by: João Neves & Christian Thomas

I was amazed to recently find out that among some diving communities the classic notion that Helium is a “cold” gas to breathe still lingers…” So I thought that this subject should be revisited.

So is Helium “cold”? Well, it depends on how it is used. I hope that by reading this small text (small for such a big and complex subject) the reader will be able to make an educated decision.

Let’s start by presenting some definitions that will help us along the way:

Thermal Regulation


Birds and mammals are homoiothermic, this means they have a physiological ability to maintain a constant body core temperature that is typical for each species. In man, typical core temperature is around 38ºC. To achieve constant core temperature our body uses thermoregulation mechanisms triggered by nerve temperature sensors. Skin sensors will trig fast and dramatic physiological response and for temperatures above 45ºC and bellow 10ºC, it will be perceived as pain. Other sensors are located deep, in the hypothalamus region of the brain and on the spinal cord. It triggers response only when core temperature has dropped significantly.

When core temperature tends to rise (hyperthermia), blood vessels in the skin dilate to increase heat exchange surface with the exterior, acting much like a car radiator. Sweat will occur and water evaporation will further cool skin surface, helping to drain excessive heat. There will be an increase in breathing rate to further eliminate heat through lungs.

When core temperature tends to drop (hypothermia), vasoconstriction occurs to reduce heat loss through the skin. Vasoconstriction will shift fluids to central regions of the body. This will have the adverse effect of increasing diuresis and will lead to dehydration. The body concentrates on heating the central organs and limits heat exchange with the outside. Metabolic activity and breathing rate will increase to generate more heat to compensate for thermal losses. It takes 15 to 20 minutes for thermogenesis to reach its peak.  After this, activity will start declining as energy stocks become depleted and in two hours energy production will be half.

Two types of exposure to cold can be defined:

Sudden violent exposure to cold, will involve neural “cold” sensors in the skin and immediate response of thermoregulator mechanisms like hyperventilation, extreme shivering, and reflex vasoconstriction. In very low temperatures it can be followed by heart syncope and respiratory failure. It is a strong neurological reaction that is triggered even if core temperature remains within normal values.

Slow long cooling of the body, on the other hand, is the type of exposure divers experience in deep diving. Nerve reactions are reduced and go sometimes unnoticed. Periphery vasoconstriction will develop from the beginning, in an attempt to reduce thermal exchanges through the skin and keep core temperature. Other physiological reactions and extra energy production are slow to respond.

When thermogenesis can no longer cope with thermal losses core temperature will start to drop. The diver is unaware of the slow onset of dangerous hypothermia. When it reaches 36ºC, the diver may no longer be able to think and act properly to safely conduct the dive. Also, the radical physiological changes will prevent a “normal” elimination of inert gases from tissues, leading to increased DCS probability.

Heat Loss

As we have seen above, keeping body temperature is vital in deep trimix diving. As an Extended Range Diver, you should know by now that anything that interferes with normal blood circulation may lead to a DCS increased probability. Hypothermia leads to blood vessel constriction that will limit the amount of blood flowing through peripherical tissues and thus the capability of draining inert gas. Controlling exposure should, therefore, be a top priority for the trimix diver as heat loss increases dramatically with depth and a lot longer hang times. In this section you will learn that heat loss occurs in several ways:

Respiratory Heat loss (through lungs)

–    Heating inspired gas

–    Humidifying inspired gas (Latent heat)

Body heat loss (through skin)

–    Radiation

–    Conduction

–    Convection

Body heat loss can be copped with by carefully selecting correct procedures, equipment, and thermal protection. However respiratory heat loss cannot be easily avoided or controlled. This becomes a major problem in long deep dives and should be addressed and taken into account.

Respiratory Heat Loss: Lungs

Gases undergo dramatic depressurization when flowing through SCUBA. At a depth of 80 m at the beginning of your bottom time, your bottom mix goes from 200 bar to around 19 bar, and from 19 to 9 bar with each breath. The sudden decrease in pressure cools the gas to a very low temperature sometimes bellow 0ºC. The final temperature of the inspired gas depends on water temperature and volume/mass of gas that is decompressed. The deeper you go the colder the water and more volume of gas needs to be decompressed, the cooler the inspired gas will be. We cannot “detect” this low inspired temperature, as we do not possess “thermal sensors” in the respiratory tract (trachea and lungs). Body reaction to limit this thermal loss will not be activated until late in a hypothermic state.

The lungs at alveoli level are perfect heat exchangers due to their very large exchange surface. They heat and humidify almost instantly the inspired gases, bringing them to a core temperature of 38ºC, regardless of the inspired temperature. On the other hand, bronchioli and trachea are bad heat exchangers. Also, they represent the respiratory residual volume. The residual gas volume is only partially re-heated. When resting, the tidal volume is about 0.5 liter. In moderate effort, tidal volume may be around 1.5 liters. Residual volume is about 0.15 liter. The tidal volume is therefore not all brought to core temperature. A reasonable assumption could be considered, that only about 80% of the tidal volume is heated up to 38ºC.  At 80 m the volume to be decompressed is 9 times bigger than at the surface. This means that at depth, you would lose heat via lungs 9 times faster then you would on a freezing cold day at the surface.  We will be using these figures later on for some interesting calculations as all of this warm gas is exhaled with each breath and with it, precious calories go to waste.

Deep commercial divers, be it saturation or bounce diving, are well aware of the danger of this thermal loss so they are supplied with pre-heated gas when inside the saturation facility or via the supply umbilical when outside. In case of interruption of gas supply, ruptured umbilical or similar incident, they need a bailout capability. Sudden exposure to dense, very cold inspired gas may result in a critical nervous reaction with choke due to contraction of the glottis. Open circuit bailout is therefore not advised. In depths of 150 m or more, they need moist and warm CCR bailout gas.


Portugal Rui-Guerra 2

Heat Loss by evaporation – Latent Heat

Most of the gas cooling takes place at the regulator first stage high-pressure valve seat. As we breathe, this is repeated; inspiration after inspiration creating a “freezer effect” around the valve seat area that will get cooler and cooler. This area will be drawing heat from the regulator body that in turn receives heat from the surrounding water. Eventually, the temperature of the valve seat area will reach a steady state, but it will stay well below freezing. Any moisture in the gas will turn into ice and build up at this place, sticking the valve assembly in open mode. Once this happens there is no stopping the flow of gas. Intermediate pressure will increase and open the second stage valve into free flow. You better be quick closing that cylinder valve; you only have a few seconds until the pressure gauge pointer slams into the zero limiting pin! In order to prevent this well know phenomena from occurring the breathing gas must be fairly dry. This is why compressors are equipped with filtering systems and condensate drains for water and there are standards for water content in scuba breathing gases. Remember that the deeper you go the cooler the gas gets, and the more likely a regulator is to freeze. So, watch out those filter elements on your compressor when filling trimix!

