Thailand – Australia – United Kingdom

Posts tagged “wrecks

HTMS Sattakut (LCI-742) Shipwreck on Koh Tao

Koh Tao, Thailand

Big Blue Tech observed the Thai navy sink one of their own ships today on Koh Tao to provide an artificial reef and wreck diving resource just off the shore from our resort.

The HTMS Sattakut was origionally owned by the US Navy. During World War II USS LCI(L)(G)(M)-739 was assigned to the Asiatic-Pacific Theater and participated in the assualt and occupation of Iwo Jima and Okinawa in 1945.

Plans to dive the new wreck are already underway with undoubtedly hundreds of divers just waiting for the conservation society to finish counting the sea stars and let us have at it. We’re expecting a chance to dive it within the week.

The ships unique bow design allowed troops to assault beaches in the security and shelter of it’s forward guns and Armour. This gives the wreck an unusual appearance.

Displacement 246 t.(light), 264 t. (landing), 419 t.(loaded)
Length 158′ 5½”
Beam 23′ 3″
Draft Light 3′ 1½” mean, Landing, 2′ 8″ forward, 4′ 10″ aft, Loaded, 5′ 4″ forward, 5′ 11″ aft
Speed 16 kts (max.), 14 kts maximum continuous
LCI(L) Complement 4 Officers, 24 Enlisted
LCI(G) Complement 5 Officers, 65 Enlisted
LCI(M) Complement 4 Officers, 49 Enlisted
LCI(L) Troop Capacity 6 Officers, 182 Enlisted
LCI(L) Cargo Capacity 75 tons
Armor 2″ plastic splinter protection on gun turrets, conning tower and pilot house
Endurance 4,000 miles at 12 kts, loaded, 500 miles at 15 kts; and 110 tons of fuel
LCI(L) Armament five single 20mm guns, one bow mounted, one each port and starboard forward of wheelhouse, one each port and starboard aft of wheelhouse, on some LCIs two .50 cal machine guns were added
LCI(G) Armament two 40mm guns, four 20mm guns, six .50cal machine guns, 10 MK7 rocket launchers
LCI(M) Armament one single 40mm gun, forward, four 20mm guns, three 4.2mm chemical mortars mounted in three 4ft x 4ft wooden walled 2″ x 6″ high sand boxes on the well deck with the three tripod mortar tubes in position to fire forward over the bow, No. 2 Troop Compartment (under well deck) converted to a magazine
Fuel Capacity 130 tons, lube oil 200 gal.
Propulsion two sets of 4 GM diesels, 4 per shaft, BHP 1,600, twin variable pitch propellers


Technical Diving – How safe is it?

Big Blue Tech explains the safety regarding technical diving.

Koh Tao, Thailand

Deep (100m) heliox bounce diving in the oil industry was briefly fashionable in the 1960’s, before it was realized that upwards of 20% of dives resulted in decompression illness (DCI). Even earlier (the 1920’s) the US made the first helium dives but again, a high incidence of DCI resulted. So what has changed now that many thousands of divers seemingly make safe and uneventful deep technical dives annually? Is it as safe as the technical training agencies purport it to be?

Technical diving as we know it had it’s origins with the cave divers of Florida and Europe. Bill Hamilton, the well known decompression modeler, produced schedules which enabled US cave divers to dive to over 70m using trimix (a mixture of oxygen, helium and nitrogen) and return safely to the surface breathing different “deco” mixes on the way up. This practice forms the basis of all deep technical diving today.

Technical diving, whilst still being a recreation, is clearly different to the hundreds of thousands of recreational SCUBA dives performed for pleasure around the world every year. Technical divers plan to dive beyond what are normally accepted as recreational limits, use gas mixtures other than air, frequently undergo prolonged staged decompression, often dive in an overhead environment (caves, wrecks and under the ice) and employ more sophisticated technology to fulfill their objective (such as closed circuit rebreathers, dive propulsion vehicles and other redundant safety equipment). The nature of the dives they undertake means that self sufficiency and equipment redundancy is crucial, so that in the event of mishap or accident the surface can be reached without assistance from another diver. So although the buddy system is still strongly advocated by most, there is a strong belief in the ability to save ones self in the event a problem arises. In the overhead environment, or when an artificial overhead is in place due to decompression obligation, it is crucial that problems can be sorted out underwater without recourse to an emergency ascent. Such diving requires good understanding of diving and decompression pathophysiology and a sound understanding of dive equipment and the diving environment.

