Wednesday, April 29, 2009

Wreck Diving Certification

If you go to my blog on Scuba Diving - Learn to Dive Safe, you will see I have done 3 basic classes on Wreck diving. How to Evaluate, navigate, map, penetrate, and special considerations. Todays class in just on what doe it take to be a certified wreck diver for PADI.

As with most PADI classes you will get your course book with the associated DVD. It would be wise to read the text, watch the DVD, and do the required knowledge reviews before you do the dives. Some shops will have a brief class to discuss the material and go over the answers to the reviews.

After the book work it is time to do the required dives, There are 3 dives that must be completed prior to certification. I will go through each dive briefly.


This dive could be part of the Advanced dive certification. On this dive, you simply will dive on the wreck and do an overview, This will be on the exterior of the wreck. Get the general feel of the wreck, how is it sitting, and where are the hazards. In other words, just have fun diving a wreck. Watch the aquatic life that lives there. During this dive practice avoiding silting. Learn to navigate on a wreck by following the wrecks features (layout), feature references, and base line references.


Now we start to do some work on this dive. Go to my blog on Scuba diving yo learn more about this. On this dive you will navigate and map the wreck. Look to areas that you can penetrate later. Assess for stability. Look for possible hazards, points of interest, and general condition. Two Benefits to map a wreck are to simiply future dives and to help plan for a possible penetration of the wreck.


First you will practice how to use the penetration line on the surface. Then when you do the dive you will use the penetration lines along the outside of the wreck. This way you see how to handle the lines underwater. Swim out from the wreck and use the line as a retrieval line. Swim along the lines using your lights. Need to see how you handle all the gear at one time.


This dive can either be a tour wreck dive or a penetration dive. Some wrecks you dive on can not be penetrated. So you do not need to penetrate to get the certification. But It is nice if you could penetrate a wreck under the supervision of an instructor.

You need to learn how to avoid the 5 hazards of a wreck: This is why special wreck training in essential:
1. Loss of direction
2. No direct access to the surface
3. Restricted passages
4. Falling objects
5. Silt

Once you have completed all 4 dives, and the knowledge reviews, then you will awarded the Wreck Diver Certification.

Saturday, April 25, 2009

What is the Difference Between
Freshwater and Saltwater ?

Most people other than divers think there is a no difference between salt and fresh water.
As a diver you need to understand the difference and account for it when you change from one type water to the other. There are certain environments that tell you if a body of water is salt or fresh. Before you go on a dive, or trip, you need to find out and ask what the water is. You need to put this information into account as you make your planning. (Click on Picture to link to Phuket, Thailand diving - Great place to dive.)


Freshwater sites are lakes, quarries, springs, and rivers. Many of these require special training before you participate in them. Many also may be in the higher altitudes, again, you need special training to dive in higher altitudes.

Remember that in freshwater you need to consider currents, bottom compositions, limited visibility, thermoclines, cold water and entanglements.


Saltwater sites include for the most part oceans. These fit into 3 general classifications according to temperatures: temperate, tropical, and polar. The vast majority fits into temperate and tropical.

General considerations for these environments include waves, surf, currents, coral, boats, deep water, marine life and remote locations.

Enough about definitions and types, how does it effect me as a diver ? It has to do with buoyancy. First off fressh water weight less per cu foot than salt water. Just for referenec: freshwater weighs 62.4 pounds / cu foot, and saltwater weighs 64.0 pounds / cu foot. Ok , so.

Since freshwater weighs less than saltwater, you're not as buoyant for a given displacement. This means that if you dive in freshwater after you dive in saltwater, assuming you dive in the same gear and exposure suit, you'll need less weight.

So lets say in saltwater you dive with suit etc, and 15 pounds of extra weights than you go to do a dive in freshwater, you might be albe to do it with 8 - 10 pounds. Just remember that if you go from fresshwater to saltwater you will need to add on weight, from saltwater to freshwater, you will take some weight off.

The amount of weight to adjust will be based on experience in the water as far as comfort, the amount of salt in the water, and how you are breathing underwater that day. Just keep in mind that there is a difference between the weight you use in freshwater and saltwater are different.

Wednesday, April 8, 2009

What is AOWD ?

Simply put AOWD stands for Advanced Open Water Diver. What is this rating according to PADI ?

After the basic Open Water training the next logical step is to get the Advanced Open Water Diver certification. This rating consist of 5 dives that may span over two days or could be in 5 separate days. Basically you look at all the advanced specialties that PADI offers, and you are going to make the first dive of these specialties in 5 of them. However there is an exception. You must make the deep dive and the navigation dive as 2 of the dives. The other three can be a choice from a wide list of dives. Some of the choices are as follows: Altitude, wreck, night, dry suit, photography, search and recovery, drift, DPV (Dive Propulsion Vehicle), Enriched air, PPB (Peak Positive Buoyancy) and Boat just to name a few.

Once you have picked your 5 dives you must complete the text readings, and knowledge reviews in them. The advanced book will have all the other dives listed as well, you are only responsible for the 5 dives you pick.