Moisturized gas simply cannot be used deep with scuba, so we must breathe very dry gas. As we stated above, gases are also humidified at the lungs. This moisturizing is achieved by evaporation of water at the alveoli internal walls surface. Evaporation implies heat transfer, as energy is needed to turn liquid water into water vapor, and thus further temperature drop. This transferred energy is called “latent heat”. Latent Heat is independent of depth and is approximately 10 W for an RMV of 20 liters/minute. Humidifying the inspired gas does not only drain energy from our lungs it also is a major contribution to dehydration – also a major player in the onset of DCS. More about this later.

Tip: breathing a two-meter long hose regulator will dramatically reduce respiratory thermal loss. In fact, it has been shown that inspired gas temperature will be several degrees centigrade higher than in a regular length hose, depending on water temperature. The time gas remains in the long hose before it is inhaled is enough for gas to draw some heat from surrounding water. It would be a good idea for independent doubles divers to consider using 2 m long hoses in each of their bottom regulators!

Total Respiratory Thermal Energy Loss

How much does respiratory loss contribute to the total thermal loss during a deep dive? Due to its well-known high heat conductivity, does helium in the breathing mix aggravates this loss, as is so often seen stated? Let’s do some calculations and quantify it:

The energy used to heat the gas is proportional to gas mass and depends on gas properties. The deeper the diver goes the higher the mass of gas to be heated.

The formula is:

Thermal loss = Cp x 0.8 ( 38 – IT ) x Q x P / 60 + LV


IT – Inspired gas Temperature
Q – Inspired gas Volume (liters/minute)
P – Absolute Pressure
Cp – gas heat Capacity
LV – Latent Heat

A gas with a high Cp will require more energy to reach a given temperature and conversely will give away more energy to cool down, and take longer to do it. It will, therefore, be a better insulator. A low Cp means gas “heats up quickly” and “cool down fast”, it gives energy away easily so it is a poor insulator.

For nitrogen and oxygen, the Cp is very similar and is approximately 1.31 W/1ºC
For helium, Cp = 0.93 W/1ºC

The heat capacity of a mix is calculated considering the fractions of the gases in the mix.

Let’s look at three examples; one with air as a bottom mix, another with heliox, being radical to prove our point and the last with trimix.

Example 1: A diver has an RMV of 20 liters per minute. He is breathing air at 2ºC and at 50-meter depth. What is his lung thermal loss?

Thermal loss = 1.31 x 0.8 (38 – 2) x 20 x (6/60) + 10 = 85.5 W

Example 2: A diver is diving to 80 m with a 10/90 heliox mix at 2ºC. The mix heat capacity is (0.10 x 1.31) + (0.90 x 0.93) = 0.97 W/1ºC. What is thermal loss?

Thermal loss = 0.97 x 0.8 (38 – 2) x 20 x (9/60) +10 = 93.6 W
This same example using air would yield a result of 123.2 W.

Example 3: A diver is diving to 80 m with a 16/40 Trimix at 2ºC. The mix heat capacity is (0.16 x 1.31) + (0.40 x 0.93) + (0.44 x 1.31) = 1.16 W/1ºC. What is thermal loss?

Thermal loss = 1.16 x 0.8 (38 – 2) x 20 x (9/60) +10 = 110 W

What conclusions would you draw?
The first, and obvious, is that helium does not cool you more than nitrogen when breathing, much on the contrary. Surprised? Helium will, however “feel colder” in your mouth as it draws heat faster, and mouth and throat have plenty of “temperature sensors”. But it requires less energy to warm up then denser gases do, like oxygen and nitrogen. On the other hand, it will cool you a lot if used inside your suit, as it passes on the heat it receives from body to the surrounding water faster. Divers in a saturation habitat will also cool fast if the gas inside the chamber is not supplied at the correct temperature due to the high thermal conductivity of He.
The second is not so clear; just how much is 110 W? Is it much?

In order to answer this, we need to look at some more data.

Thermogenesis – Metabolic Energy Production

The typical value for the metabolic thermal energy produced by the body at rest is about 60 W, and may be broken as follows:
Different organs: 30 W
Nervous System: 12 W
Respiratory muscles: 6 W
Different muscles: 12 W

Total: 60 W

Thermal energy produced under moderate workload can go up to 300 W. This would be the case for continuous sustained fin swimming – the same as a runner at 8 km/h. This energy production is due mainly to increased muscle activity. Notice the raised value for respiratory muscles.

Different organs: 30 W
Nervous System: 10 W
Respiratory muscles: 60 W
Different muscles: 200 W

Total: 300 W

This thermal energy output cannot be sustained for long. After two hours of continuous exercise, the energy output will fall to 125 W only. It would be hard however to find an actual example of such extraneous dive. Gas consumption, or RMV, gives a far more useful indication of thermogenesis levels:

8 L/min (at rest) 100 W
20 L/min (bottom) 250 W
10 L/min (deco stops) 125 W

Now, if you recall, our heliox dive above represented a respiratory heat loss of 110 W. If we would consider an RMV of 20L/min, producing 250 W, we would still have a positive balance of 140W!
But are we not forgetting about body heat loss through the skin?

Coetaneous Thermal Loss

Skin will heat up gas inside suit by radiation and conduction. Convection inside the suit will transport heat to where it exits faster through suit. This makes it very difficult to generalize calculations as no two thermal protection configurations are the same, and no two persons are alike as to weight to body surface ratio or insulating body fat. However one can attempt to make a rough approach that can assist in proper planning for exposure protection.

Conduction has the more important role in heat transfer through a suit in diving. Fourier’s Law states that the amount of thermal energy passing from hot body on to a cold one, separated by an insulating layer, is proportional to the difference in temperature between the two bodies. The proportionality coefficient depends on the surface, nature and geometry of the layer, and is called Thermal Conductivity (W/ºC). The lower the value for thermal conductivity, the more insulating is the layer. If we consider our body to be the hot body and the outside water to be the cold one, we will have:

Coetaneous thermal loss (Q) = (T1 – T2) / (1/H1+1/H2+1/H3+…)


Q: Amount of heat
T1: Temperature of hot body (ours)
T2: Temperature of cold body (water)
H1: Thermal Conductivity of layer 1
H2: Thermal Conductivity of layer 2
H3: Thermal Conductivity of layer 3

Some examples of thermal conductivity values for different insulating layers are:

Air boundary layer 8
Periphery body fat (big guy) 15
Periphery body fat (regular guy) 30
Periphery body fat (thin guy) 50
Water boundary layer (almost still) 70
Water boundary layer (moderate current) 300
Polypropylene mountain 1st layer 400
Polar fleece 10mm thick 7
Polar fleece 7,5mm thick 10
Polar fleece 5mm thick 14
Polar fleece 10mm + Argon 4
Polar fleece 10mm + He 30
Neoprene 7 mm 20
Neoprene 5 mm 30
Neoprene 4 mm compressed 40
Neoprene 2 mm crashed 80
Trilaminate 300

Convection is defined as heat transport by fluid movement and can be used in our model as being a boundary layer of very high conductivity. It will be more important in a loose membrane suit than in a tight-fitting neoprene dry suit. Wetsuits can be treated the same as an extra “body fat” layer as they have similar values for heat conductivity, as long as they are tight fitting. Certain fiber underwear will allow for excessive convection and thus have high conductivity properties. The more gas circulation is restricted the better the insulation properties. Drawing sweat moisture away from the body will prevent that moisture from evaporating in contact with skin and thus reducing further cooling. Some fibers can accomplish this, however keep in mind that outer intermediate layers must allow water vapor to reach the inner wall of the suit and condensate there. Some “insulating underwear” have impermeable outer shells, that prevent this from happening and the inner fibers will become saturated with condensed moisture reducing insulation properties.