Hence many technical divers appear to be highly motivated, focused and dedicated individuals. The equipment, training and gas costs are not insignificant, so as a group they are older on average than recreational open water divers i.e. many have reached a point in their lives where this type of diving is affordable to them. In this time, they have also gained sufficient diving experience to be comfortable enough in the water. The technical diving community also contains at one end of the spectrum, a small group who are constantly pushing the limits of the sport by diving further into caves, deeper onto wrecks and trying new equipment technologies often modified to meet their specific needs. No one would argue that this group whilst pushing the limits of the sport is certainly incurring significant risk to do so. Like the pioneer cave divers of the ‘70s, deaths in this group are not uncommon, but for those who follow the lessons have been hard learned and make it much safer. Nowadays, the majority of “technical” divers perform countless dives with out incident.

But despite the well trodden path that today’s tech divers follow, despite the high quality of training and equipment available and the almost obsessive nature of many of these divers, just how safe is it compared with standard recreational air diving? Many would suggest that the risks remain too great, because when things go wrong during a technical dive, the surface is just too far away to hope for a good outcome. To try and find a measure of the risk, I have looked to several sources. Various websites delight in naming the ten most dangerous adventure sports. The following are consistently mentioned although the basis for some of the claims is not clear: Base jumping (probably a clear winner!), free diving, cave diving, bull riding, mountain and ice climbing, big-wave surfing, rock fishing, street luging and extreme snow skiing. Activities involving bicycles also rate highly. “Technical” diving per se doesn’t rate a mention. Base jumping sources in the USA suggest from 5-15 participants die per annum in the USA, however the number involved in the sport is not known. In 2002, 24 individuals died whilst rock climbing in the USA. An Austrian source revealed that 1170 people died in the mountains from 1986-1997, giving a risk of 6.7/100 000 participants or 0.007% for rock and ice climbing. Since 1960, over 500 divers have died in caves in Florida, Mexico and the Caribbean which averages out to around 11 deaths per annum, although one would suspect that many more occurred in the early days of the sport before good training and equipment advances were established. As the denominator is not known, a percentage risk cannot be given. In the UK, the overall estimated risk of dying whilst diving is 1:200 000 or 0.0005%. The BSAC have maintained excellent records on diving incidents and fatalities for many years, published each year in the NDC Diving Incidents Reports by Brian Cumming(1). The UK averages 16.3 fatalities per annum, of which a high percentage regularly involve deep diving. This quote from the 2003 report seems representative of most years: “The number of incidents reported in the greater than 50m range is 11 and this is lower than previous years. However 5 of these 11 were fatal incidents, clearly indicating the risks associated with deep diving. There has been a moderation in the number of incidents related to very deep diving, but there is still a clear and very strong correlation between increasing depth and increasing risk. 4 incidents involved depths of greater than 60m and 3 of these were fatalities.” And from 2002: “However the number of incidents reported in the greater than 50m ranges continues to grow. 22 incidents involve dives to greater than 50m and this is the highest number ever recorded in this category. Of these 22, 6 (27%) were fatalities. The message is very clear – Diving at depth brings much greater risk and deep incidents are far more likely to be serious ones”.

More data comes from the 2004 edition of DAN’s “Report on Decompression Illness, Diving Fatalities and Project Dive Exploration” (2), which reports on the year 2002 and some 5 year trends. Project Dive Exploration (PDE) collects data from recreational dives performed with specific types of computers, whether or not the dives result in injury or fatality. Some 70000 dives have been collected since 1995. In this database (2002 only), about 3% of the divers held a technical diving qualification. 2% of dives were performed with trimix or heliox. The exact number of technical dives performed is not known, but may be inferred to be around the 2-3% mark. Overall, 9-10% of divers dying were making technical dives i.e. technical dives are over represented in the fatality figures. I would emphasise that because of the lack of a denominator, these significance of these figures remains unclear.

