Snorkelling Techniques

The following are techniques to make snorkelling enjoyable, safe and fun.

Clearing the Snorkel

Clearing the water in the snorkel after swimming below the surface is the main issue a snorkeller must deal with.

The principle is to blow the water out of the snorkel on surfacing, while keeping the face looking down into the water.

The best way to do this is by tilting the head at an angle as the head breaks the surface. This is best done by looking at the surface as the snorkeller surfaces. Then as the snorkel breaks free into the air, a quick blow from the lungs will clear the snorkel.

Doing this at an angle doesn’t require as much effort as when the snorkel is pointing straight up as the water in the snorkel is not as heavy.

Surface Diving With a Snorkel

There are two main ways to get underwater when snorkelling.

1.The pike, or duck dive. The snorkeller on the surface, bends in the middle so the head faces down; then the arms pull the body down. The fins don’t start kicking until under the water to prevent the wild thrashing of the fins on the surface.
2.The feet-first dive. First the snorkeller fins straight up so the body is high out of the water, then sinks straight down. Once under water, the snorkeller rolls into a ball, tucking the feet up until the head is facing into the depths. Again the hands pull the body down and the fins don’t start kicking until clear of the surface.
Ear Pain While Snorkelling

Ear pain while snorkelling is caused when a snorkeller descends creating a pressure difference across the eardrum between the outer and middle ear. This forces the eardrum to bulge inwards causing increasing ear pain until eventually the eardrum will burst.

Equalisation of the pressure difference is achieved via the eustachian tube that connects the middle ear and the throat. The tube must open to allow the higher pressure (in the throat) to flow into the middle ear.

The eustachian tube is kept closed by small muscles in the throat. To open these muscles, the snorkeller must yawn, swallow or move the jaw.

Sometimes opening the eustachian tube is not enough and a snorkeller may need to force air up the tube. The snorkeller pinches the nose and blows against the closed nose and mouth. This equalises pressure across the eardrum and is usually referred to as the ear “popping”.

Called the “Valsalva” technique, it is named after a scientist in the 18th century.

It must not be forceful as the eardrum can rupture.

Snorkelling in Tight Places

For some snorkellers there is temptation to swim through caves, under ledges or into wrecks. This can be fun and challenging, but there are risks involved.

•a piece of clothing could get caught;
•a serious knock on the head on a narrow space;
•or maybe an encounter with fire coral.
These risks can be minimised, but not eliminated, by having a snorkelling buddy watch over these activities.

Snorkelling Hyperventilation

A common practice for snorkellers is taking long, deep breaths (hyperventilate) just prior to ducking under the water. This can prolong the time on the one breath.

Hyperventilation increases oxygen and decreases carbon dioxide in the body. This is acceptable for a few breaths, however prolonged hyperventilation can reduce the carbon dioxide in the body to levels where the acid-base balance of the blood is disrupted. This is called hypocapnia and can lead to unconsciousness.

Snorkelling hyperventilation should be limited to just three or four breaths.

The above snorkelling techniques should lead to safe and enjoyable snorkelling.

Carbon Monoxide Poisoning and Scuba Diving

Carbon monoxide is a tasteless, colourless and ordourless gas formed by the burning of petroleum based fuels in combustion engines; and the burning of plastics, coal, and cigarettes.

How Does Carbon Monoxide Affect a Scuba Diver?

Red blood cells contain haemoglobin that attracts gases. Live-giving oxygen is the main gas the haemoglobin “latches” onto. However, carbon monoxide is also easily absorbed by haemoglobin; and binds to the haemoglobin around 200 times stronger than oxygen.

What this means for a scuba diver breathing from a contaminated tank, is that the blood can quickly become “overloaded” with carbon monoxide. This cuts out the oxygen and means the oxygen does not get to the body’s tissues where it is needed to make the cells function correctly.

The result is carbon monoxide poisoning.

Carbon Monoxide Poisoning Underwater

When a scuba diver is underwater with carbon monoxide poisoning, the haemoglobin may be overloaded with carbon monoxide and can’t absorb much oxygen. However, the increased partial pressure of oxygen at depth may result in enough oxygen in the blood to keep the cells oxygenated.

In this situation the diver can function, but when they ascend to a shallower depth, the partial pressure of oxygen will decrease. This will lead to the tissues being starved of oxygen and unconsciousness can occur.

A scuba diver with carbon monoxide poisoning will probably feel unwell while underwater, so should ascend as soon as symptoms occur.

How Does a Scuba Diver Get Carbon Monoxide Poisoning?

One the most common ways for a scuba diver to get carbon monoxide poisoning is from the scuba tank being filled with air contaminated with carbon monoxide.

This can occur if the fresh air intake pipe to the air compressor is next to a source of carbon monoxide, such as the exhaust of the engine driving the compressor.

In some situations, a well-meaning dive shop operator may have the air input pipe to the compressor outside in the fresh air. However, a car with its exhaust running might pull up close to the intake and its carbon monoxide may find its way into the tanks.

Careless location of a compressor’s air intake on a boat can also result in carbon monoxide from the boat’s engine.

How Does a Scuba Diver Avoid Carbon Monoxide Poisoning?

A scuba diver can reduce the possibility of carbon monoxide poisoning by having a quick check of the location of the air intake of the air compressor when getting a scuba tank filled at an unknown filling station.

This is especially important when on a scuba dive holiday.

As carbon monoxide is contained in cigarette smoke, a scuba diver shouldn't have a cigarette just prior to ducking underwater.

Symptoms of Carbon Monoxide Poisoning

The most common symptoms of carbon monoxide poisoning are:

•Cherry-red lips, cheeks and fingernails;
•Dizziness;
•Headaches;
•Staggering;
•Confusion;
•Paralysis.
Unconsciousness and death can result.

Treatment of Carbon Monoxide Poisoning

The first aid treatment for carbon monoxide poisoning is fresh air. This should be in the open deck on a boat; not inside the cabin or near the engine’s exhaust.

Pure oxygen should be administered, if available.

A check up at a hospital or doctor is always advisable for any diving related medical condition; even if the symptoms are mild.

Fortunately carbon monoxide poisoning is rare. However, its impact can be reduced by a scuba diver’s vigilance in being aware of the scuba tank filling station’s procedures.

Scuba Diving Tweed River, Australia's Gold Coast

Nearly every weekend, scuba divers can be found at the Tweed River dive site, either doing scuba dive training or simply enjoying getting under the water

Location of the Tweed River Dive Site

The Tweed River dive site is located on the northern bank of the Tweed River, about 500 metres from the river mouth. There is a car park and a large grassed area; perfect for gearing up and pre-dive briefing.

Access to the water is via short scramble over rocks then onto a concrete platform where the water laps at high tide. This concrete platform has been built over the years by various scuba divers and scuba dive schools and now provides an easy access and exit location

The GPS coordinates (Decimal Degrees) for the Tweed River Dive Site are:

-28.169644

153.549213

When to Dive at the Tweed River Dive Site

The best time to do a shore scuba dive at the Tweed River is on the turn of the high tide as the dive site is impacted by tidal flows. For a forty minute time underwater, entry should be about twenty minutes before the high tide.

Diving on the change of tide is also the optimum for the best visibility underwater.

Details on the Tweed River Dive Site

The Tweed River dive site is not known for good visibility. Its attraction is mainly for scuba dive training courses and an easy place to simply get wet on a scuba dive.

The maximum depth is around 40 feet; with visibility usually around 20 to 30 feet.

The ease of access makes Tweed River dive site especially good for initial training in night diving. The easy entry and exit, and gear up area means a night dive can be conducted in relative safety.

What’s to See at the Tweed River Dive Site

The Tweed River dive site has some unique aspects. For many years, an old bath-tub was a common feature at the bottom. Many divers in South East Queensland would have done basic training like mask clearing and buddy breathing around the Tweed River bath-tub.

Soft corals cover the rocks on the Tweed River bank. Schools of bream wander through the dive site, and the occasional octopus can be found lurking under rocks on the bottom of the river.

One diving activity at the Tweed River is to collect sinkers. The fish life attracts fishermen who cast their lines from the riverbank to try their luck. With the rocks on the bottom, there are many snags which means the hapless fisherman loses his or her tackle. This makes it possible to collect a large amount of sinkers for making into scuba dive weights.

Safety When Diving at the Tweed River Dive Site

Because the Tweed River dive site is in a river, there are always a number of boats in the area. This means a dive flag should always be used.

Some training schools will establish a stationery dive flag floating above their training dive. Divers have been known to drag a dive flag along as they swim; the dive flag floating above on the surface while they explore underwater.