We can now calculate the thermal loss for the following example.

Example 1: A diver is 1,75m tall and weights 72 kg. He uses a trilaminate dry suit and a 7.5 mm thick overall polar fleece underwear. He uses air as suit inflation gas. The water temperature is 10ºC and there is a moderate current of 1.5 knots. What would be the expected through skin thermal loss?

Q = (38 –10) / ((1/50) + (1/300) + (1/10) + (1/300) = 221 W

Let’s summarize our findings

Respiratory Thermal loss = 110 W
Coetaneous Thermal loss = 221 W
Total Thermal loss = 331 W

Thermogenesis – Total Thermal loss = Thermal Balance

+ 250 W – 331 W = – 81 W

OK, now we have what we need to draw some conclusions:

1st: during a dive to 80 m, under the conditions given, the diver is loosing 331 W
2nd: during the same period he is only generating 250 W
3rd: this means that the balance is a deficit of 81 W

You can work out more precisely the thermal balance by calculating for the different phases of a dive on a specific profile and decompression schedule.

What are the consequences of our findings?

Research data shows that decrease in core temperature in degrees centigrade per hour can be calculated:

Cooling (ºC/h) = (Thermogenesis – Thermal losses) / Body Weight

So a diver with a body weight of 72 kg would experience a decrease in core temperature of 1ºC in only 53 minutes. A typical total dive time in trimix dives will last longer, this is a serious hypothermic condition where a diver can start suffering from poor judgment, uncoordinated movements, apathy, shivering and inefficient breathing pattern. Although this is a plausible scenario and it does occur, it is also true that the organism will react to the heat loss by raising metabolic production of energy – thermogenesis – to maintain core temperature at 38ºC. But we also know that it cannot do it for long, maybe for one more hour. On the other hand, the calculations above are just a rough approach to reality.
Thermal losses are difficult to quantify and are generally higher than the values found. It does not matter whether you dive in cold water in a drysuit or in tropical waters in skins, the heat deficit is still very much a risk in deep diving. During deco stops water may be warmer and RMV lower but you are breathing heavier gas, so the loss is still significant. You will tend to achieve thermal comfort for the temperature of the water you dive in, but respiratory thermal losses will often be overlooked. Also, consider that hypothermia is cumulative and that repetitive multi-day exposures will eventually overwhelm your body’s ability to cope.
As a last remark, think of the consequences of a ruptured dry zipper, neck or wrist seal at the end of your bottom time. If you use a membrane suit in cold waters you are in for trouble. Your insulation will simply be nil in a flooded suit. If you use a thick, tight-fitting neoprene dry suit you will be better off as, in case of flooding, it will function much as a regular wetsuit. Comfort for safety trade-offs can kill you. Proper maintenance of your exposure protection equipment is a must.

So, now you should understand why it does not deserve to be called a “cold gas” when inhaled from a scuba regulator as compared to air. These are good news.
Better news still, is that with CCR you lose even less heat through lungs. But that is another future subject to write about.

Dive warm, dive safe!

Article from the website


It is Valentine’s Day and you are looking for something fun and different to do.  Most couples have a nice dinner out, maybe a movie as well.  Why not find something out of the ordinary?  Be original and show your partner a little spontaneity in life – get certified and go diving.  In 1993, Arthur Aron, a professor of psychology at Stony Brook University, and colleagues published a study that found couples who spent time jointly doing new and exciting activities were more satisfied with their relationships.

Sally and I have been diving together for almost 5 years and we love it and these are the reasons why.



We get to learn to communicate in a different way – hand signals rather than talking.  Learning how to effectively communicate with your partner will strengthen the trust, honesty, and respect you have for each other and the relationship. Being able to take that communication to a whole new level while scuba diving can make your relationship that much stronger as a couple.  “Are you OK?’ “Do you want to go near that wreck?”  “Do we go deeper or shallower?”  “Did you see that shark?”  Yes, there is a sense of quiet while you are both underwater but the “conversation” doesn’t end – it simply carries on in a different “language”.


Planning toward common goals – from what you pack to where you go when you’re underwater to who will drive home after the dive because one of you is zonked out from the Bonine – is part of the fun.  Scuba diving doesn’t start the moment you get in the water; it starts the moment you decide to go.  We usually start planning a few days before on logistics like snacks, cash, and where we will go for lunch after the dive, but the afternoon before is when we whip out our checklists and pack our gear.  That can be a lot of fun as we do a double check on our partner’s equipment and our shared “save-a-dive” kit.  This is also a good way to understand your partner’s “needs and wants” and because of the planning and communication of what you hope to accomplish on these particular dives and what gear you need to do this, you can ensure both are going to have a great time because you have both planned and agreed on what to get out of this adventure.  Win-win.

Working through problems

Scuba diving gives couples an opportunity for problem-solving – with the post-dive debrief and how issues that cropped up will be addressed in the future.  Yes, the dive was great but it could have been better.  “Why did we swim against the current toward the end?”  “I don’t know, how can we avoid this in the future?” Relationships take work and problem solving together is a great way to work through those problems together as a team, not individuals.

Good Times

Scuba is fun and having fun together is imperative to any healthy relationship. Scuba brings you close to some really great marine life as well as historic artifacts like shipwrecks. The water is about 75% of the planet’s surface and, by becoming a scuba diver, you and your partner get to explore a world that so few people have been able to see with their own eyes. It also opens new adventures for you when you and your partner go on vacation.  Heading to Cancun for a quick vacation to enjoy a margarita on the white beach? Take a morning and visit MUSA, the underwater museum with over 500 permanent life-sized and monumental sculptures.   Heading to Hawaii on a weeklong getaway? Take a night dive on the Big Island and explore the magical dances of the giant manta rays hovering over you as they come into the reef to be cleaned by the Hawaiian cleaner fish.


One of the best things about being in a relationship is sharing adventures and experiences. One of the best moments immediately after the dive is getting out of the water and yelling, “OMG, OMG…did you see that turtle swim right by me?”  “Are you kidding me? I think I got an awesome picture right as it swam above your head!” Yes, scuba diving is fun but sharing it with someone special makes it so much better. And in the end, it doesn’t have to be just your partner. If you have children age 10 or older, they can get certified too and you can make it a family thing.

