What is the Open Water course?

The Open Water course is the basic scuba diving certification course taught by all certification agencies. There are small differences in course content between agencies, but they all cover the same basic skills and knowledge you will need to know as an independent diver.

Proper Weighting    Aim:To check that you are properly weighted in the water.

Reason to Learn: One of the main reasons for divers using too much air and bumping into coral and bottom features is not being properly weighted. By checking for proper weighting, or performing a buoyancy check, you can ensure that you have the correct amount of weight based on your body, exposure suit, and equipment. You should do this check whenever you change diving locations, exposure suits or equipment, or haven't dived for a while.

Step One: Make sure you do this check in water that is too deep to stand in and is the same as the water you'll be diving in - ie. a freshwater swimming pool won't help to check weighting for diving in the ocean (which is salt water). If you have a full cylinder you should add approximately 2 pounds (1 kilogram) to compensate for the fact that your tank will become more buoyant throughout the dive.

Step 2: Take a regular breath from your regulator and hold it - this is the only time in scuba diving that you're ever allowed to hold your breath.

Remember not to take a deep breath, just a regular breath.Holding your deflator above your head, let all the air out of your BCD by pushing your deflate button.

Step 3: You should float at eye level. Some people float at forehead level or chin level, although eye level is most common. The important thing is that you're not sinking and not floating, but remaining steady.

If you don't remain steady at eye (or other part of the head) level and begin to sink you have too much weight - remove a unit of weight and restart the exercise from Step One. If you float, you don't have enough weight - add a unit of weight and restart the exercise from Step One.

Step 4: Exhale completely - you should begin to sink in the water. If you don't sink, try to exhale even more. If this still doesn't work, you need more weight - add a unit of weight and repeat the exercise from Step One.

It's important not to kick your fins while exhaling as this can push you up and make it seem like you're under-weighted when this is not the case. Try to keep your body quite still while performing this exercise.

Step 5: Giant Stride Entry : To enter the water safely using the giant stride method.

 Reason to Learn

The giant stride entry is the best entry whenever you're entering deep water off a stable platform. A stable platform may be either a boat with a dive platform, a dock, or even the side of a swimming pool. If you dive from larger dive boats this is the entry you'll most commonly use.

 How:

1. Put on all of your equipment according to the method used on your boat. For example some larger boats will ask their divers to put all equipment on including their fins before leaving their tank rack, other boats may ask divers to put their fins on closer to the entry point.

2. Ensure that your mask is on properly, your regulator is in your mouth and all other equipment is in place.

3. Stand at the edge of the boat with one fin over the edge and the other at a 45 degree angle to your body. If the boat is rocking you may need to hold a rail or ask another diver or one of the boat crew to help you balance.

4. Inflate your BCD so that it is a third to half full of air.

5. Look down into the area where you're planning to enter the water to make sure it's clear of other divers and potential hazards.

6. Place the palm of your right hand over your regulator with you index and middle fingers firmly against your mask. Hold your weight belt buckle with your left hand.

7. While looking straight ahead towards the horizon take one big step forward with your back leg.

8. Once you've entered the water you should float comfortably on the surface. If you don't, inflate your BCD until you do.

9. Once all is OK give the OK signal to the boat.

Step 6: Ascending: Safely ascend to the surface after a dive

Reason to Learn: Every dive will end with the need to ascend to the surface and it's important to make sure that every ascent is a safe ascent.

1. Signal to your buddy and agree to end the dive.

2. Ascend to 15 feet (5 meters) at a rate not exceeding 30 feet/9 meters a minute (some dive societies suggest 60 feet/18 meters a minute but I'vechosen the more conservative rate for increased safety). Use your depth gauge to make sure you're not ascending faster than this rate.

3. At a depth of 15 feet (5 meters) perform a safety stop. If you're diving in an environment with surface hazards such as speed boats or jet skis you may want to launch a surface marker buoy. This may also be standard practice to make it clear to the dive boat where the divers will surface.

4. At the conclusion of the safety stop signal your buddy and agree to surface.

5. Extend your deflator above your head and be prepared to release air from your BCD as you ascend.

6. Look up and slowly kick to move up in the water. Vent air from your BCD as needed in order to ascend at a rate no greater than 30 feet / 9 meters a minute.

7. Rotate in the water as you ascend so you can be aware of all parts of the surface above you. Listen for the sound of approaching boats or other potential hazards.

8. When you reach the surface, inflate your BCD and establish positive buoyancy.

9. Signal the boat or shore that you are OK.

Controlled Seated Entry: To safely enter the water using a controlled seated entry.

With all equipment in place sit on the edge of the platform with your legs over the edge. Make sure your mask is on and your regulator is in your mouth. Your BCD should be partially inflated (one-third to half full). Place your hands on the edge of the platform next to you.

Push off from the edge with your arms and move forward into the water, turning towards the platform as you drop in to the water. You should enter the water facing towards the platform.
As long as you push away from the platform you should have no problems clearing the platform and entering the water smoothly.

