Yesterday during my second dive at Pulau Lang (Pulau Aur), I was leading 5 leisure divers (3 Advanced & 2 Open Water), we ventured to the less dived south-eastern tip of Pulau Lang. We planned for reciprocal navigation dive with a max depth of 24-26m and max bottom time of 30min.
Initial part of the descent and head out to south-eastern tip, was very clam and pleasant with visibility up to 20m. Once we hit 16m depth, current started to pick up from gentle to mild at depth of 24m. We were drifting for a couple of minutes before we started to ascent. We hang out for a couple of minutes at various depth (Multi-level stops), unfortunately the current started to pick at shallower depth. We won’t able to swim back to our dive boat.
So I signaled to my divers to surface up, as we were swimming at 5m swim for more 5 minutes to get back to our dive boat. I deployed my SMB before surfacing, as I knew we going to be drifted on surface too. Luckily, before I jumped into the water, I did tell the boatman where we were heading.
Before we surface up, we sighted 4 jellyfish in our direction, I signaled to my divers to look out for them. Once surfaced everyone fully inflated their bcd, and I fully inflated my SMB, asked one of the advanced divers to dunk his head underwater to check the jellyfish whereabout. We were drifting on surface as expected, so I asked the divers to swim perpendicular along the direction of current, till the surface current is gentle. We keep everyone close to each other.
I started to whistle, of course using a whistle, for our dive boat at the other side of Pulau Lang. No sign of the boat. After 5 mins, we saw 4-5 SMB shooting up the surface, the other group of advanced students with another instructor & 3 leisure divers, were also drifted out.
In the meanwhile, my divers were in high spirited, they started taking pictures of themselves and sharing on the dive we just had. It was only after 20 mins later, the dive boat came for us, after another group of open water students with their instructor completed their dive at the side of the island.
1. Plan your dive, dive to your plan – Yes. We did. Unfortunately the current were too strong.
2. Inform your Captain or Boatman where you are heading or your intend route of dive. Where is your exit point – Yes. We did. Unfortunately we won’t be able to swim back due to strong current.
4. Deployed SMB and get it fully inflated. SMB ideally as tall as you are.
5. Have a sounding device – Alarm or Whistle.
6. Stay together. If you have a Jonline, use it with everyone holding onto it. It is very useful during dive and on surface when the current is strong.
7. Face away from the sun.
8. Be patient.
9. ‘Do not point finger’ at anyone for the outcome.
10. Frequent look out underwater for any jellyfish or anything that going to harm anyone.
11. Keep the spirit up among the divers.
This photo was taken by one of the leisure divers during our drift on surface
I would like to share an incident last Sunday on Missing Diver. I was doing Peak Performance Buoyancy Dive with my 3 Advanced Open Water Diver students. Upon descent at Renggis Island – Pulau Tioman, a turtle was sighted, there was another group of 8-10 divers surrounding the turtle. So we waited for our turn to get closer to the turtle for a closer view.
The group of divers left and we have a close view of the turtle having his meal. He didn’t even bother about the divers surrounding him. We continue on for our dive, upon reaching the sandy bottom and coral, I carried out my head count. I have 3 Advanced Open Water Diver students and 1 leisure diver, including me will be 5 of us.
To my surprise, I have counted 6 divers including, it’s not 7th Lunar Month yet. Bloody hell, he was scrimping around me when I did the head count. I asked him if he was OK, he replied OK. I looked at his confused face, he was like not sure but still scrimping around to gain his buoyancy.
I took out my slate and wrote, I asked him, “R U LOST”.
He replied in signal, “I DUNNO”
I checked with him, “Which dive center is he from”
He wrote something “Free …..”
I signal to him to ascent, next moment I knew, he inflated his BCD and shoot up. It was too late to catch him, he went up very fast, I wasn’t able to react.
I hope he is fine, as I never heard and incident and accident report.
MISSING DIVER PROCEDURE
1. Search for your buddy for not more than a minute.
2. Safety Stop if required before Ascent to surface.
3. Reunite on surface.
Always stay close to your buddy, make a frequent check every once a while if he/she is still around. Do not panic when you discover you are lost or your buddy is lost.
Why can’t we breathe on pure oxygen underwater?
Yes. We can breathe pure oxygen (100%) underwater, but it’s only up to 6m in depth. After 6m, the oxygen become toxic to our human body. Remember the theory on Partial Pressure? (I try to be as layman as possible)
Atmosphere is made of 78.09% of Nitrogen, 20.95% of Oxygen, 0.93% of Argon, 0.039% Carbon Dioxide plus other traces of gases. Hence, we rounded it off to 79% of Nitrogen & 21% of Oxygen. Our body only utilities 5% of the 21% of Oxygen we inhale, the rest will be exhaled to the atmosphere again.
Partial Pressure of Oxygen on Sea Level = 0.21 bar. (which means 1 bar of atmosphere air, 0.21 bar is Oxygen, the rest – 0.79 bar is Nitrogen)
However when Oxygen is breathed under pressure, it will become toxic at Partial Pressure of Oxygen = 1.6 bar.
Sign and Symptoms of Oxygen Toxicity
Convulsion; Blurred Vision; Ringing in the ears; Nausea; Twitching; Irritability; Dizziness.
If you breathe 100% Oxygen, at 6m depth the Atmospheric Pressure is 1.6 bar, hence the Partial Pressure of Oxygen is also 1.6 bar.
However if you breathe on normal compressed air, to reach the Partial Pressure of Oxygen = 1.6 bar, you have dived to the depth of around 66m. Unfortunately, Recreational Diving is limited to 40m, don’t be foolish to dive to 66m.
Enriched Air or Nitrox
Any compressed air which Oxygen is more than 21%, it’s known as Enriched Air, this required you to take the PADI Enriched Air Diver Course or Nitrox Course by other agencies. The most common Enriched Air used are 32% or 36%.
Planning dive using Enriched Air is very important. You have to calculate the maximum depth and emergency depth depending your Partial Pressure of Oxygen.
Enriched Air Course is not a Technical Dive Course, it is still Recreational Dive Course, using different dive profile or rather dive table.