It doesn’t matter if your relationship is new or old, going great or sorting through some ups-and-downs, scuba diving will strengthen your relationship in ways that a week of bingeing Better Call Saul won’t be able to do. Increasing your communication with your partner, enjoying planning an activity together, finding the benefits of problem solving as a couple, having fun doing what few people do regularly, and then sharing that fun is a great way to spend time on a Valentine’s Day weekend, honeymoon, or any time you want to spice up your lives as a couple.

If you aren’t certified already, get started today.

By Cris Merz and Sally Camm

Material from website 


Diving 10,000 Year Old Ice

There is a very old dive site that has just been floating around waiting to be discovered…

Iceberg Scuba DivingAsk the average scuba diver what they think of when someone mentions ice diving and chances are good they’ll tell you about diving under the winter ice cover of a freshwater lake. But did you know you can dive ice in the summer too?

Every year it is estimated that as many as 50,000 icebergs calve off the glaciers of Greenland to start their long journey south driven by ocean currents. A few hundred travel down the North Atlantic coast of America and make it as far as the island province of Newfoundland. The most famous got in the way of the Titanic 100 years ago (April 1912); and the stream of berg’s since that historic collision has grown stronger in recent years thanks to global climate change.


The process of carving goes on year-round but the best time to see Newfoundland (or Atlantic) icebergs “in person” is in the summer, and one of the best places to find ones that are “safe” to dive is Conception Bay, near that Canadian province’s capital city of St. John’s.

“Safe” of course is an entirely relative term in all types of diving but most certainly in this particular flavor of adventure-diving. An iceberg is a dynamic entity; constantly moving, shifting, stressing and straining. Rolling and splitting are two of the constant threats presented by a huge chunk of frozen fresh water floating in a slightly warmer flow of salt water – and gradually melting away. Of course, these events can be disastrous for anyone close by, whether on the surface or underwater. Because of this and other factors, diveable bergs are bergs that are grounded. These are sometimes called Ice Islands.

Iceberg ScubaGrounding? Let me explain. There is no such thing as an average Newfoundland iceberg. Some are the size of a football stadium, and some look as small as a garden shed (see table), but what they all share is that approximately ninety percent of their bulk is “hidden” underwater. What we see floating is just the tip of the iceberg (sorry; couldn’t resist the pun). As air temperatures effect it – making it melt and crack due to changes in surface temperatures and internal pressure – a free-floating berg is always at risk of turning over or calving off mini-bergs of its own.

You might say that the berg is constantly changing its buoyancy and trim! Only when that hidden portion of the berg bottoms out on the ocean floor is there ANY opportunity to partially manage these risks.

However, few icebergs are held fast for long. As their bulk and mass gradually lessens, buoyancy changes and ever-present currents and tides will tend to push it along, often dragging its way through the seabed. Many berg divers check out this Ice Scour or Gouging – given depth limits – before getting close to the body of the berg. This is an indication of how long the berg has been grounded, and in some part, how it has behaved during its time as an ice island. Also, since the seabed in Newfoundland is home to all manners of cold-water creatures, the gouge often uncovers hidden critters and can attract larger predators to an open feast — take a camera!

Once a berg is confirmed to be grounded, divers usually submerge at a safe distance and swim toward the iceberg. This is one of the most unique experiences. Remember, an iceberg is fresh-water, perhaps more than 10,000 years old. It is pure and unsullied by mankind. As a diver closes in on its walls – which incidentally have the appearance of a multi-hued abstract sculpture – she will pass through the meltwater zone, where seawater and freshwater mix. Her buoyancy will change and she will experience passing through a distinct halocline. Also, the quality of sunlight or daylight will change, and it is not unusual for the visibility around a berg to be “virtually limitless.” The ice itself seems to glow from transmitted sunlight and the berg’s walls will shimmer with countless shades of blue from pale aqua to deep violet.

It will be, all in all, an unforgettable experience.

Size Category Height Length
Growler Less than 1 metre (3.3 ft) Less than 5 metres (16 ft)
Bergy Bit 1–5 metres (3.3–16 ft) 5–15 metres (16–49 ft)
Small 5–15 metres (16–49 ft) 15–60 metres (49–200 ft)
Medium 15–45 metres (49–148 ft) 60–120 metres (200–390 ft)
Large 45–75 metres (148–246 ft)       120–200 metres (390–660 ft)
Very Large Over 75 metres (246 ft) Over 200 metres (660 ft)

Data supplied by International Ice Patrol

Iceberg Diving


Often an iceberg will be surrounded by small chunks of calved ice (Growlers or smaller). If possible, collect one or two of these and use them in your cold drinks (in Newfoundland, this might be an after dive drink of Screech). When berg ice melts, it makes a fizzing sound called “Bergie Seltzer.” This sound is caused by escaping air originally trapped and then compressed as prehistoric snow layers became glacial ice.


Iceberg diving is great for advanced divers, equipped and experienced in cold-water diving since even in summer, the water temperatures at depth in Newfoundland hover only a few degrees above freezing. Divers with a sense of adventure and a yen for something out of the ordinary are also recommended.

There are several SDI/TDI instructors working in Newfoundland; to find out more about adventure diving, contact them through our website 

To take the first steps to iceberg diving in Moscow

Material from website 



Much of the advertising one sees for diving involves warm water and divers in swimsuits or thin wetsuits. It can be a bit of a shock to those divers who were certified in warm water to make a pilgrimage to a cold water location. For those of us who dive and teach in much of the northern hemisphere, talking about the differences is much like talking about how to choose a mask.

We are often asked about the differences between diving wet and diving dry. Other than the obvious answer – “you don’t need to dry anything but your hair after the dive” – there are some key differences.


1. Warmth.

This is probably the most important reason to decide to dive dry. You know that neither a wetsuit nor dry suit actually keeps you warm. What they do is slow the amount of heat loss. Wet suits do this using a layer of neoprene and a thin layer of water trapped between that and the skin. Dry suits use air and a combination of undergarments. No water to take heat away if a seal is lost and allowed to flush through the suit. With drysuits you can add layers of insulation to slow the loss of body heat.

2. Buoyancy.

Wetsuits compress with depth and lose some of their inherent buoyancy. Dry suits allow the diver to add air and compensate for the increased pressure at depth. As the wetsuit compresses, it gets thinner and loses insulating capacity. The dry suit does not.

3. Weighting.

Once a diver has become proficient with a dry suit, over-weighting is not as much of a concern as it is with a wetsuit. As a wetsuit loses buoyancy at depth, a diver can become seriously over weighted due to suit compression. With a dry suit, the amount of buoyancy the suit offers stays more or less constant since the diver has the means to adjust for the increased/decreased pressure.

4. Varying conditions.

A large benefit of a dry suit is the ability to use the suit in various conditions. A wetsuit does not offer the flexibility of a dry suit to add or subtract undergarments to suit the water/surface conditions. Many divers use their dry suit year round, from warm water locations to under the ice in winter.