Many experienced divers don’t like scuba diving at the Tweed River dive site as they claim it is boring and uninteresting. However, when considering the advantages of the Tweed River; such as easy entry and exits for shore diving, safe conditions and its location on the southern end of Australia’s Gold Coast, the Tweed River dive site is more than just a scuba dive training site.

Scuba Diving at McKenzie Jetty, Australia

The jetty was originally built in the early 1900s to facilitate taking timber off the island to the mainland. A timber mill was built on the island near the jetty and a small railway brought the trees to the mill to be processed and then onto the wooden jetty to be loaded onto ships.

The timber felling ceased in the early 1990s when Fraser Island was declared a World Heritage Area; and Mackenzie Jetty fell into disrepair.

Location of McKenzie Jetty Dive Site

Mackenzie Jetty is an interesting and unusual scuba dive site. The remains of the jetty now are just the solid wooden piles.

The jetty is about 2.5 kilometres south of the Kingfisher Bay Resort on the shores of Hervey Bay.

The GPS coordinates for McKenzie Jetty are:

-25.406885

153.012182

What’s to See at McKenzie Jetty Dive Site

There is not a great deal of interesting fish life to see at the McKenzie Jetty dive site. The main attraction is for scuba divers who like to fossick around old structures looking for interesting memorabilia. There is the possibility of turning up some old bottles, maybe some decayed pieces of machinery, and lots of pieces of old timer. According to John Wright in “Diving Southern Queensland”, in 1988 a scuba found a chamber pot dating back to the turn of the century. As this was once a popular fishing spot, there is always the possibility of getting a bunch of sinkers for making into scuba dive weights.

When To Dive at McKenzie Jetty Dive Site

The waters around the McKenzie Jetty dive site are subjected to large tidal movements. The dive site is also just across Hervey Bay from the mouth of the Mary River. This results in two main problems for scuba divers; poor visibility and strong currents. Therefore, the optimum time to go scuba diving at McKenzie Jetty dive site is just before the high tide. This means the flow will start easing and may improve the visibility.

The wind must be from the east, so that the large landmass of Fraser Island protects the McKenzie Jetty dive site from the wind. If the wind is from the west or north, the visibility plummets and it just isn’t worth getting in the water.

Details on McKenzie Jetty Dive Site

McKenzie Jetty dive site can be accessed by boat from Hervey Bay. Or it can be accessed from Fraser Island. If diving from a boat, the optimum location is about 20 metres south of the last piles poking out of the water. The jetty curved to the south and these remains are in the deepest water, of around 20 metres maximum.

Doing a shore scuba dive takes a bit more organisation, as tanks and scuba gear must be transported along Fraser Island’s rough sand tracks. However, the advantage in diving from the shore is the ease of walking off the beach into the water and following the old piles of the jetty into deeper water.

After diving at McKenzie Jetty from the shore, another unique site is to scuba dive in Fraser Island’s most famous freshwater lake: Lake McKenzie. This is a short drive from the jetty, and provides an opportunity to rinse the salt water off the scuba gear.

For scuba diving in Hervey Bay, McKenzie Jetty dive site provides a unique and interesting experience. It is different from the other scuba dive sites found in South East Queensland and may even provide a glimpse back into a time capsule of the early logging days.

Entry and Exit for Shore Scuba Diving

The entry and exit when shore scuba diving can present greater risks than breathing compressed air underwater on a scuba dive.

Checks Before Shore Scuba Diving

The shore scuba dive site must be checked before venturing into the water. Some scuba shore dive sites are regularly dived, so there should be reasonable general knowledge about the scuba shore dive site.

Boat movements should be checked before entry. It is not good to share scuba dive sites with speedboats, from a safety point of view as well as the noise and waves from the boat wash. A scuba dive safety flag should be displayed

Preferably there should be a suitable area to gear up the scuba equipment. A flat area next to the entry and exit point is best.

There must be something to see or do at the particular dive site, with an adequate scuba dive plan.

Shore Scuba Diving Entry and Exit

The entry and exit points for shore scuba dives must be considered carefully. They could be slippery or unstable that will present a risk when waddling in scuba gear on the land.

At the end of the scuba dive, the exit point might become slippery with water dripping off divers.

If the water is a bit murky and what is under the water in the first few feet can’t be seen from the bank, then it would be best to slide in feet first. A giant stride entry into murky water that hides a sharp tree stump is not good.

Second Exit Point When ShoreScuba Diving

A second exit point should be determined before getting in the water. The current should be checked for the direction of travel. Then if something goes wrong during the scuba dive, the second exit point could be used.

Scuba Surf Entry

Scuba diving through the surf can be an interesting and challenging experience.

The best time to enter the surf, say to dive on a reef or wreck outside the breakers, is when the surf is small. If the surf is large, the bottom will be stirred up making poor visibility.

Rips should be avoided. This is where the water returns to the sea. Rips are characterised by breaking waves being reduced and looking “confused” by the large amounts of water flowing against them.

Before heading out, a compass bearing should be taken on the reef or offshore dive site.

Scuba dive fins should be put on before entering the water and then the diver walks backwards into the waves. A scuba diver should get below the waves as soon as possible as it is much easier to swim below the water than on top. It is also fascinating to watch the waves breaking above the head while swimming out.

The compass should be used for direction as the sandy bottom under surf usually has nothing for reference. When at the dive site, a marker should be placed as a reference point for the start of the return swim.

Scuba Surf Exit

The procedure for the scuba surf exit is similar to that for entry in that a scuba diver should remain under the waves for as long as possible.

When safe to stand up, that is between waves, the scuba diver should walk backwards out of the water and onto the shore. Fins can be removed when out of the waves.

Shore scuba diving can be fun and also provides an opportunity for exploration. Scavenging for bits and pieces such as historic bottles or fishing sinkers to make into scuba dive weights can make shore scuba diving a rewarding dive.

Information and Practices on Shore Scuba Diving

Shore scuba diving is usually less expensive and requires less logistics than scuba diving from a boat. The main consideration for shore scuba diving is the right tide and a good scuba dive buddy. For a scuba diver intending to go shore scuba diving, there are a number of matters to consider.

Entry and exit are covered in Suite 101 article: Entry and Exit for Shore Scuba Diving.

Currents at a Shore Scuba Dive Site

Currents, or movement of water, at a shore scuba dive site can have a different impact than when diving from a boat. Entry and exit are the main issues that are impacted by current at a scuba dive site.

With a boat dive, if a scuba diver is swept away by currents at a scuba dive site, the dive boat can motor over and pick up the missing scuba diver. However, at a shore scuba dive site if a diver is swept away by currents, then the diver may need to consider an alternate exit point.

When underwater, currents at a scuba dive site can have an impact on the dive. For example, diving under surf can result in the diver moving up and down with the swells. This can be cause feelings of anxiety with some divers as there is a feeling of loss of control.

Composition of the Bottom at a Shore Scuba Dive Site

At a shore scuba dive site, the diver needs to be aware of the composition of the bottom. There could be hazards for scuba divers:

•Submerged rocks and trees that could lead to divers falling, or getting bits of equipment snagged.
•Mud can lead bad silting problems, or a scuba diver sinking into the mud.
•Rubbish such as broken bottles, bits of timber or metal can cut diver’s equipment or their skin.
Topography of the Bottom at a Shore Scuba Dive Site

A scuba diver needs to be aware of the topography of the bottom at a shore scuba dive site. For example there might just be a gentle slope from the entry point or it may be a large drop-off. Trenches, caves, sandbars, holes, cliffs can all present unknown challenges for a scuba diver.

Marine Life at a Shore Scuba Dive Site

Marine life at a shore scuba dive site can present some unique challenges. The initial consideration must be the entry and exits points, as the following can present difficulties getting in and out of the water:

•coral
•moss
•seaweed
•oysters and barnacles
•a grassy edge.
Marine stingers like box jellyfish, stinging hydra, fish with sharp spines may have to be dealt with at the entry and exit points. Under the water there can be things like large seaweed like kelp growing near the shore that can present an entanglement risk.

Some great dives can be experienced when going shore scuba diving. There are many interesting things to see and discover around the rocky headlands, river mouths, coral reefs and jetties of the ocean.

The Backward Roll Scuba Entry From a Scuba Boat Read more at Suite101: The Backward Roll Scuba Entry From a Scuba Boat

There are two main ways for a scuba diver to enter the water from a scuba dive boat:

1.The scuba giant stride entry.
2.The backward roll scuba entry.
The scuba giant stride entry is the safest and most common method of getting into the water. This is used when there is a secure platform from which to simply step off.

