A PADI Open Water Certification allows you to dive independently, without direct professional supervision, to a maximum depth of 18 meters (60 feet). On 20th May 2023, I went to Tioman Islands, Malaysia with NUS Dive for my PADI Open Water Certification and here is all you need to know for your certification!
This blog captures
- All you need to know about the PADI Open-Water Course
- A short-summary of most Scuba diving equipment.
- My experience underwater and the marine life I saw [Spoiler: I saw a shark!].
PADI Open Water #
Professional Association of Diving Instructors a.k.a PADI, is recreational diving membership and diver training organization. It offers diver training to all levels, where Open Water course is the first beginner level course.
Pre-requisites to diving #
Although many may say, you don’t need to know swimming for diving, it’s NOT a correct statement!. Technically, you always have a supply of air from your tank underwater and you don’t need to swim to glide around because you’ll be buoyant. So why do you need to swim?
Swimming allows you to build $\text{CO}_2$ tolerance. Simply put, it allows you be confident enough to hold you breath longer. This directly reduced your anxiety when you’re out in the open sea or underwater. Given the unfamiliarity of the underwater environment and the numerous diving rules to be remembered, it is imperative to avoid feelings of anxiety or fear. Moreover, swimmers have easier time equalizing underwater (A concept you’ll learn later in the blog)
In fact, PADI requires you to know a decent level of swimming. Before you, gear up for the first time, your instructors will ask you to demonstrate the following in confined waters (pool)
- Swimming for 200m without stopping but at any pace
- Treading water for 10 mins, which means staying afloat in water without touching the pool edges or the floor. You can kick or gently swim too.
Other than knowing how to swim, unless you have medical conditions which prevent you from diving, you’re good to go!
PADI E-Learning #
Scuba diving has a lot to do with the environment and in turn the equipment. PADI requires every diver to go through it’s E-Learning Course before taking any dive. Although it’s very long [12-15 hours] it’s very important to take it seriously and go through it. There are 5 sections followed by quizzes, and a final quiz in which you have to pass 85% of the question.
To drive home the point of how important the E-Learning is let’s go though a situation covered in the beginner of the E-Learning
Effects of Pressure underwater #
At the surface the pressure is 1 atm. Underwater, which each 10m of depth the pressure increases by 1 atm. This linearly increasing pressure with depth causes a plethora of changes. (See figure below).
One of the major side effects of pressure change is the compression of air, and in turn the change of the volume of the air spaces. Humans are made up mostly of water, which can’t be compressed, so even at high pressures underwater, most of the our body is unaffected. However the 3 air spaces air space is subjected to compression and de-compression:
- Air inside the lungs
- Air inside the mask
- Air inside the ears
While descending, the air inside our ear-canals and the mask, gets compressed. The pressure from the water pushes down on the face and the ear drums. However since your tank supplied air at a density same as the depth you’re breathing it at, you’re lungs are automatically equalized. In fact if you blow out air though your nose into the mask, the mask also get’s equalized. Finally pinching your nose, and closing your mouth and trying to breathe out causes your ears to equalize. And you equalize every few meters before you feel pain.
During ascent, ears and masks take care of themselves if you ascent slowly. However, you must never hold your breath underwater while ascending. . Otherwise your lungs with expand and severely increases the risk of lung damage and decompression sickness.
Although, all the rules are easy to understand and intuitive to follow underwater, you must go though the entire E-Learning to know about all the things that can go wrong underwater. Knowing these actually help you reduce anxiety underwater even more, so win-win! 🏆
TL;DR:
- Finish your E-Learning before your first dive.
- Equalize Mask and Ear while descending
- Don’t stop breathing while ascending.
Confined Water Session / Pool Session #
Before going to the Open Waters, all diver must go though a confined water dives. Since I did it at my University, it was at the University Pool - 2m deep. The whole day 9am-5pm looks something like this
Swimming Test: 200m Swimming + 10 min Tread Water
Briefing about Scuba Equipment and Buddy Checks
First round Skill practice and demonstration
- Regulator Recovery
- Mask Clearing
- Buddy Share Air
Second round of Skill practice and demonstration
- Neutral Buoyancy
- Hovering
- Controller Emergency Swimming Ascent (CESA)
Third round of Skill practice and demonstration
- Finning
- Surface Swimming
Wrapping up
- Exiting the water
- Packing Scuba gear
We shall go into the details of each of them
Basic Level Skills #
These are the basic skills you need to know to recover from underwater panic conditions.
1. Regular Recovery #
While underwater, your regulator can come off and it’s of utmost importance to be able to recover it. That’s why this is the first skill you learn. A Recovery consists of reaching for the regulator and a purging of the regulator
- Over-the-head Reaching: Using your right hand, reaching over your head till you find the first hose, then follow the hose to your regulator (second stage)
- Side sweep: Tilt body right,with right hand touch your right thigh, your butt, your tank and do a big sweep.
You can use either of the methods. However, there will be residual water in your regulator, which you have to purge. You can purge by
- Blowing out hard
- Using the purge button.
Note: Remember to keep making small bubbles through your mouth, while recovering your regulator, because you’ll be holding your breath with can cause you start ascending quickly. Thus making bubbles ensures you’re not ascending quickly.