Once you have done your 5 dives, the readings, and knowledge reviews you will awarded the Advanced Open Water Diver Certification card (or C-card).

But why do I need this certification. Remember I said you need to do the deep and navigation dives as part of you 5 total dives. The reason stems around those dives.

When you go on a dive trip, the DM(Dive Master) of the boat will ask for C Cards. If you have the Advanced Card they know you have had training in diving deep and navigation. Most dive operations take divers to spots that have the potential for a deep dive. If you had the training they know that they do not have to worry about your going deep and hurting yourself. They know you had the training.

Now for Navigation. In the Open water course we teach you to use a compass on the surface and underwater in a straight line. In this dive, we will teach you how to do a square, and a tri-angle. Every dive you do will have in it some form of navigation skills. Every diver need more advanced training in this area, and what you learn in the advanced course is that more advanced training. Not the end all to navigation, but a start.

Once these 5 dives are completed, you will be given credit for the first dive if you chose to go on and complete the entire specialty rating for those dives, Which I highly recommend.

Check out my sponsors links for soem FREE items.

Tuesday, April 7, 2009

Wreck Diving Limits -
Are You Diving to the Limits ?

When we talk about penetrating a wreck we, as divers, are always interested in the light we will have inside. Some of the light comes from the surface in the form of ambient (sun) light, while we provide other light from the dive lights we carry. Remember you should always carry one primary and at least 1, of possible 2 back up lights. The more backup lights the better.

During this blog we will talk about the limits established for diving in overhead environments. Here we are talking about a wreck, but it could, and does cross over to diving in a cave. In the near future I will have on my talkshoe show # 20348, Ron Carmichael who is an expert in training divers to dive in a cave. Look for dates of that interview in an upcoming blog and talkcast.

There are at least three limits we must observe.

1. Edge of light zone
When you enter the wreck and look back you will see some light, that is the ambient light coming from the surface/ Stay within this light that is available. Meaning that you should not penetrate if you can no longer see this light. If the dive is murky, then there will be less natural light entering the wreck. This also means, of course, that you should not make a penetration dive at night.

2. Linear distances of 40 meters /130 feet
In open water per PADI guidelines, a diver should not dive deeper than 40 meters / 130 feet. This is of course the recreational safe limits. There are courses that teach divers to dive deeper, but only attempt that under a certified instructor. Similarly, your maximum distance from the surface when penetrating a wreck should not exceed this same distance. This means that the depth of the wreck and penetration distance should not exceed 130 feet.

3. One third of your air supply
Whenever you dive in an overhead environment you dive and exit the wreck with 2/3 air and this includes the time it takes to surface. Simply put it this way, 1/3 to dive and go into the wreck, 1/3 to exit and go to the surface and 1/3 reserve.

This is known as the "Rule of Thirds". Saving two thirds of your air for exiting gives you more than of the most important factor you need to handle a problem inside a wreck: time.

You do not have to surface with 1/3 air, just exit the wreck with the air. You can dive around the wreck till an appropriate time to surface as you would if in open water. If diving deep, make sure you give yourself time to do a 15 feet stop for 3 minutes, ie a safety stop.

Monday, April 6, 2009

How To Handle STRESS Underwater

When you dive do you ever get Stressed ?
What steps can I take as a diver to help with underwater diver stress. When you encounter a potentially seious problem - whether your own problem or someone else's. There are four things to do to help with this problem.

Whatever caused this stress, just stop what you are doing. If you need to hold onto a rock, or plant your hand in the sand, do it. Just stop swimming. Remain still, conserve energy. If your stress is due to an increased breathing rate then stoppinmg is a good thing to do. Read my last blog on hypercapnia, and the first cause of that condition. Stopping is good.

Just breathe normally, concentrate on breathing in deep and slow. Remember that no matter what caused the stress, you still have air in your tank, and all is OK. This helps calm you so you can think clearly. If your buddy is breathing fast help him getr control of his rate. Stop, above, will help with this as well.

Think of the most direct, simple way to solve and overcome the problem.
If it was your breathing rate, then you have this under control. Are you tangled in lines or a fishing net ? What is the best way to cut free. Don't panic, all is ok.

4. ACT
Put into action the steps you thought through.

If the above does not relieve the situation after one or two tries. start over: stop, breathe, think and act.

These 4 steps seem like they may take along time to perform, where in reality, will only take a few minutes. More importantly, by training yourself to follow these steps, you avoid blind instinctive reactions that often lead to ineffective results. Through practice and training and by mentally rehearsing how to respond in various situations, you'll be able to act correctly, decisively, and calmly when facing a problem.

Thursday, April 2, 2009

Hypercapnia - Are You Diving High ?

Hypercapnia .... that sounds pretty serious. Yes it can be. Let's first define what this is and I will try to explain it. Definition: (also called hypercarbia) or excess carbon dioxide, can result from many causes. I will explain each to these.