The scuba backward roll can be used when the scuba dive boat doesn’t have a swim deck, or ladder.

Prepare for the Backward Roll Scuba Entry

First stage of a successful backward roll scuba entry is:

•All equipment should be together.
•Know the location of the boat exit point
•Know who the dive buddy will be.
•Know what to do and where to go after entering the water. This could be to wait for the buddy; or remainder of dive group. Maybe swim for the anchor; or the trailing line out the back of the boat.
Get Into Position for the Scuba Backward Roll Entry

After getting prepared, the scuba diver must get into position for the backward roll scuba entry:

•Put on final pieces of scuba equipment.
•Sit on the side of boat with the tank supported on the side of the boat.
•All pieces of equipment should be securely fastened, or in pockets of the buoyancy compensator.
•Gauges and second stage should be sitting in the lap.
•Mask should be on, rinsed and cleaned. If possible by turning around and getting a mask full of water. If not, it should be done when in the water.
•Check all clear around – no-one standing on fins.
•Do a buddy-check – check buddy’s air is on, etc.
Get Steady for the Backward Roll Scuba Entry

Just prior to doing the backward roll scuba entry:

•Inflate the buoyancy compensator, just enough to be neutrally buoyant. But not too full so it could force against the water and smash the tank against the back of the head.
•Check any divers in the water behind have moved away. Check nothing else in the water, like a rope or dive flag. Check over both shoulders.
•Place the tank over the side of the boat, the weight being taken by the buoyancy compensator.
•Left hand holds gauges in lap, while the palm of the right hand holds the second stage eof the regulator in the mouth, with the fingers holding the mask.
Doing the Backward Roll Scuba Entry

The divemaster may count in the divers.

One last check behind; lift the legs and let the tank’s weight take the diver into the water. The tank should break the water.

The scuba diver may do a 360-degree roll, or simply drop down a few feet.

At this point the scuba diver should not panic. The buoyancy compensator should bring the diver back to the surface.

Check After Doing the Scuba Backward Roll Entry

Once back on the surface, another quick check of equipment needs to be done.

Especially important is the mask as the strap at the back of the head may have shifted from the force of the entry.

A quick signal to the divemaster on the boat that everything is OK, wait for the buddy or the rest of the dive team. Then head off for the dive.

The backward roll scuba entry is an easy way to get in the water. The main thing is not to be too concerned with the roll in the water. With the mask on and regulator in the mouth there is no problem with water getting into the nose of taking a mouthful of water.

Equipment can Affect Scuba Diver Air Consumption

Having well maintained and functioning equipment is one of the best ways to reduce air consumption when scuba diving. From leaking hoses, to inefficient regulators and problems with the buoyancy compensator, there are a myriad of ways in which equipment can lead to increased air consumption.

Streamline Scuba Equipment to Conserve Air

In the quest to conserve air when underwater on scuba, the diver’s equipment should be streamlined. Being streamlined prevents less drag in the water which has to be overcome by using more energy.

All scuba equipment should be as tight fitting and comfortable as possible.

Hose and straps should be arranged in such a way so they aren’t hanging down and causing drag, getting caught on bits of coral or rocks, or even dragging in the sand.

Bits and pieces like torches, knives, and gauges should be placed in pockets to reduce drag.

Scuba Equipment Should be Working Efficiently to Conserve Air

All equipment should be checked and serviced to ensure it is working correctly. There shouldn’t be any of those little streams of silvery bubbles rising to the surface that are a common site on most dives. These are a tell-tale sign of air being wasted.

The scuba regulator should be serviced regularly and well tuned. An efficient regulator working properly will deliver the correct amount of air. If a scuba diver needs to drag at the mouthpiece to get a lungful of air, then air is being wasted.

Hoses shouldn’t leak. The most common point for hoses to leak are at the swivel joints such as gauges or at the second stage connection. If there is a small stream of bubble from these places, then the hose needs to be replaced or repaired. This is not just to conserve air, but also for safety as a leak is a direct indication that something is wrong, and a catastrophic failure could be close.

The scuba face mask should be a tight fit that doesn’t allow water to seep in. If a scuba diver has to be continually clearing the mask of water during a dive, this simply wastes air.

Poorly fitted fins do not provide the optimum efficiency and lead to increased air consumption.

Buoyancy Compensator is a Main Source of Reduced Scuba Air Consumption

The buoyancy compensator shouldn’t leak. There are a number of places where air can escape from a buoyancy compensator, such as the dump valves; or maybe small holes in the bladder.

The buoyancy compensator power inflator should be regularly checked. It should be a good, tight fit when connected.

The oral inflator is a common place for leaks as a small piece of sand or foreign material can get caught in the mechanism and hold it open. This can create two problems when looking at air consumption. The air in the buoyancy compensator could escape, or water could get. Both these will lead to the buoyancy compensator needing to be regularly topped up during a scuba dive.

Keep Warm to Conserve Air When Scuba Diving

Heat lost from the body is energy, and part of the energy used on a dive comes from air from the scuba tank. Therefore, the warmer a diver is on a scuba dive, the less air should be used.

However, the selection of a suitable wetsuit needs to consider other issues that could lead to increased air consumption, That is, if it is too tight it will restrict movement causing the diver to work harder, which will lead to increased air consumption.

To help in the continual battle to improve air consumption while scuba diving, equipment is one area to investigate to get a few more minutes underwater.

Other areas to look at in decreasing air consumption while scuba diving are scuba techniques and the human factor.

Ways Scuba Divers Can Conserve Air Scuba Diving

For a safe, enjoyable scuba dive, a diver should work on not wasting precious air from the scuba tank.

Breathe Slow and Deeply to Conserve Scuba Air

One of the best ways for a scuba diver to conserve air scuba diving is to breathe properly on scuba equipment. It seems strange as breathing is a natural instinct, but breathing when underwater on scuba needs to be controlled.

The breathing needs to be slow, regular and deep enough to fill the lungs. This type of slow breathing allows the body to absorb enough oxygen.

Breaths should be not too deep, but just comfortable. Taking huge drafts of air from the regulator can lead to hyperventilation problems.

Short, shallow breaths are usually the symptom of an anxious diver. This type of breathing doesn’t allow enough oxygen to be absorbed into the body’s cells and can exacerbate the anxiety cycle.

Slow Down on the Scuba Dive to Conserve Air

Scuba diving is not a competition. There is nothing to gain from being the diver who covers the most amount of ground underwater. The only healthy competition between scuba divers should be who comes up with the most air in the tank after the dive. Winning this competition can be assisted by taking a slow, relaxed approach to each dive.

Use the Environment to Assist Moving Underwater to Conserve Air

The environment should be used to advantage to move around underwater. The scuba dive plan should use the current to the best advantage. That is, consider the direction of the current and address the decision which way to go first.

The current should be used to move wherever possible; rather than trying to swim against it. In some situations with a reasonably strong current flowing, it may be possible for a diver with good buoyancy skills to hang upright in the water and let the current take them along for the ride.

In some dive sites, such as close in to a small island, the ocean swells may impact on the diver underwater. In this situation, the scuba diver should use the swells by only swimming when the waves are in the right direction; stop when the wave recedes and then swim forward again on the next swell.

To Conserve Air, Get Scuba Dive Fit out of the Water

There are many advantages in getting scuba dive fit out of the water.

It would be expected that a fit and healthy diver is more efficient than an unhealthy diver. And therefore would use less oxygen. Even if this assumption wasn’t true, there are the many other well know reasons for getting, and keeping, fit and healthy.

When out of the water, scuba divers should concentrate on techniques to improve breathing. Yoga, relaxing breathing techniques, and focussing on stress reduction out of the water can all improve a scuba diver’s air consumption. Anything to make a relaxed, easy breathing diver.

Aerobic exercise when not scuba diving that works the heart and lungs will build strength in these areas that will improve air conservation while underwater.

Possibly the best way to address the human elements of improving air consumption is by simply diving regularly. Regular scuba diving will build “dive fitness” with accompanying decrease in air consumption.

Other areas to look at in decreasing air consumption while scuba diving are scuba diving techniques and equipment issues.

Different Types of Recreational Scuba Diving

The following is a brief summary of just some of the areas in which a recreational scuba diver can explore the underwater world.

Coral Reef Scuba Diving

One of the most enjoyable aspects of scuba diving can be a relaxing scuba dive over a coral reef. If the conditions are right, a scuba diver can see a magnificent vista all around.

Fish life coming and exploring the scuba diver, majestic fish like manta rays, huge wrasse and groper. Turtles, non-threatening sharks and tiny fish like the famous Nemo clown fish can all be seen on a coral reef dive.