Establish positive buoyancy by inflating your BCD and when all is OK give the OK sign to the boat, shore, or other platform.

whale shark

Whale Sharks are easily recognized by their immense size and a two-tone pattern of light spots and lines on a base coloration ranging from gunmetal grey to black to dusky blue, mocha brown, or bronze upper surface and a white underbelly.

The whale shark has a broad, blunt head; three prominent ridges running transverse along its body. It's enormous mouth is located at the front of the head, and can be opened wide to filter large amounts of water for small fish, squid, crustaceans, and other plankton organisms. The Whale Shark is ovoviviparous and gives birth to live young measuring approximately 70cm in length. The Whale Shark is not only the largest shark species, it also has the largest litter size of all sharks.

Very little is known about the habits of the Whale Shark. Sub adults may live in small groups, but these are seen only very rarely. Adults are usually solitary and nothing is known about the way these giants find each other, or how and where their mating occurs.

Whale Sharks are on many peoples "must do" list and in spite of their general scarcity, encounters with these gentle giants can be had off Sodwana Bay annually between October and April due to their natural migratory patterns.Globally, Whale Sharks also appear often around the Seychelles, Similan Islands (Thailand), Christmas Island, Ningaloo Reef (Western Australia), India, Sri Lanka, Belize, Mexico, Kenya and Mozambique.

Physical Characteristics

The largest shark, which was accurately measured at 12,18 meters (40 feet, 7 inches) in length and weighing a hefty 11 metric tons by fishermen who netted a specimen off the coast of Bombay in 1983 and has been less accurately reported in other instances at 18 meters (60 feet).  Whale Sharks are estimated to be approximately 70 cm at birth.  Very little information exists of juveniles measuring less than 3 m in length as the majority of encounters occur with animals between 3 - 8m.

Epidermis

The skin of an adult whale shark may attain a thickness of over 100mm, limiting its possible predators to great white sharks, tiger sharks and orcas, and although none have been observed attacking a whale shark, some individuals show scars and bite marks from apex predators. Scientists call the contrasting coloration of a dark upper surface and light lower surface counter shading, a trait indispensable for stealth and protection. Another possibility is that these pigment patterns could be an adaptation for radiation shielding, important in a species that may spend a significant proportion of time in surface waters possibly exposed to high levels of ultraviolet radiation.

Eyes

Whale Sharks eyes are situated in front of the pectoral fins and gill slits where the polka dotted, dark upper surface joins the snowy underbelly, and two rounded recessed orifices on either side of the head.  The larger of the orifices houses an unblinking eye the size of a golf ball.  The eyes show no expression other than the wide-eyed stare of a large black pupil that swivels to follow any activity going on around it.  

If an object approaches the eye too directly the eyeball swivels backward into the cavity and a tough flap of skin slides forward to cover the opening to the vulnerable sensory organ.  
Once the shark perceives that the threat has passed, the skin flap retracts and the eye returns to its wide-open stare.  
Other shark species posses a similar shielding eyelid (called a nictitating membrane) which slides forward to protect the eye, but the whale shark’s sight protection adaptation is unique and is as yet unclassified.

Spiracle

A slightly smaller opening spaced back from the eye and ahead of the gill slits marks the site of the spiracle chamber.  The spiracle functions as a vestigial first gill slit, allowing water to be taken in and oxygen extracted, whereupon the oxygenated blood is pumped directly to the eye and the brain via a separate blood vessel.  

More commonly associated with sedentary, demersal sharks, sawfish, guitarfish and stingrays. The spiracle in this non-bottom-dwelling shark was one of the criteria that led taxonomists to make the whale shark the sole representative of the family Rhincodontidae in the Orectolobiformes order (an order comprised of nurse, zebra and carpet sharks.)  Whale sharks and other Rhincodontidae also have five gill slits, two dorsal fins, a single anal fin and a mouth termination in front of the eyes.

Mouth

The mouth extends across the width of the flat, blunt snout and ends well before the eyes.  
A mouth running the width of a whale shark’s head can reach tremendous proportions: the 12,18m specimen’s head measured 1,36m across, in the slack repose of death; alive and in the process of feeding, it can possibly extend two or three times that width.

Smell

Like bottom-dwelling sharks, the whale shark has twin nasal slits and sensory barbells (a trait it shares with the nurse shark) in front of its blunt snout on the upper surface above the mouth.  

In sharks, the nasal openings do not lead to the mouth nor do they play any part in respiration, their purpose is to augment the shark's sense of smell, enabling it to detect prey without relying on sight.  

The majority of other shark species have a ventrally located mouth and an elongated snout, which provides a greater surface area for the receptors of the ampullae of lorenzini - the sensory organs which detect weak electronic fields and provide sharks with sensory information when their vision is hampered.  

Placed, far forward and extending over the mouth, the whale sharks barbells augment the ampullae of lorenzini and signal the location of prey, guiding the whale shark's mouth towards its reward.

Teeth

Some scientists believe the whale shark's teeth to be vestigial.  Their function has not been observed, but it seems probable that they are used in processing larger food items, such as small tuna and mackerel that are occasionally captured but are too large to pass through the whale shark's gullet.