The final area of interest is that of closed circuit rebreathers (CCRs). CCRs are complex pieces of equipment which demand great diligence, discipline and respect to dive safely. They are enabling tech divers to push back the boundaries of exploration even further, and allow the “average” tech diver to perform dives that were previously too complex or difficult. The most widely used electronic CCR in use is the Inspiration made by Ambient Pressure Diving which was released in 1999. Because it was the first readily available CCR and because of its huge popularity (estimated around 6000 units now worldwide), it has also been involved in the largest number of accidents and fatalities (23 according to one source (3), but possibly more). The unit itself is highly regarded by most in the technical diving community and is CE approved, however by virtue of the number in the marketplace; it has been involved in the most incidents. Should another of the popular CCRs be the market leader, it is likely they would be in the same unenviable position. The 23 fatalities from some 6000 units give a risk of 0.4% or 1 in 240 per owner. Compare this with the 0.007% for Austrian Rock climbers or 0.0005% from UK divers overall.

So what factors may make rebreather diving so dangerous? Closed circuit rebreathers (compared to semi closed rebreathers which are generally not used for deep diving excursions) represent fairly new technology in recreational diving. Breathing gas is recycled around a loop so that exhaled oxygen is available for reuse, so only oxygen required for metabolism is consumed. Carbon dioxide is removed by a soda lime scrubber and metabolized oxygen is replenished into the loop by mechanical, electronic or manual means. A diluent gas is required to maintain volume in the loop on descent, and expanding gas is vented during ascent. All very simple in principle. However the control over the crucial levels of the 2 important gases in the loop (oxygen and carbon dioxide) must be precise or the diver courts disaster. If the partial pressure of oxygen (PO2) stays consistently above 1.4, the risk of convulsion and drowning increases. If the PO2 in the loop falls to hypoxic levels, unheralded unconsciousness (and drowning) may result. Exhaustion of soda lime or a problem with gas flow through the scrubber will cause a disabling rise in carbon dioxide levels. Any loss of integrity of the unit may cause flooding which will render the unit completely unusable (a situation far less likely to occur on SCUBA). Without meticulous pre-dive checks and adherence to procedure, these life threatening occurrences may occur in any CCR unit. Hence the primary safety feature of all rebreathers, is the comprehensive checking of the equipment before a dive. Most fatalities arise because of a problem in checking or maintenance, rather than some inherent fault of the unit.

All of us accept risks on a daily basis. Every year many more than 100 000 people are killed by snakes(4), 960 by crocodiles, 14 by ostriches and 7 by sharks(5). Compare the paranoia about shark attack with the worry over ostriches! Keep it in perspective in other words! However, the (scanty) facts available at present do suggest that technical diving whether deep, wreck, cave or rebreather diving, does have an increased risk of death compared to recreational open water diving. This kind of diving is not for everyone, and to do it safely requires a large investment in time, training, personal fitness and attention to detail. In its present form, it should not become an inevitable progression of advanced open water training following a basic OW course. Certain individuals should never take up technical diving, and most will never wish to. Training agencies must continue to make potential tech divers aware of the risks and maintain standards to the highest level, to avoid the growing tendency for outsiders to over-regulate the sport. Dive shops should be clear at the outset that enrollment into technical dive training will not guarantee successful completion if a high standard is not met.

For the record, I am a passionate cave and rebreather diver. The acceptance of risk is a very personal decision, and for me I cannot imagine a life without diving. But, like all prospective tech divers should do, I have attempted to fully inform myself of the dangers in order to dive safely.

(1) Cumming B. NDC Diving Incident Reports. BSAC website

(2) DAN Report on Decompression Illness, Diving Fatalities and Project Dive Exploration: 2004 edition (Based on 2002 data). Divers Alert Network. ISBN 0-967 3066-5-5

(3) Personal communication, Stephen Hawkins. See

(4) Chippaux J-P. Snake-bites: appraisal of the global situation. Bull WHO 1998; 76(5):515-24.

(5) Stark, P. (2001). Last breath: Cautionary tales from the limits of human endurance. Ballantine.

Wreck Diving Day on Koh Tao Island

Technical and recreational divers explore a ocean wreck in Thailand

Koh Tao, Thailand

Big Blue Tech took eager divers out to the “Big Blue Wreck” today off the coast of Koh Tao Island in the gulf of thailand.

The “Big Blue Wreck” is a wooden passenger ferry that went down without casualty in 45m of water in April of 2009 due to rough weather. Big Blue Tech conducted several searches for the wreck and found her in February of 2010. You can read more about the discovery here: Technical divers discover shipwreck off coast of Thailand

Today’s diving trip was organized to train our divemaster interns on deep, wreck and nitrox skills which started the day previously on a coral dive site and progressed to our deep wreck this morning. The course was conducted by Technical Diving Instructor Helen Artal and assisted by Mark Slinn who is helping out at Big Blue Tech this month as the main staff are in Europe.

