if you ignore the lockout and grab your dive tables to go back to calculate your dives yourself.

The story can be different if you were diving with a wrong setup. For example, if you would have forgotten to put the gas mixture to Nitrox and that way the computer calculated wrong based on a wrong assumption. Could you switch to a backup computer and dive again? Possibly you could but you don’t want to do that without doing the calculations upfront to know whether you can or cannot ignore the lockout. Alternatively, you might take the time to read through the manual of your scuba computer and make sure you know how to manipulate the algorithm and settings to make it calculate correctly…

Diver under water with a dive computer - what can you do when your dive computer goes into lockout mode?

Switch to a backup computer?

There are divers that have a backup computer they switch to in cases they don’t agree with the lockout of their main dive computer. While some claim it’s a perfectly fine strategy, we would advise against it.

If your dive computer goes into a lockout, then it does that for a reason. Without understanding that reason, it’s dangerous to simply ignore the lockout and switch to another dive computer. If you analyze why your dive computer has gone into a lockout and you prefer a more lenient algorithm, then it probably is time to buy a dive computer that gives you that leniency. Oceanic has a whole line of different models that will give you that. Other manufacturers do the same.

Otherwise, if you like the dive computer you have and you bought it in the first place to make your diving safer, then there should be no reason you’d want to ignore it when it tries to do just that! Except if it’s broken and provides you with bogus information. You also can dive within the no-decompression limits and avoid any issues that way.

Now to you. How do you handle a lockout for yourself? Do you ignore the advice of your scuba computer and use the backup or do you follow the lockout? Please leave a comment and share your thoughts.