In 1980 the Ratchaprapha Dam in Khao Sok National park was created flooding the region creating what is now called Chiew Larn Lake. Surrounding the lake are large limestone cliffs characterized topographically with karst formations, dense jungle and diverse wildlife. The dam is popular for boat tours, kayaking, trekking and rock climbing and more recently as a technical diving destination used by Big Blue Tech. for conducting deep technical and cavern diving courses and explorations.
In February of 2009 6 technical divers from Big Blue Tech – a technical diving facility in Koh Tao, Thailand – discovered a sunken village 60m deep within the central region of the lake. This discovery would open up more opportunities for future technical divers giving them the possibility to conduct serious expedition diving in conjuction with their course. We complete all our courses on wreck liveabords, sunken village and cavern expeditions or alternatively on a luxury Similan Islands liveaboard (as of December 1st 2009).
Our journey begins with a plan to re-visit the village and explore some caverns. The expedition was a combination of a TDI Extended Range Course and TDI Cavern Course. The members of the expedition team are James Thornton-Allan ( Instructor) Christos Kardana (Assistant Instructor) Andy Holdaway (Technical Diving Intern), Panos Iosifoglou , Steve Jeffs and Nate Weiss who are completing their training.
With any expedition comes logistics and support planning. Emergency evacuation plans would have to be set before leaving Koh Tao to ensure the right people knew we were in the area and were able to respond in the eventuality of any incident. In addition, the success of the trip depended on a high level of equipment requirements and performance including primary and redundant light systems, gps, sonar and technical dive rigs.
Arriving at the national park pier we immediately noticed the water had rose 5m / 15ft from since our last visit. Loading the longtail proved difficult since the pier parking area was submerged. Everyone pictched in and in no time we were cruising along the lake towards our floating hotel as the sun came over the mountains silhouetting the mist trapped by the eclipsing limestone structures.
The hotel we would be based at is a modest “raft house” called the Prival Raft House providing basic accommodation, excellent food and stunning surroundings . This system off wooden planks and walkways proved a bit weak for Andy who by any standard is a rather large man and broke several boards daily. For the entire crew the resort was quiet, peaceful, beautiful and friendly making everyone feel very comfortable and welcome. Big Blue Tech booked the entire resort for this expedition giving everyone their own room and private area. This also meant we could take over the whole place to put our compressor, set up charging areas for flashlights, a dry area and a wet area for hanging wetsuits leaving the bar area for relaxing and reading and. A few poor customers arrived, to be quickly sent on their way by the roaring of the compressor and the hissing and testing of equipment.
Our first task was to get straight into the water for the cavern course, This was ideal since the diving that would come later would be pitch black and in fresh water those two conditions need a bit of practice. Everyone needed to tweak their buoyancy but by the second dive of the day everyone progressed through the skills and training with ease. Learning to become a cavern diver focuses on using a reel, laying a line during your dive, advanced dive planning, diver trim and control with more challenging skills to follow.
The following day waking with the rise of the sun and watching the mist roll over the lake was a peacful and refreshing way to get out of bed. The staff of the resort prepared a western style breakfast and then we were off for 2 more cavern dives followed by a night dive. The cavern dives were completed with ease, those who were already certified could explore the overhead environment while those under instruction practiced already learned skills and excelled at new ones. During the 5 hour surface interval James and Christos headed off to the dive site of the sunken village to tie on a permanent buoy line. The sonar showed 59m indicating the depth had increased with the change in water level. Christos had not dived in the morning so was fresh to head down to tie on. The gps mark was taken from a fixed reel and lift bag in February, this same reel was found 2 meters from the shot line showing excellent precision in the communication systems taken with us. Christos actually found that the sunken city was at 53m which is well within the training limits of the TDI Extended Range. For Steve who initially requested a DSAT Tec Deep Course was thankful he changed to TDI because of the 50m maximum depth restriction of the DSAT course. Christos tied onto a concrete pillar and returned to the surface. In opur absence the rest of the team had been sleeping, out kayaking and fishing.