5. Purchase cost.

At one time dry suits were prohibitively expensive for the average diver. One could purchase several wetsuits for the cost of one dry suit. They often had to if diving in a wide range of water temperatures! With the introduction of new materials and manufacturing competition, a quality entry level dry suit can be had for roughly the same price as a higher end wetsuit. By varying the undergarments the diver can also avoid having to buy several different thicknesses of wetsuits. One dry suit will work in numerous environments.

6. Cost of ownership.

Once a diver buys a wetsuit there is very little maintenance other than proper rinsing. Dry suits require seals to be replaced, leaks attended to, boots or socks replaced, and maybe even the zipper. These costs may be offset by the life of the suit. Dry suits, with proper care, can last 15 – 20 years or more. This is using the suit on a regular basis- say 100 dives a year. A wetsuit seeing that much use may last five years. In the long run, a drysuit may actually be less expensive. Dry suits often hold their value for resale. Used wetsuits get tossed. Used dry suits are sold to offset the cost of a new one!


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By Jim Lapenta


Underwater Navigation: I Want to go Home!

As an SDI/TDI Instructor it has come to my attention that some divers possess less than optimal skills related to underwater navigation. The benefits of developing these skills should not be underestimated.

Underwater navigation encourages the new diver to improve their skills overall, adds to their confidence level, and increases their general comfort. We should not look at underwater navigation as simply a course. It is a way to improve every aspect of every dive experience. Being able to return to your starting point utilizes more than just a compass, line, or a few features. The diver is required to use effective communication, good dive planning, buddy skills, buoyancy control, and gas management.


A good class will place heavy emphasis on the subjects noted previously as well as basic navigation skills. Use of a compass, natural navigation, use of lines and reels, documenting a site, and awareness of hazards all should be included. It should allow plenty of time for practice and use small goals to promote success; rather than large ones that result in frustration. A good navigation course adds to every facet of a diver’s skills. It is one of the most important classes a new diver can take.

So what are the results of a good course and practice of the skill sets?

  1. Increased Safety – Resulting from proper planning, effective communication, and the use of actual buddy skills. This comes in the form of actual physical safety as well as mental and emotional well-being. If you know where you are and how to get back to the entrance or boat, your stress level is greatly reduced. Stress can lead to panic, and panic can kill.
  2. Better Air Consumption – Knowing your course and needed pace allows you to relax and not exert excess energy. Exertion increases air consumption. A slow, relaxed, course and speed may allow you to spend more time at the desired goal of the dive.
  3. Better Buoyancy and Trim – Successful underwater navigation relies on good buoyancy and trim to stay on course, do not silt up the area, stay in good buddy position, and make effective use of navigation tools.
  4. Better Buddy Skills – You have to be in close and effective contact with your buddy to navigate as a team. Sharing the tasks of monitoring course, depth, time, air, and features reduces the load on each team member.
  5. Better Communication Skills – If you can’t communicate effectively with other divers everyone on the dive suffers. Using slates, wet notes, lights, hand signals, and proper surface communication skills before the dive is vital to success on any dive. Underwater navigation requires you to use all of these and polishes the skills.
  6. It’s Very Cool and Fun! – Rarely have I met a person, diver or otherwise, who is not impressed when I talk about swimming a site and making five or six course corrections, using a compass, the features of a site, and if the vis is bad – a line and reel or spool, to find my way back to within a couple yards or even feet of where I went in. Students who complete my underwater navigation class are often in awe of their own abilities. It increases their confidence and sense of accomplishment as well as giving them a feeling of security.

Underwater Navigation is not just about getting out and back. It’s about doing so safely, confidently, and in a manner that is effectively working on all your dive skills. At the same time, it’s a lot of fun to do!

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By Jim Lapenta



Around the world, individuals, friends, couples, and families often look for new and exciting activities. These activities may involve sky-diving, hiking, camping, or even game night at the house. Certain activities may even fall into a category some colleges choose to refer to as “life-sports.” Life-sports are activities that a person can learn, develop, and perform throughout a lifetime. One such activity is scuba diving. Scuba diving is a sport that allows people to first learn about the sport, and then carry education and experience down various pathways of adventure. So the next time you or your companions are considering trying something new, take a moment and look into what it takes to become a scuba diver. You may find the one new activity that keeps you happy and smiling for many years to come. Here are seven reasons why you should consider becoming a certified scuba diver.



Often, when people try something new, they hope it carries them to unique places and allows for interesting experiences. Over 70% of the Earth is covered in water, so the odds are pretty good that scuba diving may allow you go to new places. Almost any place a person travels will have some sort of water-filled environment that will allow for a little adventure. Similarly, scuba diving is a sport that allows a person to explore new places as that person continues his or her education. For instance, if a diver learns to safely dive with mixed gases, that diver may choose to venture to wreck sites at deeper depths. Or if a diver partakes in cave diving classes, he or she may be able to adventure in the watery passage ways below the ground’s surface. Essentially, scuba diving opens the doorway for adventure and excitement, and with more education, this adventure never really ends.

2. Relax and Eliminate Stress

Every day as we all walk around, we experience the effects of gravity gluing us to the ground. Scuba diving changes that daily weight on our shoulders. Under water, divers get the opportunity to experience a near weightless environment where there are no cellular phones, television shows, or office meetings. Instead, divers hear the sounds of moving water, aquatic life, and peace. Many divers view scuba diving as a release from the normal work world. Every time they submerge below the surface, the only thing in the world is the water and the current dive. For this reason, if someone is looking for a new activity or hobby, scuba diving may be the perfect release from the daily grind.

3. Explore New Places

As mentioned earlier, roughly 70% of the world is covered in water. Scuba diving is a sport that people can use to go places and see things that they have never before experienced. The underwater world is one that will open up to a new diver. New coastlines, reefs, lakes, rivers, and springs will be available to experience in a whole new way. No longer does a person need to look at the water from the surface, or swim down with snorkeling equipment for a quick glance. Now, a diver can take time to see what is down there, and develop new experiences.

4. See Creatures Outside of an Aquarium

Many people have only seen aquatic life from the side of a boat, at the end of a line, or walking through an aquarium. Scuba diving allows a person to delve into the realm of aquatic life and see interesting new creatures in their own backyard. Fish, sharks, rays, eels, and hundreds of other creatures can be seen in their natural environments. As you travel the world, new and interesting creatures may even be visible in each new place. Scuba diving takes the creatures and the visitor outside of the aquarium and allows the visitor to really see how marine creatures exist in the underwater realm.

5. Develop New Friendships

No matter where scuba diving may take you, divers are never alone. Scuba diving is a unique sport in which the participants always seem happy, excited about the most recent adventure, and willing to share stories. For this reason, at the end of a diving day, divers can often be found together at the local watering hole, restaurant, or by the water waiting on tomorrow. The scuba diving community is one in which new friends can be made and new adventures can be shared.

