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Friday, January 15, 2010
Monday, January 4, 2010
Nice photos this week
Sunday, January 3, 2010
Diver Safety - Nitrogen Narcosis
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.
Source: Bruce Iliff - Suite101.com
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.
Source: Bruce Iliff - Suite101.com
New Certifications this week
1st Divemaster of 2010!
Saturday, January 2, 2010
Happy New Year Diving
OK so we know its raining and the vis is lower, but it doesnt stop us diving and finding some cool stuff. This pygmy seahorse was as small as the tip of my nail on my little finger!
This week highlights:-
Dili Rock - Huge Dendedoris tuburculosa, cuttlefish and two ornate ghost pipefish
The Pinnacle - Turtle, sea snake and blue spotted stingray
Tasi Tolu - The usual suspects, 4 seahorse, 2 cuttlefish, mantis shrimp and an ornate ghost pipefish
Secret Garden - Great vis, blue spotted stingray and Maori Wrasse
Marble Rock - This wonderful little pygmy seahorse
Photo -Thanks Rob Burfield
This week highlights:-
Dili Rock - Huge Dendedoris tuburculosa, cuttlefish and two ornate ghost pipefish
The Pinnacle - Turtle, sea snake and blue spotted stingray
Tasi Tolu - The usual suspects, 4 seahorse, 2 cuttlefish, mantis shrimp and an ornate ghost pipefish
Secret Garden - Great vis, blue spotted stingray and Maori Wrasse
Marble Rock - This wonderful little pygmy seahorse
Photo -Thanks Rob Burfield
Tuesday, December 29, 2009
Diver Safety - Night Diving Tips
Go at Sunset
Many dive boats will leave for a night dive right before sunset. That way you have light to get your scuba gear ready. It also feels less intimidating (to me anyway) to go out while there is still some light left.
Likewise, if you are doing a shore dive, plan on hitting the water right before the sun sets.
Even though you will have some light above the water, it will still be pretty dark underneath. And by the time you surface, it will be dark out.
Dive a Familiar Site
If this is your first time scuba diving at night, try and go to a site you are familiar with.
If you are thinking of doing the night dive, sign up to do a dive at the night dive site during the day. This way you will have some idea of what the area is like and may feel less apprehensive.
Keep it Shallow
A night dive is typically a shallow dive. I would say 20 meter is probably max with 10-15 meters more the norm.
Get Some Light
You obviously need some dive lights when you are doing a night dive. It's best to have a primary light and a backup light in case the first light fails. The secondary light can be small and could fit into your pocket.
You don't need the biggest and brightest light you can find. In fact, it is fun, once you get accustomed to diving at night, to turn your light off and let your eyes adjust to the dark. You'll be amazed at what you can see. Of course, it is up to you and get the light you would feel comfortable with while diving at night.
If you don't want to turn your light off underwater (I've never had a problem turning it back on but you never know) you can always face it into your BC so you get the same effect.
Attach It
You will want some method of attaching that dive light to you. That way if you let go, it won't sink to the bottom, never to be seen again. A lanyard or stretchy cord (or whatever you are comfortable with) work fine. Which reminds me of one of the next night scuba diving tips:
Use Reflective Tape
One thing I have seen which I think is a good idea is to mark your lights or other paraphernalia with reflective tape. That way if you drop something, you be able to spot it once the light shines on it. I've seen people put an X on their BC or tank so their dive buddy can tell it's them. Something worth considering.
Take it Slow
There is alot to see at night. You will see a whole different world underneath at night than during a day. Take your time and look in those nooks and crannies.
The reef also looks brilliant and colorful in the beam of your light. Much different than during the day when you are diving deeper and the colors are absorbed.
Descend Feet First
It is best to descend feet first and look down when you are descending. You can shine your light underneath you (just make sure you are not shining it in someone's eyes) to see where you are going so you don't hit or disturb the coral. More night scuba diving tips:
Get Familiar With the Hand Signals
When you are night scuba diving, you need to discuss the hand signals before you begin your dive. Since it is dark down there, your buddy won't be able to see your hands.
The divemaster will probably tell you what signals to use. If they don't, just ask. There is nothing wrong with that.
A typical way to use hand signals is to shine your light on your hand so your buddy can see them. Another common night diving signal is to move your dive light in a circle to signify "OK." Moving it up and down or back and forth can signify yes or no.
Whatever you choose to use, just make sure you clarify before you begin the dive. Which leads into one of the next night scuba diving tips:
Watch Where You Aim That Light
Be aware of where you aim your dive light. If you put the full force of that light beam into somebody's eyes, you can momentarily blind them. It will take a little while for that diver to adjust his night vision again. So be careful.
Keep an Eye on Your Gauges
If you are new to scuba diving at night, you may go through your faster than your would during a typical daylight dive. This could be compensated for by the fact that a night dive is usually shallow, but just be aware of your air at all times. Of course, this is one of those night scuba diving tips that is applicable to day scuba diving too.
Mark Night Diving Entry/Exit Points
If you are doing night scuba diving off a boat, the boat should have a flashing strobe light attached to it so it is easy to find. As you are ascending, make sure you are looking up and know where the boat is so you don't bang your head.
If you are doing a shore dive, you should also know how to mark the night diving entry/exit point. The most common way is to place lights on the shoreline. You should use more than one to make it easier to spot. You could have 2 close together and 2 close together but further down the shoreline. Or whatever configuration works for you.
It also doesn't hurt to have someone on the shore to make sure the lights don't go out (or somebody doesn't swipe them). And last, but not least, the last of the night scuba diving tips:
Keep an Eye on Your Buddy
If you happen to lose sight of your buddy, one way to find him would be to shut off your light and look for the glow of his light. He shouldn't be that far from you and you should be able to see his light.