Coral reef scuba diving is usually safe in that most of the marine life and colour is experienced in just thirty feet of depth. Shore scuba diving off places like Lady Elliot Island on Australia’s Great Barrier Reef is a great place to experience the unique aspects of coral reef scuba diving.

Exploring Sunken Wrecks Scuba Diving

Exploring sunken wrecks can be an exciting and challenging underwater activity.

In the South Pacific there are a large number of sunken wrecks from World War Two. One of the most famous is the wreck of the President Coolidge, a sunken ocean liner in the harbour at Santo in Vanuatu.

Wreck diving has risks in that a recreational scuba diver is swimming inside a sunken vessel. It can be dark, cramped and it is possible to get lost inside. So precautions like a divemaster guide and safety lines may be needed.

Another problem with scuba diving on wrecks is that many are usually in deep water requiring decompression to ensure divers don’t get the Bends. However, this type of recreational scuba diving can provide a huge adrenalin hit when a diver surfaces after exploring within the bowels of a sunken ship.

Scuba Dive Travel Trips

Scuba diving can open up the world by providing a focus on a holiday. Organising the trip, packing the scuba equipment, then heading off to some exotic location in a far part of the world to get wet underwater makes for a great holiday.

For example, a recreational scuba dive trip can combine the above relaxing coral reef diving and challenging wreck diving. This type of scuba holiday can be had at some remote locations like Truk Lagoon in Micronesia.

It is reputed that some of the best coral reef scuba diving in the world is in places like the Maldives in the Indian Ocean, the Red Sea off Egypt and on Australia's Great Barrier Reef.

Cave Scuba Diving

Like wreck diving, cave scuba diving can be an exciting and challenging underwater activity for a recreational scuba diving. Slipping into the dark waters of a cave can be a solid adrenalin hit.

And as with wreck diving, there are a range of dives that a recreational scuba diver can undertake. From deep, dark diving (after an intensive training course) in Australia’s Cocklebiddy Caves on the desert of the Nullabor Plain; to an easy dive in the Grotto de la Troisieme, a freshwater cave in New Caledonia.

Just Being Underwater

For every type of diving a recreational scuba diver wants to undertake; there are a number of scuba divers who simply enjoy the thrill of breathing underwater. That is, being at one with the fish and underwater landscape.

Whether cave diving, exploring wrecks or simply getting wet at a local scuba dive site, it is a unique experience to strap on a scuba tank and drop into the fascinating “inner space” of the underwater world.

Tangalooma Wrecks Scuba Dive Site

Some novice divers get the Tangalooma Wrecks confused with the Curtin Artificial Reef.

These are two separate artificial reefs on the western side of Moreton Island. The Tangalooma Wrecks are just north of the Tangalooma Island Resort and can be seen above the waterline. While the Curtin Artificial Reef can not be seen above the water and is about seven kilometres to the north.

History of the Tangalooma Wrecks Artificial Reef

The Tangalooma Wrecks Artificial Reef was started in 1963 when a group of recreational boat owners lobbied the government for an artificial harbour to be built on the western side of Moreton Island.

The result was around 15 de-commissioned steam driven dredges and barges sunk on a sandbank about 500 metres off the beach.

Location of the Tangalooma Wrecks Artificial Reef

The Tangalooma Wrecks are only a short walk along the beach north of the Tangalooma Island Resort. This resort was once the site of the Tangalooma Whaling Station.

The reef is easy to see, with the twisted mass of metal, old dredges and funnels poking out of the water.

The GPS coordinates for the Tangalooma Wrecks Reef are:

-27.163202 153.368669

What’s at the Tangalooma Wrecks Artificial Reef Scuba Dive Site

The Tangalooma Wrecks Artificial Reef scuba dive site is a shallow scuba dive, with a maximum depth of only 10 metres. This makes it a good location for introductory scuba dives. Many scuba instructors use this site as an introduction to open water scuba diving for students working towards their open water diving certification.

There are some penetration dives on the wrecks. These should only be attempted with a scuba divemaster or scuba instructor who is well acquainted with the wrecks.

Fish Life at the Tangalooma Wrecks Artificial Reef

Apart from the excitement of scuba diving on sunken wrecks, the Tangalooma Wrecks offers a prolific display of marine life.

Before the artificial reef was formed, the area was basically a marine desert. A flat, sandy bottom didn’t provide much in the way of marine habitats. However, now with the abundance of nooks and crannies, and a place for soft corals and seaweeds to grow, the reef teems with life.

There are a myriad of tropical fish, placid wobbegong sharks, schools of trevally, with soft corals over the sunken bits of the wrecks.

Scuba Dive Plan for the Tangalooma Wrecks

Best time to scuba dive the Tangalooma Wrecks is either side of the high tide, so that the change of tide is in the middle of the dive. Divers need to carefully plan around the tides as the currents can be quite strong.

A good scuba dive plan for the Tangalooma Wrecks is a drift dive. However, this must be carefully planned so the currents are not too strong. The boat needs to be well coordinated, especially with the pick-up at the end of the dive.

Snorkelling at the Tangalooma Wrecks

With the Tangalooma Wrecks being in such shallow water makes it a great place for snorkelling.

There are a few things to be aware of when snorkelling at the Tangalooma Wrecks.

Stingers, like fire coral or stinging hydra, can give a snorkeller a painful rash. Stonefish with their poisonousness barbs can be a threat if accidentally stood on.

Sharing the Tangalooma Wrecks Dive Site With Fishermen

With the reef attracting so much fishlife, the reef is a magnet for fishermen. And therefore scuba divers and snorkellers must share the site.

The main risk when underwater is the possibility of getting tangled in some old fishing lines that hang around the wrecks. A dive knife should be carried when diving or snorkelling at the Tangalooma Wrecks.

As the Tangalooma Wrecks form a harbour, there is a large number of boat movements in the area. A scuba diver or snorkeller needs to be extra vigilant; especially after a drift dive.

The Tangalooma Wrecks Dive Site is a fascinating spot for a scuba dive or for snorkelling. Sunken wrecks, prolific marine life in a shallow, easily accessible location make it a dive site that offers a lot for a scuba diver or snorkeller.

Curtin Artificial Reef Scuba Dive Site, Brisbane

Curtin Artificial Reef off the east coast of Australia comprises about 20 wrecks, all offering an interesting scuba dive. There are couple of whale chasers left over from the Tangalooma Whaling Station, a number of barges and even an old Brisbane tram.

History of the Curtin Artificial Reef

The Curtin Artificial Reef started in 1968 when the Underwater Research Group of Queensland (URGQ) obtained approval to form an artificial reef in Moreton Bay. The first item to be placed on the reef was a gravel barge.

Frank Curtin, a member of the Underwater Research Group of Queensland, was the main driver behind the formation of the artificial reef and so the reef was named in his honour.

Location of the Curtin Artificial Reef

The Curtin Artificial Reef is about seven kilometres north of the Tangalooma Island Resort; between the settlement of Bulwer and Cowan Cowan Point. The wrecks sit on the sandy bottom, though a number have been covered in the mud and sand that flows on the currents through the scuba dive site.

The Curtin Artificial Reef should not be confused with the Tangalooma Wrecks, that is an artificial breakwater about seven kilometres to the south.

The GPS coordinates for Curtin Artificial Reef are:

-27.11005 153.3625

When to Dive at Curtin Artificial Reef Scuba Dive Site

The best time to dive the Curtin Artificial Reef is either side of the high tide, so that the change of tide is in the middle of the dive. Divers need to carefully plan around the tides as the currents can be quite strong.

The URGQ recommends the optimum time to dive the Curtin Artificial Reef is when the high tide (recorded at the “Brisbane Bar”) is between 9.00 am and 11.00 am. This allows enough time either side of the high tide to get the best conditions.

On incoming tide the current runs north to south.

On the ebbing tide, the current runs south to north.

A drift dive can be a good dive plan, but must be carefully planned so the currents are not too strong. The boat needs to be well coordinated, especially with the pick-up at the end of the dive.

Scuba Dive Plan for the Curtin Artificial Reef Scuba Dive Site

There are some penetration dives possible; especially on the larger wrecks like the tug Melbourne that was sunk on the reef in 1979.

However, as with any penetration scuba diving on sunken wrecks, extreme care and rigorous dive planning is needed. A scuba divemaster with detailed knowledge of the wrecks should accompany any scuba diver wanting to do a penetration dive into the wrecks.

The Underwater Research Group of Queensland “recommends that none of the wrecks are penetrated.”

The tide and associated currents are a large factor in a scuba dive plan for the Curtin Artificial Reef. If a scuba diver does plan to penetrate into one of the wrecks the dive should be planned so it is done at the change of tide.