Before the day would end it was time for a night dive. This dive would help the students get accustomed to task loading and skills in a similar environment without the obligation of decompression. This proved an essential addition to training on reflection the following day.
The following and 3rd day everyone was woken by screams and moans from the woods which was the wild gibbon monkeys in the trees swinging and calling to each other. Everyone compared how they normally get woken up from the sound of traffic to a phone ringing but this would be truly unique. The noise would continue for hours of the morning as we got ready for the next big dives. This morning we had some engine problems so rather then lose the chance to do two dives we decided to do one under the resort. This would give the team a chance at some decompression dives in the darkness while we waited for the boat to be fixed. The area under the resort is a dense forest littered with various things dropped from above. The most unusual things were clothes, a saw, pots and pans but the most common were simply beer bottles and bottle caps. The challenge for the divers was to navigate through the trees and dense canopy and still retain some idea of location and destination. Arriving safely at the surface the longtail was fixed, 3 hour surface interval and then off to the Sunken City.
The final dive of the day would be conducted in 2 dives with constant surface support at all times. As we descended the water colour and temperature changed drastically. The water on the surface was green and 31 degrees celcius. As we descended the colour would change from light green to dark green then smoky green to light brown then dark brown and eventually black. The temperature would drop 6 degrees in the darkness with crystal clear visibility. The water was so still and so dark you lost the sense that you were underwater at all. Since the terrain was very much man made it felt like you were flying through the ruins of an old town at night. Our descent had taken 5 minutes. As this was a new depth for the majority of the team it was essential to head down slowly to allow the effects of nitrogen narcosis to come on gradual rather then sudden. Arriving at the bottom we had 10 minutes left before we would head back to the surface. Reeling off the down line and using it as a guide for the students we headed towards the village passing the old discarded reel left behind from the last trip in February.
All the divers buoyancy was perfect, at no time did any diver make contact with the bottom. Bouyancy and trim had been one of the focuses throughout the duration of the course and that allowed a clear and controlled dive. After moving past man made structures one member had reached their turn around pressure so it was back to the down line to make our ascent. The most shocking feeling during the ascent was the change in temperature from quite cold to very warm causing most divers to signal to their buddy “hang on a minute, i’m going to the toilet”. We were wearing tropical 3mm wetsuits which meant the change in water temperature would effect you in every way possible. Completing the decompression schedule and the mandatory additional safety stop we arrived back on the surface with laughter and smiles all fighting to tell their own story of the dive. Back on the boat and returning to the resort we would plan the following and final days dives and get to bed early. One of the significant changes most notice from decompression diving is the fatigue which combined with fun in the sun can make many sleepy.
Big Blue Tech enforce and strict no alcohol drinking on all our technical training and trips. The students have been dry since the very first day they put on a twin set with us and proves to be the key in minimizing risk in recreational technical diving, no matter how extreme of repetitive it may seem. Although many were too tired to drink anything this evening we did give Kayleigh (Panos’ girlfriend) a lot of grief for having a cold beer with dinner. Regardless of the rules it was to early celebrate since we still had two more dives to complete. One more dive being lead by the instructor which would be their final training dive and a final experience dive where the student would change roles and gain some confidence by leading their own dive leader.
The final day of diving was met with overcast skies and strong winds. The early morning dive exposed the students to even greater bottom time which allowed them to explore further from the down line looking at all the concrete structures and becoming more accustomed to functioning in the harsh environment. While the dives were being conducted the base camp of diving operations was being broken down and packed away from the journey home. The large 50L tank of oxygen and emergency kit was the only piece not stored away. The second dive of the day and final dive of the trip was conducted without problems. The students were exposed to dive times in excess of an hour and bottom times exceeding 20 minutes at around 55m.
Returning to the floating resort the students were jubilant in completing their TDI Extended Range Course and earning the title of being self sufficient deep technical and expedition divers
The expedition concluded with a road trip back to the Surathani pier followed by a night boat back to koh tao where the staff rinsed all the equipment and scheduled the necessary servicing before the next trip in October.
“Cheers for the Teck Diving. I had a great time. In retrospect, the training was everything I was hoping for and more.” Steve Jeffs – TDI Extended Range Diver