Another, and pretty much opposite way, is to turn a full circle while pointing you light outward. You might be able to see your buddy in the beam or he might notice the movement (if he hasn't noticed you are gone yet).
If the boat has to come pick you up after you have surfaced, shine the light on yourself so the captain can see you.
And that the last of my night scuba diving tips.
If you haven't done night scuba diving, you should really give it a try. It's a different experience and isn't difficult. You just have to get used to it, like all new things. You'll see lots of new creatures and habits to add to your memories. So give it a try. I hope these night scuba diving tips will help make your first night dive a more comfortable experience.
Source: www.scuba-diving-smiles.com
Many dive boats will leave for a night dive right before sunset. That way you have light to get your scuba gear ready. It also feels less intimidating (to me anyway) to go out while there is still some light left.
Likewise, if you are doing a shore dive, plan on hitting the water right before the sun sets.
Even though you will have some light above the water, it will still be pretty dark underneath. And by the time you surface, it will be dark out.
Dive a Familiar Site
If this is your first time scuba diving at night, try and go to a site you are familiar with.
If you are thinking of doing the night dive, sign up to do a dive at the night dive site during the day. This way you will have some idea of what the area is like and may feel less apprehensive.
Keep it Shallow
A night dive is typically a shallow dive. I would say 20 meter is probably max with 10-15 meters more the norm.
Get Some Light
You obviously need some dive lights when you are doing a night dive. It's best to have a primary light and a backup light in case the first light fails. The secondary light can be small and could fit into your pocket.
You don't need the biggest and brightest light you can find. In fact, it is fun, once you get accustomed to diving at night, to turn your light off and let your eyes adjust to the dark. You'll be amazed at what you can see. Of course, it is up to you and get the light you would feel comfortable with while diving at night.
If you don't want to turn your light off underwater (I've never had a problem turning it back on but you never know) you can always face it into your BC so you get the same effect.
Attach It
You will want some method of attaching that dive light to you. That way if you let go, it won't sink to the bottom, never to be seen again. A lanyard or stretchy cord (or whatever you are comfortable with) work fine. Which reminds me of one of the next night scuba diving tips:
Use Reflective Tape
One thing I have seen which I think is a good idea is to mark your lights or other paraphernalia with reflective tape. That way if you drop something, you be able to spot it once the light shines on it. I've seen people put an X on their BC or tank so their dive buddy can tell it's them. Something worth considering.
Take it Slow
There is alot to see at night. You will see a whole different world underneath at night than during a day. Take your time and look in those nooks and crannies.
The reef also looks brilliant and colorful in the beam of your light. Much different than during the day when you are diving deeper and the colors are absorbed.
Descend Feet First
It is best to descend feet first and look down when you are descending. You can shine your light underneath you (just make sure you are not shining it in someone's eyes) to see where you are going so you don't hit or disturb the coral. More night scuba diving tips:
Get Familiar With the Hand Signals
When you are night scuba diving, you need to discuss the hand signals before you begin your dive. Since it is dark down there, your buddy won't be able to see your hands.
The divemaster will probably tell you what signals to use. If they don't, just ask. There is nothing wrong with that.
A typical way to use hand signals is to shine your light on your hand so your buddy can see them. Another common night diving signal is to move your dive light in a circle to signify "OK." Moving it up and down or back and forth can signify yes or no.
Whatever you choose to use, just make sure you clarify before you begin the dive. Which leads into one of the next night scuba diving tips:
Watch Where You Aim That Light
Be aware of where you aim your dive light. If you put the full force of that light beam into somebody's eyes, you can momentarily blind them. It will take a little while for that diver to adjust his night vision again. So be careful.
Keep an Eye on Your Gauges
If you are new to scuba diving at night, you may go through your faster than your would during a typical daylight dive. This could be compensated for by the fact that a night dive is usually shallow, but just be aware of your air at all times. Of course, this is one of those night scuba diving tips that is applicable to day scuba diving too.
Mark Night Diving Entry/Exit Points
If you are doing night scuba diving off a boat, the boat should have a flashing strobe light attached to it so it is easy to find. As you are ascending, make sure you are looking up and know where the boat is so you don't bang your head.
If you are doing a shore dive, you should also know how to mark the night diving entry/exit point. The most common way is to place lights on the shoreline. You should use more than one to make it easier to spot. You could have 2 close together and 2 close together but further down the shoreline. Or whatever configuration works for you.
It also doesn't hurt to have someone on the shore to make sure the lights don't go out (or somebody doesn't swipe them). And last, but not least, the last of the night scuba diving tips:
Keep an Eye on Your Buddy
If you happen to lose sight of your buddy, one way to find him would be to shut off your light and look for the glow of his light. He shouldn't be that far from you and you should be able to see his light.
Another, and pretty much opposite way, is to turn a full circle while pointing you light outward. You might be able to see your buddy in the beam or he might notice the movement (if he hasn't noticed you are gone yet).
If the boat has to come pick you up after you have surfaced, shine the light on yourself so the captain can see you.
And that the last of my night scuba diving tips.
If you haven't done night scuba diving, you should really give it a try. It's a different experience and isn't difficult. You just have to get used to it, like all new things. You'll see lots of new creatures and habits to add to your memories. So give it a try. I hope these night scuba diving tips will help make your first night dive a more comfortable experience.
Source: www.scuba-diving-smiles.com
Friday, December 25, 2009
Xmas Day Party 2009 - DTL/Castaways
Tuesday, December 22, 2009
Monday, December 21, 2009
Dive Log - Tasi Tolu Dec 09
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