If possible, it can be a good idea to carry an underwater map of the Curtin Artificial Reef scuba dive site. A map is available from the URGQ website.

Fish Life at the Curtin Artificial Reef

Apart from the excitement of scuba diving on sunken wrecks, the Curtin Artificial Reef dive site offers a prolific display of marine life.

Before the artificial reef was formed, the area was basically a marine desert. A flat, sandy bottom didn’t provide much in the way of marine habitats. However, now with the abundance of nooks and crannies, and a place for soft corals and seaweeds to grow, the reef teems with life.

There are batfish, a myriad of tropical fish, gropers, placid wobbegong sharks, schools of trevally, various types of wrasse and the occasional rays.

Sharing the Curtin Artificial Reef Dive Site With Fishermen

With the reef attracting so much fishlife, the reef is a magnet for fishermen. And therefore scuba divers must share the site.

The main risk when underwater is the possibility of getting tangled up in some old fishing lines that hang around the wrecks. A dive knife should be carried when scuba diving the Curtin Artificial Reef.

There is also the risk of boats cruising around above, so a scuba diver needs to be extra vigilant on the ascent; especially after a drift dive.

And when underwater, a scuba diver needs to be wary of boats anchoring above. It’s not a good thing to be hit on the head by a wayward anchor while underwater at 20 metres.

The Curtin Artificial Reef Dive Site is a fascinating scuba dive. Sunken wrecks, prolific marine life, and challenges with currents make it a dive site that offers a lot for a scuba diver in the one dive.

Snorkeling, Exploring Another World

There is historic evidence that as far back as 3000 B.C., sponge divers practiced a form of snorkeling by using hollow reeds to help them breath when underwater.

Snorkeling is an inexpensive hobby requiring only a good quality eye mask, a snorkeling tube and swim fins to help navigate more quickly through the water.

Buying A Snorkeling Mask

The mask is one of the most important pieces of snorkeling equipment. It should fit snugly and comfortably on the face without leakage. It’s worthwhile to spend a little more money by going to a scuba or diving equipment store and having the mask professionally fitted.

The Snorkel, A Diver’s Breathing Tube

The snorkel provides the lifeline that allows divers to float face down in the water for extended periods of time. It consists of a flexible tube, usually made of plastic or rubber. The length of the snorkel tube varies between 12 and 18 inches. The length and bore, or diameter, of the tube depends on the size of the snorkeler. Larger people require more air and a longer tube with a wider bore will allow more air in and out of the tube.

The mouthpiece of the snorkel consists of two parts, a large, oval lip flange which fits inside the divers lips and the bite piece which is gripped between the teeth. The bite piece is to hold the snorkel in the mouth and should not be bitten too hard. The divers lips covering the flange provide the seal for the mouthpiece.

The top end of the snorkel should have some features to prevent water from coming in when waves splash over the top. Two of the most common are a simple ping-pong ball held in a tiny cage or diagonal plates, which allow water to flow in and out.

Finally, the snorkel should have an adjustable clip, about half way down the straight part of the tube, to attach the mask strap. The clip will hold the snorkel upright in the water and free up the diver’s hands for swimming.

Swim fins are an optional piece of snorkeling equipment, however, they do help to propel and manoeuvre the diver through the water more quickly. This is important when snorkeling in the Carribean and following that one elusive, multi-coloured fish dodging in and out of the coral reef. Most fins are adjustable, but make sure they are the right fit, not too loose or too tight.

Using the Snorkeling Equipment

For first time snorkelers, it’s a good idea to become comfortable wearing the mask and snorkel tube. Start in calm, shallow water by relaxing and breathing normally through the tube. Concentrate on watching the fish and viewing objects on the sea floor.

If the mask fogs up, use a little spit or mask defogger to clear the moisture and swish it around in the water before putting the mask back on.

Snorkeling can be a relaxing and exciting hobby, but some caution is advised:

•Do not snorkel, if you can’t swim
•Never snorkel alone, always have a swimming companion
•Stay away from areas with high boat, Jet Ski, surfing or water skiing traffic
•Raise a hand up out of the water before surfacing to make sure the area above is clear
•Do not step on or otherwise damage delicate coral reefs or underwater marine life
•Coral reefs have razor sharp edges, do not get to close
•If light-headedness or breathlessness occurs surface immediately and head for shore
•Wear a tee shirt or use a sun block with a high SPF on exposed areas of the body.
Snorkeling is an inexpensive and fun way to experience the incredible diversity of the undersea world. Floating freely above and among schools of brightly colored marine life can lift the soul and calm the mind.

Problems of Nitrogen Narcosis in Scuba Diving

The common term for nitrogen narcosis used in the scuba diving fraternity is the “raptures of the deep”. Another common term is a scuba diver suffering this condition is said to be “narked”.

What is Nitrogen Narcosis?

Nitrogen narcosis is a condition in scuba diving where a scuba diver has feelings of elation and euphoria. It is similar to being slightly intoxicated with alcohol, or from having nitrous oxide when undergoing certain medical procedures such as dental work.

Because of this impact of a scuba diver feeling invincible and reduced anxiety underwater, the condition has the potential to be extremely dangerous. Some divers have been known to take their regulator from their mouth; while other have lost all awareness of depth and simply continued swimming down to greater depths and into greater trouble.

Nitrogen narcosis usually occurs at depths greater than 30 metres. However, the condition can affect some scuba divers at a lesser depth.

The symptoms reduce as the diver ascends to shallower depths.

What Causes Nitrogen Narcosis?

Nitrogen narcosis is caused by the impact of nitrogen in the body.

A scuba diver breathes a normal mix of air from a scuba tank. This air contains around 79% nitrogen.

When breathed at depth the partial pressure of the nitrogen results in more nitrogen in the body. However, as nitrogen is an inert gas it doesn’t react with the body’s blood and tissues.

Because the nitrogen doesn’t react chemically with the body, it is considered that the nitrogen affects the signals that are sent along the nerve fibres in the body. This results in the impact being mainly related to brain and nerve functions.

Signs and Symptoms of Nitrogen Narcosis

Nitrogen narcosis affects scuba divers in different ways. The following are some of the reported signs and symptoms impacting the cognitive function of a scuba diver with nitrogen narcosis:

•General feelings of euphoria
•Feelings of elation
•A sense of well-being
•Over confidence
•Laughter
•Light-headedness
•Loss of decision making ability
•Memory problems.
Physical symptoms of a scuba diver with nitrogen narcosis can be:

•Vertigo
•Tunnel vision
•Impaired coordination and concentration
•Tingling or numbness in the body’s extremities.
The biggest problem with these symptoms is that a scuba diver suffering from some of the above symptoms of nitrogen narcosis may not be able to recognise that they have the symptom.

For example, a scuba diver suffering with a sensation of over-confidence and euphoria may not be able to think that there is something wrong because these are “good” type sensations. The loss of decision-making ability is obviously a serious problem if a scuba diver has to calculate decompression times underwater.

Problems can so easily occur when a scuba diver has these feelings of extreme confidence. They can go off and do things underwater that they wouldn’t normally do.

Scuba Diving’s Martini Law and Nitrogen Narcosis

In the diving fraternity, the impact of nitrogen narcosis in relation to depth is known as “Martini’s Law”. This is roughly based on the analogy that for each 10 metres in depth, the effect is like consuming one martini. At 30 metres, a scuba diver may feel like they have drunk three martinis.

This is a very rough guide only and should not be relied on to predict the onset of nitrogen narcosis

How Scuba Divers Can Prevent Nitrogen Narcosis

The onset of nitrogen narcosis is directly related to depth. The deeper the scuba diver goes, the greater the impact of nitrogen narcosis.

It is almost impossible to predict the depth that symptoms may start showing as nitrogen narcosis impacts each scuba diver differently. And the impact can vary from each scuba dive.

There are many variable such as cold, stress, fatigue. It is even thought that nitrogen narcosis may be worse depending on the amount of alcohol or some drugs that may have been taken into the body a few days earlier.

The best way to prevent nitrogen narcosis is to be aware of the possibility of narcosis occurring, and then if it does the scuba diver should immediately ascend to a shallower depth.

Scuba diving buddies should always be on the lookout for signs of nitrogen narcosis; especially on a deep dive over 25 metres.

The problem of nitrogen narcosis can best be addressed by the following:

•using a good scuba dive plan
•implementing good scuba diving practices
•keeping mentally and physically healthy
•a good relationship and understanding between scuba dive buddies
•keeping in shallow depths.
Nitrogen narcosis should not be something that is treated lightly, or considered a scuba diving myth. “Raptures of the Deep” is a true physiological problem that has the potential to be fatal for scuba divers.