6. Get Outdoors

One of the greatest things about scuba diving is that the sport requires people to get outdoors and get wet. Whether you are exploring a new cave in a jungle somewhere or simply visiting the local quarry, scuba divers get outside and exercise. This sport is one that encourages participants to be fit and to get out of the house. Whole families can get outdoors and spend days enjoying local dive sites or simply discovering new places to get wet.

7. For You

Lastly, scuba diving is sport you should take on for you. Scuba diving can take you to new places, show you new things, help you make new friends, and get you outdoors. Despite these great advantages to scuba diving, you should only take on this sport if it is something that excites or intrigues you. Do it because you love the idea of sinking beneath the waves and doing something that few people can. Along the way, you will realize that a life-sport of this type will keep you excited and happy, but do not do it just because someone tells you to. Instead, look into what it takes to become a scuba diver and take the plunge because you want to be a diver.

There are many reasons a person may choose or desire to become a certified scuba diver. The best way to better understand the sport is to visit your local dive shop and talk to the staff about what it takes to become a diver, and how they can help you begin your new adventure. Just remember that scuba diving will take you on an interesting adventure should you allow the sport into your life, and it just may become something you really love to do with the people you care about.

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by Dr. Thomas Powell


How To Pack Your Scuba Diving Gear and Equipment for Travel

Packing for dive travel presents a conundrum. Spread before you is a vast arsenal, each piece essential to fulfilling your travel fantasy. To bring along all of the regulators, wetsuits, computers, masks, fins and camera equipment and other scuba gear necessary for a serious dive mission (along with their backups and batteries), you’ll need a fleet of roller bags — and a Sherpa. But your airline has strict limits on the amount, size and weight of luggage, and violating its limits can add up to an astronomical cost. How can you make it all fit?


It might seem beyond the boundaries of physics to bring it all along, but savvy travelers have developed strategies, techniques and tricks for maximizing baggage allowances, avoiding ludicrous fees and making sure it all gets to where it’s supposed to be in one piece. Professional photographers and technical divers are some of the best of our breed at subversive packing, schlepping easily damaged high-tech tools to the most remote destinations on the planet.

Here’s advice from four experienced dive travelers who know how to get all of their gear around the world safely without breaking the bank.


Every airline is required to publish its baggage allowance and overage charges so travelers know what they’re getting into. Professional underwater photographer and rebreather enthusiast Chris Parsons, who has been known to fly with an excess of 250 pounds of gear, starts every trip with the fine print on airline websites. “Although it is tedious, I try to read the airline rules so I have an idea about how best to pack,” he explains. “Having frequent-flier status on an airline helps too. For example, I get two free 70-pound bags on one airline three for international travel.”


Airline ticketing representatives and Transportation Security Administration (TSA) agents control your destiny in many ways. Smiling and being cordial makes a big difference to people who deal with irate travelers on a regular basis. “I try to be extremely nice at the checkpoints of all airports because I know they are doing their job and do not understand what all of our equipment is,” says underwater videographer Annie Crawley, who learned an important lesson in public relations on a return trip from Mexico to home in Seattle. “The TSA officer decided my backpack carryon with all my camera and computer equipment was too large to go through the security checkpoint and wanted me to check it in,” she says. “I ended up getting the pack through, but it taught me a lesson about the power of gate agents and TSA officers.”


For rebreather instructor and underwater photographer Doug Ebersole, managing all of his gear on the road “is almost impossible unless you get creative with your carry-on luggage.” Laptop, camera, lenses and dive computers ride on his back and in the cabin, and the rest of his kit goes into the hold. Kevin Palmer, a pro photographer and manager at Reef Photo & Video, dons the most pocket-laden vest he can find. “The best hang down to your thighs and have 12 to 20 pockets,” he says. “If the dreaded carry-on weigh-in occurs, these vests can easily hold 10 to 20 pounds of stuff in the expandable pockets. Yes, you will look like John Candy on a fly-fishing trip, but nobody said diving was a glamour activity.”

"Reusable Ziploc bags are essential for organizing items, and the 2-gallon version can vacumm-seal clothing."


For the sensitive equipment you absolutely must check, think protection above all else. Says Palmer, who once sacrificed his clothes for a bag with his camera: “Most travel bags for divers are soft-sided, so making a protective ‘frame’ is really helpful. Fins are great for this, as are shoes placed sole-out on the ends of the bag.” He also uses soft items such as wetsuits and clothing to create perimeter protection “from the full-on airline-handler assault. Socks make great padded sleeves for items like dive computers and camera lenses,” Palmer continues. “I usually reserve my 5 mm wetsuit for any backup glass ports I might bring for my underwater camera housing, which rests safely in the protective framework I have established while clothing fills in the gaps.”


Don’t overlook your kitchen or workshop. Ebersole packs breakable items, such as the heads of rebreathers, individually in Tupperware and puts the containers in his luggage. “It doesn’t add much weight and protects the items,” he says. For Palmer, “ Reusable Ziploc bags are essential for organizing items, and the 2-gallon version can vacuum-seal clothing.” Plus, “Zip ties are indispensable. They are the perfect TSA-approved disposable lock for your check-in bags. I always bring a big handful in the pocket of one of my bags.” (Don’t forget a TSA-approved cutting tool, in case you have to open them.)


Airline baggage rules are constantly changing. The generous weight limit on a past trip will likely be lower today, so there’s no substitute for communicating with staff, asking the right questions and — in some extreme cases — simply pleading for mercy. “Many airlines are now weighing and requiring approval for carry-on bags, so I take a different approach,” says Crawley. “If I know they are checking carry-on bags for weight, I open up my backpack or hard case and show them the equipment inside. To date, I have been greeted only with kindness and understanding.” Palmer employs a similar strategy. “Polite resourcefulness can almost always get you through. Start with, ‘Yes, it is a little heavy, but this is packed with computers and photo gear. Don’t you have a special allowance?’ Fifty percent of the time it’s all you need to say. The other half of the time requires a little planning ahead. I always carry a lightweight nylon fabric bag stuffed into a pocket of my carry-on. In a pinch, I can whip it out and offer to transfer some heavy items (batteries, a regulator, etc.) into the additional bag. Often the airline employees are just trying to get a bag below the authorized weight limit out of fear of losing their job and will be most grateful for your improvised solution.


By Eric Michael 









Hello, and welcome to the world of diving!  Regardless of how new you are to the sport, I’m sure there are some questions that are still running through your mind.  Your open water course just can’t cover everything there is to know and I’m here to provide a few answers.  I have seen numerous “10 tips for the new diver” articles on the web and can’t help but notice that they all are very useful, but incredibly similar.

Here are my 10 not so typical tips for the recently certified.  They have been developed through my experiences as an instructor in the field, numerous conversations with other instructors, and, most importantly, the polling of divers at many levels as to which topics were the most elusive to them.


  1. Purchases – Buy a computer first.

Once you are certified, you will want to start considering which gear to own.  I would highly recommend looking to a personal dive computer as your first investment.  Dive computers have become extremely affordable and are your best friend in dive safety!  Additionally, with their small size, they are a breeze to travel with and having your own guarantees that you will be diving with a unit that you understand how to use.  Also, in many locations, an array of dive gear will be available for rental, but unfortunately computers often don’t make the list.