Note: These methods are so intuitive that you can perform them even with your eyes closed - in case you also had a mask and regulator problem at the same time.
2. Mask Clearing #
Underwater your mask can fog up or due to unforeseen reasons and come off partially. In such cases you must know how to flood your mask to clear the fog and recover a mask which has completely come off.
- Close your eyes when doing mask recovery, especially when you’re wearing contacts because it salt water strings.
- Apply shampoo to inside of mask before diving, this prevents the mask from fogging until the shampoo is washed off.
3. Buddy Share Air #
Emergency Buddy Share Air. Image Source: DAN
In the extreme situation of you running out of air, (doesn’t happen unless you have not kept your air in check), you might have to share air fom your buddy. Every diver has a spare regulator (In bright color like yellow) just for this kind of a situation.
You signal to your buddy that you’re out of air. Your buddy raises their hand to give you access to their extra regulator (which is generally tucked in their chest area in their BCD). You take their regulator, perform a roman handshake and ascend.
Note: These situations rarely occurs but when they do, they skills keep you prepared. So know them by heart but do not panic in anticipation.
Secondary Level Skills #
These are the skills you need to swim and dive underwater. Although these are less crucial to the basic skills, it’s more difficult to master these skills.
1. Neutral Buoyancy #
When underwater, your breathing pattern affects your buoyancy. When your lungs is full you start rising and when your lungs is empty you start sinking. The interesting thing about this is when you rise, pressure of water around you drops, which leads to increase of volume in your lungs, which makes you ascent even more. Same thing happens for while you sinking. Thus breathing in when you’re just about to sink and breathing out when you’re rising, counteracts the effects and makes you stay at the same depth. However this is tricker than it sounds and can only be mastered by practice.
Neutral Buoyancy is the skill of maintaining you depth using a consistent breathing pattern while in a horizontal position.
2. Hovering #
Hovering is the same as neutral buoyancy, but in the upright position.
3. Controller Emergency Swimming Ascent (CESA) #
This is again a safety skill and only to be used in the most critical of situations. When you’re out of air and you’re buddy is not near you, and you have to make a exit you perform CESA.
- You take in your take breath.
- You look up.
- You press the deflate button of your corrugator while pointing it upwards (So that expanding air inside your BCD while ascending is released).
- You make an ‘aaaa’ sound til force you to exhale a consistent stream of air and you fin to the top.
Note: this is very risky and almost certainly causes decompression sickness when ascending from a depth of 9m or below.
Open Water Dives #
Scuba Equipments #
Image Source: Designed by macrovector / Freepik
- Buoyancy Control Device (BCD): BCD is jacket with inflatable pockets inside it. You can manually fill the suit up by blowing into the corrugator hose or blow it up using the air from your tank via the low pressure hose. Corrugator is a pipe attached to the BCD though which you can inflate or deflate it using buttons on the pipes
- Weight Belt: Humans are buoyant in water by default - i.e human’s float in water naturally. Hence diver wears a weight belt around their waists to allow then to sink. The ideal weight is the minimum weight required, just enough to sink. It varies with the individual. I needed 3kg. In extreme emergency, if you drop your weight belt
- Cylinder: The air tank or cylinder container compressed air. The capacity is measured in bars of pressure. Usually we start with >200 bars. For 40-50min dive I usually consume 100 bars of air
- Fins: You wear fins so that it’s easier to glide underwater. It’s much more efficient that kicking with your bare leg.s Also it protects your feet when you touch the ocean floor.
- Mask: Your eyes can’t focus when in contact with water, so you need a mask to create a gap of air. Swimming googles don’t work because it doesn’t cover your nose. It’s important to cover your nose because you can equalize the pressure inside your mask by blowing out though your nose into the mask.
- Dive Computer: A dive computer is a specialized device used by scuba divers to monitor and calculate important diving information during a dive. It provides real-time data such as depth, dive time, decompression limits, and other vital parameters to ensure safe and efficient dives. This portable device helps divers track their nitrogen levels and plan their dives accordingly, enhancing safety and reducing the risk of decompression sickness.
- Wet Suit/Dry Suit: A wet-suit hugs your body and doesn’t allow ocean water to pass over your body directly, preventing your body from losing heat. However you’re still wet. Thus it’s ideal of diving in tropical climate. However, at colder waters, i.e. water below $22^oC$ you need a dry suit, which traps a thin layer of air, which keeps your warmer. However, since you now have an additional air pocket, you need special training for using dry suit to learn how to equalize the air in it.
- Cameras / GoPro: GoPros are great for adventure sports, but it’s not good for Scuba, unless you have a housing. GoPro are rated to be safe up-to depth of 10m but I wouldn’t not recommend you to take it without a SuperSuit or Protective housing. My friend used a GoPro Hero 7 Black with a third-party housing but at 10m deep, the housing gave way, and water seeped into every part of the camera, even inside the LCD. The GoPro died. Thus only use the official housing. Moreover, salt water corrode electronics, to remember to dip your GoPro in fresh water after the dive to let the remaining salts dissolve out. Learn more here.