Ear Injuries and Damage Caused by Scuba Diving

Damage to a scuba diver’s ears can be anything from an annoying case of swimmer’s ear or can be so significant the injury could result in permanent hearing loss.

Scuba Diving and Middle Ear Barotrauma

Trauma to the middle ear is one of the most common scuba diving injuries. It is called Barotitis Media and is usually caused by a middle ear squeeze.

If pressure in the middle ear is not equalised on descent, the body tries to equalise the inner ear by forcing fluid and blood into the middle ear cavity. This fluid is an attempt by the body to fill the inner ear cavity to reduce the pressure.

Middle ear barotrauma feels like a fullness in the ear. Hearing may be muffled, or there may even be complete hearing loss in the ear.

A scuba diver who believes they may have suffered middle ear barotrauma (Barotitis Media) during a scuba should seek treatment from a doctor.

Rupture of the Ear Drum During Scuba Diving

The ear drum is the thin membrane between the out ear canal and the middle ear. Its medical term is the tympanic membrane.

The ear drum prevents water and other foreign objects from getting into the middle ear.

The eardrum can rupture due to a scuba diver not equalising the ears on the descent. The difference in pressure across the eardrum on descent forces it to bulge inwards until eventually it will rupture. This lets water into the middle ear.

Symptoms of a ruptured eardrum while scuba diving are:

•A reduction in hearing;
•A ringing sound in the ear;
•After the ascent, there may be a bloody discharge from the ear.
Inner Ear Barotrauma While Scuba Diving

An inner ear barotrauma occurs when a scuba diver over equalises their ears on descent. Excessive Valsalva technique puts excessive force on the tiny membrane between the middle ear and the inner ear. These are called the round and oval windows.

Symptoms are vertigo, nausea, loss of hearing or a ringing sound in the ear.

This is the most serious ear injury to occur during scuba diving and can lead to permanent hearing loss in the ear. Medical attention should be obtained as soon as possible if a scuba diver suspects they may have suffered an inner ear barotrauma.

Swimmer’s Ear and Scuba Diving

Swimmer’s ear, or Otitis Externa, is an infection of the outer ear and ear canal. It is usually associated with the ears being wet and bacteria growing in the dark, damp ear canal.

For more information on Swimmer’s ear, refer to Suite101 Article: Causes and Prevention of Swimmer’s Ear.

Preventing Ear Injuries While Scuba Diving

A scuba diver should be aware of the high risk of injury to the ears from scuba diving. The main ways in which a scuba diver can prevent ear injuries while scuba diving are:

•don’t do a forceful Valsalva technique to clear the ears;
•if having trouble equalising on the descent, rise a few metres;
•avoid diving with a cold or any illness that results in the ear being congested;
If a scuba diver can’t equalise their ears, then they shouldn't scuba dive.

Damage to the ears from scuba diving can result in permanent hearing loss. Therefore it is wise for scuba divers to care for their ears and be well aware of the risks to the ears from the impact of pressure during scuba diving.

Using a Rigid Inflatable Boat for Scuba Diving

An inflatable boat for scuba diving conjures thoughts of a dinky toy that can’t take the punishment of a rough scuba dive trip. However, inflatable boats make an excellent scuba dive boat.

What is a Rigid Inflatable Boat?

These boats are not a true inflatable boat. Two large buoyancy collars are attached to a rigid aluminium hull. Hence the name: Rigid Inflatable Boat, or RIB.

The buoyancy collars are actually two tubes. The outer casing attaches to the aluminium hull by a track system with the inner tube, like a bicycle tube, fitting inside. The rigid hull forms a normal planing vee and the buoyancy collars attach on the side of this.

The inner tube should last about ten years, though the outer tube has to be replaced every three to five years depending on use.

This double tube arrangement has a few advantages. If a leak in the inner tube occurs it is a simple matter of removing the entire tube to repair it. A hole in the outer casing can be repaired from inside making the repair less noticeable. When the outer tube requires replacing it is almost like a new boat.

With the separate inner tube there is no chance of air escaping by wicking through the fabric.

The air pressure needs adjustment due to the seasonal changes in temperature.

How Good is a Rigid Inflatable Boat on the Water?

A RIB is a surprisingly solid boat. It has a feel that it can take any punishment that scuba divers can throw at it. The buoyancy collars are made of extremely tough vinyl that is forgiving but has the strength needed in such a boat.

Out in the open sea the characteristic of these boats becomes apparent. A RIB is an extremely dry boat. Many owners say their boat is “dry” but experienced divers would have spent long hours in scuba dive boats of similar size and have always copped spray on the trip to the scuba dive site.

But the RIB is different. It is possible to sit on the buoyancy collars and still not get spray in the face, though the safest place when under full power is on the deck.

The buoyancy collars not only give the boat its stability and flotation they also direct the spray away from the boat. This phenomenon is even more noticeable when punching into a messy sea of wind-blown chop on top of large swells. This can be useful if a scuba diver is prone to seasickness.

How Good is a Rigid Inflatable Boat for Scuba Diving?

At the scuba dive site the boat's stability comes to the fore. In swells and slight chop the buoyancy collars do their job again and smooth out the ride, even with divers moving around the boat. This makes gearing up a breeze, though organisation is needed as is usual on any scuba dive boat of this size.

Entering the water is the backward roll over the side: a simple manoeuvre on the buoyancy collars.

Getting back on board is another matter. The best way is to porpoise over the pontoons. It's simply a matter of removing the weightbelt followed by buoyancy compensator and tank, then kicking hard with fins and pulling up on the buoyancy collar’s safety ropes. The wetsuit slips over the wet vinyl of the buoyancy collars allowing the scuba diver to slide into the boat.

Using a Rigid Inflatable Boat for Scuba Diving

The Rigid Inflatable Boat is perfect as a scuba dive boat. It is stable, dry and has heaps of room. With some careful organisation, a 4.8 metre RIB with a 70 horsepower motor could take up to six divers.

This sized RIB would be suited for a quick trip out to the dive site, have the dive then back in. Two dives would be possible but the cramped conditions and wouldn't make for a comfortable time between dives.

A Rigid Inflatable Boat would have many uses in the dive industry. For research divers, dive club boats, dive trip operators who want a boat to take four to six divers out for a quick one tank dive. In fact they are suitable for any dive operation where a robust, stable dive platform is required.

The Most Beautiful Dive Sites in Costa Rica

Brilliantly colored corals, lazy sharks and giant turtles are just a few of the wonders to be experienced in the waters off of Costa Rica. However, this small country has a lot of coastline so it helps to know where the best dive sites in Costa Rica are before hopping in the water. Flanked by the Caribbean to the East and the Pacific Ocean to the West there are plenty of options for a Scuba diver to explore. Consider these dive sites when planning a Costa Rica diving vacation.

Experience the Best Dive Sites of Caño Island

Perhaps one of the most talked about dive sites in Costa Rica is Caño Island just 12 miles west of Drake Bay on the country’s Southwest coast. In the heart of a biological reserve the main attraction around this island are the large pelagic species swimming about. These include white tip reef sharks, bull sharks, over five species of dolphin, various rays, and turtles according to the dive operators Costa Rica Adventure Divers. Corals are also common although less abundant than in the Caribbean.

The island is surrounded by six dive sites with interesting rock formations creating stone pinnacles rising from the sea bed. The average dive depth is about 15-20 meters. The best dives occur from February to June.

Take a Scuba Diving Vacation to Gunacaste

Guanacaste province on the Northwest coast of Costa Rica is a launching pad to a few of Costa Rica’s best diving sites – the Catalina Islands and the Bat Islands. The town of Tamarindo on the mainland is only about 25 minutes from the Catalina Islands, an archipelago of about 20 rocks. The islands are well known for its sharks, sea turtles, and large schools of manta rays. The currents here can sometimes be strong, so the dives are generally recommended for more advanced divers. According to the tour operators Tierra Verde the best time to see schools of mantas are from December through May.

Meanwhile, the best time to dive the Bat Islands or Islas Murcielagos, is from March through November. Look for large bull sharks and eagle rays as well as plenty of corals. Caverns and bridges dot these dive sites which are slightly north of the Catalina Islands.

The Best Costa Rica Dive Sites in the Caribbean

Most Scuba divers spend the bulk of their Costa Rica dive time in the Pacific, however the reefs of the Caribbean should not be ignored. On the Southeast coast lies Cahuita National Park, just south of Cahuita town and about 43 kilometers south of Limón according to the Costa Rica Tourism and Travel Bureau website. The dive sites within the park are rich in coral gardens surrounded by multitudes of tropical reef fish. Look for brain corals, sea fans, angelfish, barracudas, and stingrays. Also look for the cannons on the sunken 18th century slave ship north of the river Perezoso.