  1. Skills – Show your compass some love.

Compass navigation is an integral skill for divers of every level.  Unfortunately, this skill is often only briefly touched on in many open water courses.  Don’t wait until your navigation specialty course to become familiar with your compass!  Take a compass with you on every dive and pay attention to which directions you are going and which directions landmarks are in.  They can seem like an intimidating piece of equipment at first, but don’t overthink it; use basic directional headings to gain your bearings and ensure you are swimming in the right direction.  Try carrying it around with you on land too for some extra practice.

  1. Mindset – The best dive is the one you come home from.

This phrase has always resonated with me.  It may sound pretty dire at first listen, but it is a blaring truth for all levels of diving.  Let’s look at the reality of things; we are entering an environment in which we are not naturally adapted to in any way.  Without our equipment, we cannot effectively see, move, or breathe!  The phrase is not here to scare you, but to remind you to respect the foreign environment you are entering, keep up with your training and gear, and never fall victim to the “justs” – It’s not JUST a 20 foot dive, it’s not JUST a small equipment malfunction, it’s not JUST this once.  Falling into these habits on the smaller dives increases the likelihood of being okay with poor practices on the bigger dives.  At the end of the day, no dive is worth losing your life over.  We’re all in it for the enjoyment of this wonderful sport, so let’s keep it happy and healthy.

  1. Continuing Education – Log your damn dives!

This is one of my personal pet peeves and a habit that needs to be formed from the beginning.  If you have not logged all of your dives at this point in time, then go get your logbook right now and make it current; you are not allowed to continue reading until it is done!

Updated?  Perfect, let’s continue!  Keeping an accurate and up-to-date logbook posts many benefits for the diver, especially in the earlier stages of diving. One of the most important benefits is proving experience.  Many of the courses that you will participate in will require a certain amount of experience to be shown before starting the course.  Without your logbook as verification, you are as good as freshly certified.  So please, for heaven’s sake, LOG YOUR DIVES!

  1. Community – Get involved and pay attention to other divers.

As nasty as we can seem to each other online sometimes, most divers are pretty friendly people when they aren’t behind the keyboard!  Diving is very much community based and, once you are in, it really is an awesome community to be a part of!  Divers are usually very passionate about what they do (which is where some occasional tension can come from), but in every diver’s heart lies the desire to see the sport grow and witness the spark of scuba in a new diver turn into an unstoppable wildfire.  One of the best ways to enhance your diving experience is to join your local gatherings of divers and absorb everything you can from them.  Becoming a great diver is all about experience and unfortunately you lack that right now.  Take full advantage of what the community is willing to pass on and you will certainly thrive while making some great friends along the way.

  1. Preparedness – Always check your gear.

Create a checklist, don’t wait until the last minute, do it yourself, check it at home, and check it again before the dive.  I have witnessed countless missed dives, close calls, and issues underwater by students and professionals alike resulting from ill-preparedness.  Unfortunately, it took a scare to make many of these individuals realize the importance of being thorough with their equipment.  When we place so much reliance on our equipment, it is paramount that it is functioning properly and that all of it makes it to the dive site!

  1. Moving Forward – You don’t have to be perfect, but be mindful.

You are a new diver, everyone knows it, and there is nothing wrong with that.  Nobody is going to expect you to be a pro right off the bat.  Experience must be built, questions asked, and mistakes made.  Never fear judgment for taking some extra time or needing clarification on a topic.  The important thing to remember is to be mindful of your skill level and never lose the desire to improve!  Continuing education and keeping an honest eye on your own performance will lead you to success!

  1. Reality – Your buoyancy sucks.

It just does.  Don’t take it personal, so did mine.  In fact, I didn’t even start to really understand what neutral buoyancy was until I had close to 50 dives under my belt.  Even if you are starting to get it much sooner than I was (which you probably are), don’t ever forget that great buoyancy is a habit, not a skill.  It requires constant monitoring and practice and is NEVER absolutely perfect.  Remember, neutral buoyancy is about more than looking like a total boss in the water; it poses many benefits to the diver and the environment.  It doesn’t have to be all business either; have some fun with it!  Grab a buddy and play some skill building games or get in front of a camera to pinpoint which areas need improvement. Whatever method you choose, keep up with it – it is worth the work!

  1. Lifestyle – Pump the breaks, assuming that you remember how to use them.

Diving is a culmination of skills that should be mastered and maintained, not a checklist to be blown through.  As a new diver, you probably want to take every course available and move up to the advanced levels as soon as possible.  I whole-heartedly encourage you to do so, but keep in mind that each course you take relies on the understanding of any prerequisite courses.  Take the time to give more practice to what you have already learned before advancing.  Having a thorough understanding of the basics ensures comfort in the water and that they are second nature when you start becoming task loaded or run into a sticky situation.

  1. Computers –Understand your NDL.

The no decompression limit is one of the most important functions of your dive computer.  It is the number that counts down throughout your dive and that you don’t want to hit zero! Exceeding your NDL will enter you into decompression diving – something that is much past your current level of training and can potentially put you at a significant risk.  If you are uncertain of how and why it works, please seek further info or consult with an instructor before your next dive.


By Jesse Iacono


How to remedy legs cramps under water

You’re swimming along, just enjoying the dive.  Suddenly, out of nowhere, it strikes.  It feels like a ball of fire is consuming your leg as the searing pain hits.  Shark attack?  Nope.  Eel bite? Still nope.  This special agony can be a common issue for divers – the leg cramp.

Why Me?


So why do we occasionally suffer from leg cramps?  And why are some people afflicted on a regular basis while others may never experience this joyful event?  In simple terms, a muscle cramp is simply an involuntary contraction of a muscle that doesn’t relax.  Muscles typically alternate between contracting and relaxing. When a muscle involuntarily contracts, it is said to be in spasm.  If a spasm is hard enough and lasts long enough, it will become a cramp.

There are numerous issues that may trigger cramping, especially in the foot or calf, these include:

  • Improper fin fit – too tight squeezes your foot inhibiting muscle function and blood flow
  • Improper boot fit – same reasons as above
  • Fin straps too tight – pressure on the Achilles tendon causes calf muscle tension
  • Wetsuit too restrictive – impairs range of motion
  • Improper finning technique – more on this in a moment
  • Improper fin selection – more on this later as well
  • Muscle tightness – tight muscles are more prone to cramping
  • Hydration – once thought to be the  main cause of cramping however, recent studies show this may not be the case, but that it may contribute
  • Poor mineral nutrition – certain electrolytes like calcium, magnesium, and potassium play a role in muscle function and nerve signal transmission and are also thought to have a role in cramping
  • Cold conditions – exertion in cold conditions tends to lead to cramping easily

Finning, Finning, Finning…

Specifically in diving, we often see cramping of leg muscles due to improper fin selection, improper finning technique, and/or working the calf muscle beyond its endurance. Avoiding cramps entirely may not be possible, but we can do quite a bit to help lower the chance.  