On arrival at the wreck site, using GPS to located the wreck a “shot line” or weighted line was dropped as a visual aid for Mark who is a Trimix Diver to descend and secure a fixed line on the wreck for the rest of the divers to use. The shot line was dropped directly on the wreck which goes to show the accuracy and professionalism of the team. After mark secured the line the divers descended and enjoyed 2 dives on the wreck.

This wreck is private and only Big Blue Tech have access to it’s location. This is also in response to environmental research being conducted on the site to the effect of deep coral development and sustainability of wooden wrecks in the region. By keeping the site exclusive it allows for tracking of diver impact on the fragile ecosystem.

Big Blue Tech run frequent wreck day trips throughout the year to several different wrecks along the coast of Koh Tao.

Rebreather Diving in Thailand

Technical Diving school adds the worlds most popular closed circuit rebreather to its collection.

Koh Tao, Thailand

Big Blue Tech recently aquired a new rebreather to it’s collection to provide support to it’s european customers and training opportunities through the BSAC and TDI system of education.

The rebreather is a the AP Inspiration Classic which has sold more units than any other closed circuit rebreather in the world. The Inspiration Classic was the first production rebreather and conctinues to win awards from many diving agencies and magazines.

This also allows Big Blue Tech to provide three models for training of rebreathers with the Drager Dolphin and ISC Megaladon and now Inspiration Classic as options.

With 3 litre cylinders, easy maintenance and simple preparation – the Inspiration brought the benefits of optimal gas consumption and gas mix at all depths to the forefront of diving.

Quickly becoming the choice of expedition divers, film makers and sports divers alike, ranging from beach diving to RIB diving. right up to 100m expedition dives.

To achieve CE certification; the first (and only) CCR to feature dual independent oxygen controllers (Patented), the CCR to set the standard in PO2 control accuracy and scrubber duration; the first to achieve minimal breathing resistance in all diver positions and attitudes, the first mass produced and affordable CCR on the market.

The first to achieve worldwide distributorship with all that entails, including the development of the first unit-specific training courses by the major training agencies; and not least, the innumerable individual firsts that have been achieved by the many thousands of INSPIRATION CCR divers in the world today – from the discovery of virgin wrecks to personal depth and exploration records.

Tech Diving Expedition: Mv Sea Chart Shipwreck

Technical complete survey and penetration of shipwreck off the coast of Thailand

Khao Lak, Thailand

Continuing the expedition James Foleher and James Thornton-Allan spent 3 days and 6 technical wreck penetration dives on the Mv Sea Chart 1 Wreck wreck located close of the famous Similan Islands off Tab Lamu pier south of Khao Lak.

The Mv Sea Chart 1 Wreck lies in 45m of salt water on it’s starboard side. The 85m long shipwreck sank from rough seas in August of 2009.

The final days of wreck diving explored the main wheel house structure exploring several floors towards the hull in search of access to the engine room. Running penetration lines through the wreck the access door was found on the forth floor down but the it was lying closed horizontally. If you imagine the wreck is on its side so all the doors are either hanging open or hanging closed.

At the time the divers didn’t have the tools or material to secure the door open and took both divers combined strength to open it in the first place. Looking inside the door was a long ladder leading to an area that had gauges and boilers but with already 100m penetration to the door another 100m would be needed to reach the engine room in the massive wreck.

There was no way to hatch a plan under water and would require lengthy discussion on the surface. Thankfully all dives were on trimix so narcosis was not an issue.

While plans were made to extend the penetration, storms and rough weather prevented the divers from returning to the wreck to execute the plan.

The divers concluded this portion of the expedition and departed to Phuket to explore the deep reefs and wrecks in that region.

Special thanks to IQ Dive Shop for providing support with gas fills and longtail boat rides. This is the third time we have relied on IQ Dive Shop for support and they have always exceeded our expectation.

Tech Diving Expedition: Mv Sea Chart 1 Wreck

Technical divers explore shipwreck off the coast of Thailand

Khao Lak, Thailand

Continuing the expedition James Foleher and James Thornton-Allan arrived in Khao Lak to commence technical wreck diving on the Mv Sea Chart 1 Wreck wreck located close of the famous Similan Islands off Tab Lamu pier south of Khao Lak.

The Mv Sea Chart 1 Wreck lies in 45m of salt water on it’s starboard side. The 85m long shipwreck sank from rough seas in August of 2009.