Scuba Diving on a Christmas Caribbean Vacation

This Christmas, trade in cold sludgy sidewalks for white sand beaches with a visit to the Caribbean. The weather is beautiful with temperatures ranging between 75°F to 85°F and with the hurricane season over diving is looking good again. A Christmas Caribbean vacation is not complete with out learning about the area’s fascinating marine life. So grab a wetsuit and check out the Caribbean’s best dive sites.

Listen to Whales on a Scuba Vacation in the Turks & Caicos

The Turks & Caicos Islands are a great place to be for a Christmas Caribbean vacation as rainy season is over and whale season is just beginning. According to the Caribbean dive operators Bay Adventures website, humpback whales can be heard throughout the islands from December through April. The Columbus Passage separating South Caicos from Grand Turk is a major highway for migrating manta rays in the summer, humpback whales in the winter, and turtles year-round. Dive sites around the island are also home to coral gardens, colorful sponges, and schooling fish.

Take a Scuba Vacation to Cozumel, Mexico

December is a busy time for Cozumel and it’s no wonder so many people want to take their Caribbean Christmas vacation to Mexico. Cozumel Reefs National Marine Park is a place of great biodiversity and the government has gone to great lengths to protect it. Divers are required to pay a $2 entry fee per day and all funds go to reef conservation according to the tour operators Aqua Safari. The dive guides at Carayitos Advanced Divers do an excellent job of describing the various dive sites around Cozumel. Expect to see rays, sea turtles, nurse sharks, and large sea fans. Many of the dives around Cozumel are drift dives due to strong currents.

Find the Best Belize Diving on a Christmas Caribbean Vacation

Sunny skies are key to a successful dive vacation and December falls right inside of Belize’s dry season. Expect great visibility and calm seas while diving out of San Pedro on Ambergris Caye. According to the dive operators at Scuba-Belize.com there are over 40 named dive sites dotting the 20 miles of barrier reef running parallel to Ambergris.

Part of the second largest reef system in the world, the turquoise blue waters of Belize dive sites boast nurse sharks, stingrays, and schools of barracuda. Colorful corals are home to large schools of fish and lobsters. Belize is a popular destination for a Christmas Caribbean vacation, just watch out as there will be plenty of other tourists heading there too.

Avoid Caribbean Christmas Crowds on Saba

This undiscovered treasure is known as the “Unspoiled Queen” according to the tour operators, Cardonna Dive Adventures. Receiving only 25,000 visitors a year, this small island’s untouched dive sites make an excellent escape from Christmas crowds. Saba is the smallest island of the Antilles and offers scuba diving year round with water temperatures dropping to about 77°F to 80°F in the winter. Marine life includes tropical fish, groupers, reef sharks, and bull sharks. The dive sites are also well known for underwater mountains and pinnacles rising majestically from the seafloor towards the surface.

Scuba Diving at Mudjimba Island Scuba Dive Site

Mudjimba Island is a tiny island on Queensland's Sunshine Coast; a little over an hour’s drive north of Brisbane.

History of Mudjimba Island Scuba Dive Site

There are two Aboriginal dreamtime stories about Mudjimba Island.

The name Mudjimba refers to an Aboriginal legend in which a woman became stranded on the island, where she lived into old age.

The other story is about the creation of Mudjimba Island. There were two men: Coolum and Ninderry, who fought over a woman called Maroochy. Ninderry knocked Coolum’s head off and it landed in the sea to become Mudjimba Island.

Modern history tells of Mudjimba Island once being owned by actor Sean Connery. He was married to Australian actress Diane Cilento in the 1960s and early 1970s. They were said to have spent time on Mudjimba Island during their marriage.

Location of Mudjimba Island Scuba Dive Site

Mudjimba Island is about one kilometre offshore from Mudjimba Beach on Queensland’s Sunshine Coast. It is about three kilometres north of the outlet of the Maroochy River. This results in mediocre visibility. Fifteen metres on a good day, but average around seven metres.

The GPS coordinates for Mudjimba Island scuba dive site are:

-26.614611, 153.114674

What’s at Mudjimba Island Scuba Dive Site

The soft corals at Mudjimba scuba dive site provide an amazing array of colour. In a short scuba dive a diver may see many different colours of bright fluorescent soft corals.

This feature alone would make Mudjimba Island scuba dive site a perfect spot for macro underwater photography buffs.

Fish Life at Mudjimba Island Scuba Dive Site

A sad feature that can be found at many similar sites around Australia is the lack of large fish. Most have been taken on the fishing line over many years of fishing at the spot.

The occasional meal-sized bream warily swims through at Mudjimba Island, but the majority of the fish left are small tropical fish.

Scuba Dive Plan for Mudjimba Island Scuba Dive Site

Being an island, Mudjimba Island has to be a scuba boat dive. The island offers a safe comfortable dive in any prevailing winds, though anything over 15 knots can make the trip across from the Mooloolaba River boat harbour a bit uncomfortable.

Good scuba dive sites can be found all around the island, all in a maximum of 12 metres, which makes for long easy dives.

The corals are predominantly soft with many outcrops, bommies and gullies making an interesting seascape.

Snorkelling at Mudjimba Island Scuba Dive Site

Mudjimba Island is a good location for snorkelling. The coral gardens with a range of soft corals and rocky ledges start around two metres.

Mudjimba Island scuba dive site is a reasonable dive site. The poor visibility and lack of large fish life are a negative. A positive for this scuba dive site is the range of soft corals.

Mudjimba Island is a good second scuba dive site, after visiting other sites in the Sunshine Coast area.

Snorkeling the Cenotes in the Mayan Riviera

The Mayan Riviera has very few above ground sources of water and these cenotes join up to underground rivers that lead into the ocean.

Getting to Cancun

Upon entering the Cancun airport things are relatively easy to navigate. Customs lines are long but go quickly. Luggage is then picked up and everyone heads to immigration, which can take a bit of time as each piece of luggage is scanned upon exiting. After that there are lots of taxi people that are hanging around, so it’s a good idea for travelers to have made reservations and know where they are going before exiting.

Renting a Car in Cancun

Don’t be afraid to rent a car here. It’s easy to get around and hard to get lost as there is only one main road. Beware of insurance additions at the rental car agencies. Rental costs can easily be doubled with the addition of taxes and the insurances that are required. Also be aware of girls in the rental car area trying to sell timeshares.

Where to stay in Cancun or Playa Del Carmen?

Either is fine. Playa del Carmen is actually closer to the Cenotes. A recommendation is the Barcelo Maya Palace All Inclusive resort. It's massive, has great food and great accommodations.

Hidden Worlds

The best cenote snorkeling is at Hidden Worlds. In addition to snorkeling, they also offer zip lining and rappelling. Different package options are offered. For cenote snorkeling, The Church Cenote and Tak be Hal Cenote are both very large caverns. A guide is provided and will point out items of interest. To get back to the cenotes, travel is by “Mexican Limo” which is a 15 minute tractor/bus through the jungle. The first cenote, the Church, has some pretty steep stairs that visitors actually have to climb down backwards. The water in the cenote is very cold, 72 degrees, so be sure to rent a wet suit. There aren’t many fish in the cenotes but there are lots of stalactites and stalagmites.

Paths through the jungle will lead to the next cenote, Tak Be Hal, but don’t worry there is still a guide to get everyone there. Bring bug spray as there are tons of mosquitoes. Make sure to reapply it when getting out of the water. This cenote is even a larger cavern than The Church and patrons can actually repel or zip line into it.

Snorkeling in fresh water is definitely a different experience than snorkeling in salt water and is highly recommended.

Scuba Diving Trips to Gran Canaria

Scuba diving trips to the island of Gran Canaria are becoming increasingly popular. The island is something of an unappreciated gem for divers and is rapidly gaining recognition as one of Europe’s great scuba diving locations.

Why Gran Canaria is a Great Scuba Diving Location

The island rests amid a confluence of different seas and oceans, making it something of a unique scuba diving environment. Marine species from the Mediterranean, Atlantic, Red Sea and Africa can be found in Canarian waters. The island is host to some of the most beautiful marine life on earth.

Manta Rays are regularly seen from October onwards, especially in the North of the island, around the Caleta region. Divers have reported seeing schools of the huge animals during the winter months. Other species include sizeable barracuda, angel sharks, trumpet fish, monumental schools of Roncadores, cuttle fish, moray eels, snapper, octopus and a variety of stingrays.