Selecting a properly fitting fin with appropriate design features is a good starting point.  Foot pockets need to have enough room to allow the foot to move and flex without being loose enough to cause problems with retention of the fin or cause chaffing.  A foot pocket that doesn’t fit properly often leads to fins straps that don’t fit properly,putting pressure on the Achilles tendon.  This leads to calf muscle tension that can develop into spasms and cramping.

Fin stiffness is also a consideration.  

Divers should select a fin that provides enough stiffness for their preferred kicking style without being too stiff.  A diver that prefers the flutter kick will want a more flexible fin than a diver preferring the frog kick.  Your local SDI dive center can assist you in selecting the appropriate fin for your diving.

How we employ our fins can have the largest impact.  A diver employing poor finning technique (think bicycle kicks) is working their muscles hard for very little benefit, quickly working the muscle past its endurance and causing cramping.  More efficient flutter kicking could help avoid this, as can even more efficient frog kicks.  Sometimes just mixing up kicking styles on a dive can allow a group of muscles to relax a little while different muscle groups are employed in an alternate kicking style.  A proficient diver will learn several finning techniques so they can employ the best option in different situations.  You can check out some of the more advanced finning techniques  here.

Taming the pain

So what can we do when we get a cramp? Most new divers are taught how to deal with this by simply stretching the affected muscle and possibly having a buddy assist.  The idea here is to help the muscle relax instead of contract.

To stretch the muscle, you can begin by forming the figure four with the cramping leg by crossing your ankle over the opposite knee.  Reach down and grab your fin tip.  Then, extend the cramping leg while simultaneously pulling back on the fin tip.  Exert a steady gentle force to stretch the affected muscle,  you can even use the other hand to massage the cramp out.  The cramp may be severe enough that your buddy may need to assist you in stretching the affected muscle.  Just be aware of your buoyancy control so you don’t impact sensitive aquatic life or destroy the visibility.

If you know you’re prone to cramping, you can try to stay better hydrated.  Stretching prior to diving may also help.  Developing and maintaining a proper level of physical fitness for the diving you wish to do will go a long way to limiting cramps.  And if all else fails, employ the old trick of drinking pickle juice – it’s thought that the salty, acidic taste tricks your body into relaxing the cramping muscle.


By: Brian Shreve  (with contributions by Jordan Greene)



Whether you’re a prospective, or new, dry suit diver – you’ve likely heard a few outrageous stories about the potential challenges that come with diving a dry suit, specific to body position or “trim.”  If you’re not sure what we mean by body position or “trim” while diving chack out this article. 


So, maybe you’ve heard once you dive dry, “there is no way you can reach your valve(s)” or a dramatic story of a diver having too much gas in their feet and rocketing towards the surface upside down.  Sure, each of these scenarios is possible but they can be easily avoided with a combination of a proper fitting suit, adjusting your tank position and weight placement, honing in on your dry suit diving skills and technique, and gaining more experience. In time, you can dive a dry suit just as easy as a wetsuit.

Before you break out the dry suit this winter, consider these tips and tricks to help dial in your trim while diving dry.

  1. Invest in a Proper Fitting Suit

As a diver who dives dry 90% of the time, I can honestly say a proper fitting dry suit is the best equipment investment I have made to this day. Like many divers, I started diving dry in a suit that was not fitted properly and found it to be a little challenging.  Everyone is shaped different and few people match up to an “out of the box” suit for a perfect fit, and there is nothing wrong with that.

When you’re ready to make the investment, I urge you to seriously consider working with your local dive shop to find a suit that best fits your body.  If you can’t fit into a stock suit, go custom!

Diving a dry suit that fits you properly will make your future dry suit dives so much easier and comfortable.  It will allow you to manage less gas in your suit and make it extremely easy to vent gas when the exhaust valve is placed in the ideal position for your body. In addition, a proper fitting suit will allow you to place your arms out in front of you to hold that “perfect trim” position and give you enough freedom and flexibility to reach your valve(s) behind you.

  1. Tank Position and Weight Placement

Let’s start with tank position. Just like diving a wet suit, your tank placement can have a significant effect on your trim in the water.  Do you feel like you can’t get your feet up?  Try sliding the cam bands down on your cylinder just a bit or if you have floaty feet, try the opposite.  Doing so can create a fairly drastic shift in your center of balance by just moving your BC cam bands up or down a few inches.

On to weight placement. Weight placement is even more critical in a dry suit than diving wet.  This is primarily because you are likely to use more of it.  If you typically wear all of your weight on a weight belt or in a weight integrated system on your waist, adding the additional weight you need in a dry suit to this area could have detrimental effects on your trim and drag your hips down.  To counter this, consider using trim pockets (either built in or aftermarket pockets that weave on to your cylinder cam bands) to help distribute some of the additional weight further up on your body for better balance.

  1. Floaty Feet

One of the most common situations a new dry suit diver fears is having too much air in the foot pockets of their suit, going head down with feet up while making an uncontrolled ascent.  This is avoidable!

Diving a proper fitting suit can help reduce having excess gas trapped in your legs and feet area.  In addition, many modern suits have retaining ankle straps designed to keep excessive air from entering your boots if you don’t use a separate boot style shoe. If your suit did not come with ankle straps, you can purchase aftermarket “gaiters” or simply use bungee cord to help keep the excess gas out of your feet.  If you continue to have “floaty feet” issues, you may also want to consider switching to a heavier fin or go back to adjusting your tank position and weight placement.

  1. Buoyancy – BC or Dry Suit?

I realize this may be a sensitive area as many divers swear by one method or the other when it comes to buoyancy control while diving dry.  So the question is, to use the BC or dry suit for buoyancy?

Well, my goal with this piece is to discuss methods to dial in your trim while diving dry so with that in mind, I tend to lean towards the route of using your BC for buoyancy and adding gas to your dry suit only to offset squeeze and for warmth as needed.

Why you ask?  Having too much gas in your suit can make it difficult to maintain control and proper body position while diving; whereas having just enough gas in your suit will allow you to determine where that gas is placed to support better trim and control.

With practice and experience, managing your dry suit and BC will become second nature.  On the few wet suit dives I make each year, I find myself going through the motion of trying to add a small amount of gas to my suit when I get a little chilly, only to laugh at myself when I realize I am not in a dry suit. In time, diving dry can become just as easy as diving wet and the skills, such as adding and venting gas from the suit, will become second nature. My best advice on this, work with a qualified instructor and get out there and practice!

Proper trim in a dry suit can be a challenge in the beginning. Before purchasing additional equipment as a quick fix, allow time, practice and patience for your body to adapt to adding a dry suit in the mix.  Remember, tank and weight placement, along with a proper fitting suit are essential to dialing in your trim while diving dry. For more information or to find a SDI Dry Suit diving instructor click here!

By Lauren Kieren


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