Most common cause when a diver fails to breath slow and deep. If he does then you have small tidal volume (amount of air inhaled and exhaled during normal breathing), and high proportion of dead air to fresh air in the alveoli. Carbon dioxide levels in the alveoli and bloodstream increase, causing headaches, confusion, and a further accelerated breathing until the divers slows down and resumes deep, slow breathes. If unchecked, this elevated increase in carbon dioxide can lead to loss of consciousness.

In closed and semi-closed scuba gear, ( rebreaters ) and full face mask, have been associated with hypercapnia due to large dead air space (portion of divers tidal volume that plays no direct part in air / gas exchange.) However, in open circuit scuba used in recreational diving, hypercapnia due to dead air space is rare, but can happen.


If diver attempts heavy work underwater, muscle tissues can produce carbon dioxide faster than the respiratory system can eliminate it. This increase in carbon dioxide causes the respiratory center to stimulate a higher breathing rate to get rid of this increase. Because of the denser air breathed at depth, this requires more effort by the diaphragm and other muscles to overcome resistance from turbulence. This additional effort furture increases carbon dioxide production, resulting in yet a higher demand for increased breathing. This cycle continues until the diver slows down or stops activity, after which, the respiratory system catches up with the body gas-exchange needs.


This is holding your breath while scuba diving in order to extend your air supply. In reality, this techniques leads to an increase in carbon dioxide in their circulatory system, until it actually stimulates faster breathing and therefore helps to deplete air supply faster.


Contaminated air is rare in recreational diving. But it is always a good idea to breathe from your regulator prior to the dive to ensure the air taste "fresh". Part of the BWRAF procedure. The symptoms are the same as for improper breathing.

Bottom line: Breathe at a slow, deep, and unlabored rate. This will keep you safe, and allow you more "air" time underwater.

Wednesday, April 1, 2009

Responsible Diver Checklist

When you drive a car, there are certain things you must do to be considered a responsible driver. Just like in driving there also things we must do to be considered a responsible diver. The saying "ENJOY THE DIVE" will help you remember it.

E - Equipment well maintained and complete
Are you diving with old equipment ? When was your equipment last inspected and serviced ? You should have all equipment serviced on a yearly basis. The regulator needs to have all seals, and parts replaced every year. If you own tanks, again they need to be visually inspected yearly. They will drain all the air out, and look inside. Check the seals and refill. Has it been 5 years since you had the tank, you may need it to be hydro-tested.

N - Neutrally buoyant at all times
While at depth, you need to make sure that you are neutral to help protect the coral, plant life, and fish. Make sure your weights are positioned correctly to maintain a horizonatal position.

J - Just say no to drugs and alcohol
Goes with out saying, drugs and alcohol are not a good thing to do. It is even bad while diving. We, as divers, do not say we can not drink. But if you do drink then the last dive you made that day WAS your last dive. Alcohol predisposes you to DCS (decompression Sickness)

O - Observe conditions before the dive
What is the weather like the day of your dive ? What is the surf, or water conditions ? One of the hardest choices a diver has to make is whether to "dive or not dive". There is always the next day. Why put yourself in a potentially harmful position by diving in bad conditions, especially if they are beyond your training experience. Just stay out if you ever have a question on it.

Y - You've checked your air supply
Again another no brainer. Do the BWRAF procedure and check the air supply. Make sure you have enough for the dive and the air is turned on.

T - Take a safety stop before surfacing
Make a recommended stop at 15 feet for 3 minutes. This gives your body more time to "off gas" nitrogen before you exit.

H - Have an alternate air source
Must at least have an octopus set up in the "triangle" area. But better yet you should consider having a redundant air supply. An extra air supply with enough air to get you to the surface from any depth. My choice would be Spare Air. Check them out.

E - Enter and exit with care
You have a lot of gear on, so make sure you watch where you are walking. You do not want to fall and injure yourself before you get to the water. Pick good enter and exit points that are easy to navigate from keeping in mine safety.

D - Dive your plan
Every dive you go should be planned. The maximun depth, time, how you will swim the dive, who will lead, etc. Go over signals prior to the dive. Go over what you want to accomplish on the dive, ie see the wreck, feed the fish. Do not alter your dive plan, while underwater you may be thinking clearly and to alter it then, might put you and your buddy in an unsafe condition. Try to stay close to the plan you set.

I - I am a Responsible Diver
Make this statement to yourself that you are responsible and that you WILL do things to make you a responsible diver. Reading this is the first step towards that goal. Good for you.

V - Verify your buddy's equipment
Go over you buddys equipment prior to the dive by doing the BWRAF procedure. Check to make sure it is complete and working properly.

E - Enjoy the dive !
Above all this, make sure you enjoy the dive. The best way to do this is to make sure that you are properly trained for the dive you will make, that you have had plenty of rest prior to the dive, that you are mentally ready, and that you have planned the dive. If you do all the above you will have a Great dive.

Lets all be Responsible Divers. Until next time "Let's Get Wet".