The El Cabron Marine Reserve in Arinaga

In 2004 UNESCO approved Gran Canaria as a World Biosphere Reserve and nowhere represents the beauty and diversity of the island’s marine environment better than EL Cabron.

One of only three marine reserves in the Canary Islands, El Cabron is a Mecca for divers of all abilities. This protected reserve (into which boats cannot travel) is home to a wide array of sites, allowing divers to explore a plethora of submerged volcanic mounts, walls, canyons and swim throughs.

Stingrays, angel sharks and immense schools of barracuda patrol this underwater paradise; while moray eels, octopus and even sea horses make their homes in the rocks, nook and crevices of the volcanic strata. Visibility in the reserve is generally excellent, rarely falling below 20 metres. No scuba diving holiday to the island would be complete without a trip to Arinaga.

Wreck Diving

While most of the popular diving is to be found along the southern reaches of the island (incidentally where the major holiday resorts are to be found) there are some excellent wrecks worth exploring in the northern part of the island, off the coast of the capital Las Palmas.

Two of the largest wrecks in the Canaries (the Arona and the Kalais) are to be found a short boat ride out of the port of Las Palmas. These dives, ranging as they do from between 27-35 metres are for the more experienced only, as conditions can be somewhat mercurial in the North, with strong currents commonplace.

The Mogan wrecks, just outside the popular tourist village in the South, are an extremely popular diving destination for the slightly less experienced or adventurous diver. They are two small wrecks sunk to provide an attraction for the daily Yellow Submarine trip. Most dive schools time their entries to match the hourly voyage of the submarine and the trip is a bizarre and unique addition to any diving holiday on the island.

Gran Canaria is a Year Round Scuba Diving Location

The island has one of the world’s best climates, with temperatures still approaching the thirties throughout the winter months. In terms of water temperature it is not uncommon to see surface temperatures of 21 or 22 degrees Celsius in December. The water rarely drops below 18 degrees, even in the coldest of the winter months. The average temperature hovers around 23 degrees Celsius.

In addition to being a year round diving destination, holidaymakers are able to dive on every side of the island, rather than simply the over-fished and busy tourist areas, which is the norm throughout the Mediterranean.

An Island of Contrasts

The island itself is easily accessible from all parts of the European mainland and North America, which adds to its attractiveness as a holiday destination. Holiday accommodation exists to suit every taste and budget. The island offers travellers a welter of contrasts, from the bustle and excitement of the thriving southern resorts to the peace and solitude of the mountainous centre of the island.

Non-divers or those taking a rest from the undersea world will find much to do throughout the year. The island is ferociously Spanish in terms of its cultural outlook and festivals and celebrations take place almost every month, adding spice to any diving holiday. In terms of gastronomy the island is a gourmand’s delight, with every conceivable culinary taste catered for. Visitors will most certainly eat well while on their diving holiday.

Visit Gran Canaria for a Great Scuba Diving Holiday

The island offers something for every diver, from protected bays to challenging deep wreck dives. Excellent underwater visibility and warm temperatures ensure relaxing and stress free diving. The island’s is home to numerous PADI Five-Star diving schools and equipment and expert tuition and guidance is readily available. For too long the island has been ignored as a world-class diving destination, all that looks set to change.

Diving Busselton Jetty, South West Australia

Busselton Jetty is the longest wooden jetty in the southern hemisphere and was built over a 95-year period from 1865. The main sources of income for the area in its 19th century heyday were timber and whaling. For this purpose jetties were built at the quaintly named towns of Wonnerup, Busselton and Quindalup in Australia's south west. Only the Busselton Jetty remains.

The jetty stretches a remarkable two kilometers into Geographe Bay. Closed as a port in 1972, the 138-year-old jetty has since been ravaged by both fire and cyclone. Its repair, and its subsequent protection, are due to the efforts of the local community who are now pushing for the jetty to be given full protected area status because of its rich marine life.

Its rickety wooden planking and lethal nails has that real old world charm of the colonial antipodes and it it is added to by the bright red train that now takes tourists down to the end of the jetty. But its underwater view is the real spectacle.

Leeuwin Current Brings Rich Marine Life to Cooler Waters

Every year in autumn and winter, the Leeuwin Current brings with it a narrow band of warm water down the West Australian coastline. It's this warm southerly current that’s responsible for bringing the incredible and diverse variety of tropical and sub-tropical species into Geographe Bay. Coral grows here at a latitude of 33 degrees south making it the most southerly coral growth in the world.

There have been around 300 hundred marine species recorded here. Huge schools of yellow tail scads cascade around the wooden pilings. Tropical and subtropical species litter the timber forest of the jetty’s legs. Soft coral and gorgonians deeply encrust every piece of timber, while ascidians hang in clusters off the pilings and sponges carpet any spare surface available. It is the best of any living reef. Groups of old wives fish sit completely still, suspended between timber legs while perch and gurnards happily navigate around the reef. A diver would commonly encounter around a dozen types of nudibranchs.

Busselton Jetty Underwater Observatory

Swimming in past the pilings towards shore, you reach the only underwater observatory in the southern hemisphere. Opened in 2003, you can be watched and snapped by tourists as they see you as part of the underwater seascape. It’s perfect for the non-divers in your party. They too can appreciate the extraordinary spectacle that is Busselton Jetty’s marine life. The jetty is already part of the Geographe Bay Marine Reserve Area and there are calls to make the area a complete no fishing zone, so protecting its remarkable variety of life.

Scuba Diving With the Numbfish

The shock from a Numbfish is not dangerous, but it makes this fish worth being aware of for a scuba diver.

The Numbfish is also known as the Numb Ray or the Electric Ray.

The Electric Shock of the Numbfish

The Numbfish has a unique organ on the top of the head containing a bank of 200 to 500 hexagonal cells. This organ establishes a voltage difference between the top and the bottom of the Numbfish, the top being positive and the bottom negative.

When a scuba diver, or another fish, touches this Numbfish, the voltage discharges through the scuba diver giving an electric shock.

The Numbfish can deliver a jolt of around 200 volts which can be enough to cause cramping in a scuba diver’s muscle in the arm of leg.

Within about 10 minutes, the Numbfish can deliver up to 50 successive voltage discharges. However, the voltage in the successive discharges falls to around 80 volts.

Why Does the Numbfish Have the Electric Shock Capability

It is believed that the Numbfish has the electric shock capability for two reasons:

1.As a defence mechanism. If a larger fish wants to take a bite, the Numbfish hits it with a sudden voltage.
2.As a way to catch its prey. Lying in the sand it waits for small fish, crabs, or worms to crawl across it. It then wraps its body around the prey and stuns them with an electric shock.
Details of the Numbfish

The Numbfish is a flat fish with the eyes on the top of its body. It has an oval body that elongates to the end with a smaller oval at the back with three small fins.

An adult Numbfish grows to around 700 millimetres (27 inches), with the width across its head being about the same as it is long. It is a fairly dull colour; dark brown on the top, and a yellow-white underneath.

It moves through the water in the normal manner of a ray by pulsating the outer edges of its body in a waving motion. It is a weak swimmer so doesn’t swim much, preferring to lie on the sea floor, partly buried on the sand waiting for its prey.

The Numbfish is viviparous, which means it gives birth to live young rather than laying eggs.

Apparently the Numbfish can swallow exceptionally large fish for its size. According to Ern Grant in Guide To Fishes a 600 millimetre Numbfish was once found with the tail of a 2.3 kilogram flathead poking out its mouth!

Where is the Numbfish Located

The Numbfish is a reasonably rare fish. That is, a scuba diver won’t see one on every dive. On coral reefs it is usually found half buried in the sand around the edges of coral bommies and rocky outcrops.

In Australia, the Numbfish is found along coastal waters in Queensland, including the Great Barrier Reef, and down the New South Wales coast. It has also been seen in the Great Australian Bight and along the West Australian Coast.

Scuba Diving Risks and the Numbfish

There is a slight risk for scuba divers in encountering a Numbfish. The most common way for this interaction to occur is if a scuba diver accidentally kneels on one that is hiding in the sand.

To avoid getting an electronic shock from a Numbray, scuba divers should pay close attention when settling onto a sandy sea-floor during a scuba dive. Good scuba buoyancy control can assist in achieving this.

The electric shock from a Numbfish is not strong enough to kill, but can be a catalyst for the start of other problems especially if the scuba diver gets a sudden fright and is already anxious underwater.

A scuba diver shouldn’t be concerned about sharing the waters with a Numbfish. These unique fish are simply one of the many animals that make scuba diving so fascinating.