The advanced open water certification allows divers to dive up to 30 meters. My class this time had three students, me and a young French couple. First we had to choose three of the five specialties to focus (the two mandatory are Peak Performance Buoyancy and Deep Diver), and we easily agreed on the other three: Wreck Diver, Night Diver, and Underwater Navigation. No DVD to watch, just lectures and five dives in open water.
After the morning lecture, we hopped into the boat for two afternoon dives. First dive was at Twins, specifically at Buoyancy World, an underwater artificial reef and training ground for scuba divers to increase their buoyancy skills, brilliant! Buoyancy World was constructed by the Save Koh Tao conservation group (more on them in a later story). The structures were made of non-toxic material that also encouraged coral and fish to settle. There were intricate swim-throughs, hoops, and other obstacles to practice. I was getting slightly better on judging distance and size underwater (another physics lesson forgotten: things appear larger and closer under water because light refracts when it travels from air into water), but even so, I still underestimated the size of the tank (it's bulky) and fins (they're long). I was getting more comfortable controlling my buoyancy through breathing (breathe in to ascend, breathe out to descend), so I would inflate and deflate my BCD less often. We dived for 53 minutes, longest dive so far, and up to 14.3m.
The second dive was at White Rock to focus on Navigation. The first exercise was to estimate the number of kicks it would take to swim 30 meters by following a string that our instructor placed on the sea floor; the second exercise was to swim a "square" 30 meters in length per side, going north, east, south and then west, using a compass. The visibility at White Rock wasn't very good that day, perhaps only 5 meters. The first exercise went OK for all of us. For the second exercise, I was so scared of losing count of my kicks and misreading my compass (worn like a watch on the wrist), I stared only at my compass and didn't realize the other two students were attacked by a trigger fish (those suckers were aggressive, very territorial), and were delayed in starting their square. I think I may also have miscounted the number of kicks on one of the sides, so even though I finished my square and thought I was back where I started, no one else was there. My initial reaction was "wow I'm a fast swimmer and must have finished early", but after a minute, still no one else swam to where I was. Now the proper thing to do at this point would be to search for about a minute, and if I couldn't find them, ascend to the surface slowly and safely, then locate and signal to the dive boat that I was OK. But of course I didn't remember any of this (it was only my fifth dive!), and instead I stayed underwater much longer than I should have, still thinking the others would find me. I checked my air and there was enough. I started to doubt that my "square" was correct, and didn't trust swimming in reverse using the compass to make matters worse. I stayed probably for as long 7 minutes, and finally decided I should ascend.
As soon as I surfaced, I saw the dive boat and waved. The instructor swam towards me and was pissed! He scolded me for not remembering the 1-minute rule and said I was missing for as long as 20 minutes (I doubted it was that long but wasn't about to argue, I knew I had F'd up). We swam back to the boat and I was so embarrassed! The other divemasters on the boat were about to start a rescue mission just as I surfaced. You can bet I would never forget how long to search for your buddy if lost again before ascending, tough way to learn but it worked!
