I checked my computer. We had been at 30 meters for about twenty minutes and my screen was flashing “High Nitrogen – Go Up”! I checked it again: 1000 psi of air remaining. My breathing was good. Slow, moderate breaths as I hovered about 3 meters off the bottom of the Andaman Sea, about 50 meters off the coast of Koh Tachai – a small island north of the Similan Island chain west of Peninsular Thailand.
Off to my right a large trevally dove into a group of schooling runners and emerged with a fish stuck in its mouth. I chuckled to myself as it looked like the trevally was smiling…
I gave a couple taps on my tank,”Ting – Ting”, with the large brass ring I carry for the purpose and signaled to Luca (our guide) that I was nearing a mandatory decompression stop and that I needed to get off the bottom and head up a few meters.
For those who are unaware: A decompression stop occurs when one has been diving at depth long enough for compressed nitrogen to build up in their tissues to such a degree that to ascend directly to the surface would cause their blood to boil, joints to swell until bursting and in worst cases cause a rapid and increasingly agonizing death. Not exactly what I had in mind when we set off on this scuba diving adventure two days before.
Our dive plan did not include any decompression obligations so going over our nitrogen limits could mean serious problems. Running out of air before finishing a decompression stop would mean shooting to the surface and skipping the necessary nitrogen off-gassing. i.e..getting “bent” – the worst-case scenario for a diver!
We had left the dive shop in Khao lak on Wednesday aboard the Similan Explorer bound for the Similan Island chain on a short, four day scuba diving expedition. The Similan Islands are famous as the “Best Diving” in the Andaman Sea.
While the Similan Islands may have a lot of cool things to see and do, the truth of it – if I am honest – is that I was searching for Manta Rays! Heck…who am I kidding – we were all searching for Manta Rays!
Manta Rays are one of the pinnacle creatures to encounter on a SCUBA dive; right up there with whale sharks, dolphins and humpback whales. While there are some places in the world to see mantas that make it easy by feeding or luring them, the real thrill is encountering one organically, in the wild!
I looked again at my dive computer: 850 psi…Still flashing “High Nitrogen – Go UP”, flashing, flashing. I signaled my dive buddy that I was getting critically close to a decompression obligation and that I was going up to around 17 meters to get some of this nitrogen out of my system. (rising up slowly in the water column reduces the pressure on the body slowly, allowing some of the nitrogen in your tissue to release out of your body slowly so that it doesn’t gassify in your blood stream!).
I gave another “Ting-Ting” and Luka looked over. I signaled my situation and, with a flip or two of his fins, he glided over to me. I showed him my dive comp and he showed me his…holy crap! He was in the same situation! It was time to rise up, but we had had high hopes of encountering a manta at this spot and depth. Nobody wanted go up but we just couldn’t avoid it.
We all starting exhausting our buoyancy compensators and rose up to around 15 meters. We all looked out into the deep blue, still hoping to catch a glimpse of the mysterious and elusive Giant Oceanic Manta Ray!
Tuna and trevallies schooled and darted in the half-blue / white of the sun mixing into the colors of the ocean. My eyes were scanning left…right…nothing. I glanced at my dive buddy and signaled “how much air do you have?”
“600 psi”, came the reply. I gave a look…I still had 750, but my buddies time was up, so mine was too (that’s the rule). I signaled Luka…”Going up, low on air…safety stop for five minutes at 5 meters.” Luke nodded in agreement and signaled the group to gather up and head for 5 meters for our safety stop.
At five meters we all hung there, motionless, scanning into the blue. Any experienced diver will tell you that the safety stop can be one of the most unexpected pleasures in diving. Many times, as I have hung in the blue, waiting for my gas levels to come down, I have been surprised to see some magnificent creature come drifting out of the blue to hang out or give a show while I floated on my stop. Most times it is something simple like Hawksbill turtles or Giant Southern Stingrays, but other times it might be a Spotted Blue Eagle Ray, or a pod of dolphins! I kept scanning….nothing.