Diving from a wooden “longtail” boat provides quick and easy access to the ship wreck. Arriving at the site which has a permanent government mooring line on it you can see the outline of the wreck from the surface which is typical for the conditions in this region which is typically 30-40 meter visibility.

The divers completed 2 accelerated decompression dives with the first one being a orientation dive followed by a small penetration dive.

The next few days will be focused on penetration of the wreck and exploring further into the structure, rooms and cabins in an attempt to reach the engine room. With skills gathered from technical diving and training in overhead environments both the TDI Advanced Wreck and TDI Cave Diver levels the wreck will proove to be a perfect environment to gain experience.

This will be the third time Big Blue Tech has conducted technical diving on this wreck and it is already evident from the last time that divers have been heavily removing items from the wreck. It is quite common for divers to take souvenirs from wrecks however it take away from future divers a chance to see it undisturbed. Many great wrecks in the world have gone from exciting and interesting to boring metal skeleton shells from divers “recovering” items from wrecks. With that the divers will be following it’s philosophy about wreck diving and will not be removing anything from the dive site.

TDI Extended Range Diver Course Completed

The pinnacle of deep air diving certification achieved in Thailand

Koh Tao, Thailand

Big Blue Tech celebrates the graduation of James Foleher from his TDI Extended Range Diver course which was conducted over three days on two separate wrecks in the on Koh Tao Island in the Gulf of Thailand.

As with many of the courses in the TDI training programme, this Extended Range programme serves to add more knowledge and skills to your diving development and leaves you qualified to take on more challenging and adventurous dives.

The course will reinforce much of what has been looked at on previous TDI programmes, but will go into greater depth, as well as introducing some new concepts/ideas.

This course will provide the training and experience required to competently utilize air for dives up to 55 msw (metres of sea water) that require staged decompression, utilizing nitrox mixtures or oxygen during decompression. The object of the programme is to train divers in the proper techniques, equipment requirements, hazards of deep air diving to this depth.

This certification is the maximum depth rating allowed before moving into mixed gas or trimix diving which James will participate in during the later parts of his technical internship.

Wreck diving in Thailand

Divers discover wreck diving in Thailand during a wreck specialty course

Koh Tao, Thailand

Big Blue Tech celebrates teh recent graduation of 4 new wreck divers who explored 2 different wrecks over 3 days off the island of Koh Tao in Thailand. They successfully completed their Wreck Diver Specialty.

The course, conducted by Tech Instructor Andy Cavell, started on our Big Blue Wreck with 2 introductory dives and finished on a shallower local wreck for reeling and mapping skills

The lure of exploring sunken ships and boats is something most divers can’t resist. This temptation prooved too much for our students who couldn’t get enough of wreck diving and the unique marine life found around them.

The student progress on to their deep diver and nitrox diver course in the coming days.

Technical Wreck Diving in Thailand

Certified TDI technical diver explores Thailand’s wrecks

Koh Tao, Thailand

Big Blue Tech has been providing experience dives to Nick Andrianov, an experienced TDI Trimix Diver who joins us from Hong Kong on a brief holiday and diving trip. Nick has been diving with us all week getting dives in some caves, caverns and most recently on our small wreck in one of the confined bays on Koh Tao.

During his week stay Nick will be exploring all the dive sites Koh Tao has to offer and taking a trip to the Unicorn Wreck on a wreck wednesday trip hosted by a local technical liveaboard.

Nick received one on one leadership from our in house technical divemaster team. This is the first time Nick has dived in Thailand and enjoyed diving without large crowds, which made us wonder how it must be diving where he’s been!

Stepping Into March

One of the busiest months on Koh Tao starts off with a bang.

Koh Tao, Thailand – Big Blue Tech was very busy today with the combined effort of most staff working around the clock with different activites.

Dean Jenkins was out taking the divemaster interns out for a dive on one of our local wrecks and tooks some time out for some diving in tech gear. Ash and Andrew were working together to complete a Search and Recovery Specialty for Felix including search patterns, lift bags, knot tying and scenarios. Helen is teaching advanced level courses and spent most of the day in tech gear and analyzing nitrox.Thomas was out on the rebreather. Duncan and James had the day off so played football on the beach.

This might not seem very hectic but tomorrow is the start of a tech course from beginner to extended range followed by more technical diving leading up to a trip at the end of the month.