As our five minutes expired we all started heading up to officially surface and end the dive.
Just then I heard the rapid “beep, beep, beep, beep” of a dive alarm! I looked at my computer…not me! I looked at my buddy and pointed at her comp…”not me!”, she shook her head. As I spun around to check the other divers I saw Luca checking the computer of one of the other divers in our group. He gave her the “deco” sign, which meant she hadn’t been watching her tissue levels and had let too much nitrogen build up in her system. Now she would have to stay down for another amount of time to let it get out of her system slowly.
How much time? Well, that depends on how much nitrogen she had built up in her tissues. Since I hadn’t heard an alarm as we approached the initial safety stop, I presumed she would have another 5 to 8 minutes of obligation. (Had she much more nitrogen in her system the first obligated stop would have been deeper…probably around 12 or 13 meters or so for, maybe ten minutes ; so no alarm on the trip to 5 meters was a good sign).
The rest of us all nodded our understanding and signaled that we would rise up to the surface and hang on the buoy that Luca had sent up when we started our safety stop.
As we floated on the surface I was explaining the deco stop to one of the other divers and began worrying a bit about their air supply. Luca had as much air as I did when we started the ascent to 5 meters, but I had no idea about the other diver’s air situation. If they ran out of air before the deco stop, they would have no choice but to surface and risk getting “bent”.
“I had better go down and check on their air situation” I said to my buddy. If they needed air, I could swim ahead to the boat and get the boat to “hang a bottle” at 5 meters for them to breathe on (which would have been standard procedure if we were “planning” a deco dive – except, we hadn’t!).
As I was putting my mask back on and grabbing my regulator my buddy let out with…”Hey, the buoy is taking off”!
“What?”…I looked at the buoy and it was off and running…”Oh shit!” I thought: They’re running out of air and are making a run for the boat! Just as I was thinking this the buoy veered away from the boat and headed out towards the blue…
“He’s pointing at something!” my buddy yelled!
I looked into the depth and could see Luka swimming like a medal winner and pointing and jerking his hand out into the blue.
“Is it a manta”? she said half asking and half prognosticating….
I dumped some air from my BC (buoyancy compensator) so I could get off the surface and use my fins to my advantage. We all swam our asses off trying to catch up with Luka! Swimming, swimming…I was slowly dropping back down… 4 meters….6 meters…
Then it came into view…I swallowed my breath when I realized the shape of it…
The Giant Oceanic Manta Ray came crashing out of the dark blue Andaman sea with the grace of a slow motion ballerina…gliding effortlessly in the warm, sunlit waters of the sea. It swam closer and closer and then veered off to its left. I could see the cleaner fish, catching a ride on its back, the wing tips barely moving, but all the while propelling the giant at (compared to our futilely kicking legs) high speed. For a moment it looked as if it would swerve around back towards us, but instead it dived down and away, back into the blue haze just as it had emerged.
It was an awesome sensation to have been in the presence of such an amazing, serene creature. To imagine the depths to which it has cruised, the sights it must have seen in its very long life. I couldn’t help but wonder how many humans it had ever seen in its life. Were we the first it had ever encountered? Were we the first to ever lay eyes on this ray? The answer is most likely “no”, but one can’t help but to ask these kinds of questions when one considers the immensity of the oceans.
The Giant Oceanic Manta has a range of around 1/2 BILLION cubic Kilometers. That is a LOT of space! Given that there are new species being discovered every day, it is not inconceivable that one might a spot a specific Manta for the first time ever… Anyway…who knows.
The next day we spotted another giant manta, this time it came even closer, swooping right over our heads before turning and gliding out of view.
I hope the retelling of this story can, in some way, convey the excitement that scuba diving has to offer and help to explain why I love it so much. Maybe you would like to try it out? Hit me up and maybe we can go diving together some time…get in a little BJJ later (a couple hours later, at least…to avoid boiling our blood and all 🙂 )
Until next time, Oss and good training (and diving).