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The Vertical Wreck, Koho Maru-5 or PAK 1 used to be sitting vertical because of huge gas tanks at one side of the wreck keeping it floating.

Name Dive Site:Vertical Wreck
Depth: 5-40m (16-131ft)
Visibility: 10-20m (32-65ft)
Accessibility: Boat, Live-aboard
Inserted/Added by: lars, © Author: Lars Hemel

Rated 5.0, 1 votes

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The Pak 1, Koho Maru-5 or Vertical Wreck is one of the most unique wrecks in the world situated just south of Pattaya. It is a shipwreck which has been sitting in a vertical position for more than six years. Nowadays she is levelled into a horizontally position at a depth of 42 meters and is mainly visited by technical divers using oxygen, nitrox or trimix. The unique vertical feature of the wreck is gone and what remains is diving on a historic wreck with some excellent explorations of all the holds. The wreck's bow starts being visible below twenty meters deep and experiences a cold thermo cline at thirty meters of depth, often dropping visibilities to less than five meters. The place where the two gas tanks had been sitting is now empty but can still be accessed. Be careful not to kick up too much silt too keep it safe for yourselves and others. There are many cables, ropes and fishing lines that cover the wreck and make it easy to get entangled into. At the stern you will find the bridge and cabin areas with its aft crew area still beautifully painted in white. Experienced wreck trained divers can enter the bridge area, engine room and crew quarters.

How could a ship sink and remain at a steady vertical position for over six years? The ship named Koho Maru V was made in Japan used for transporting gas (LPG) around the world. She serviced many different cities but when she was sold to a Thai company her final years had begun. She was renamed PAK 1 and sank after just a few years of service, fifty kilometers west of Koh Chang during a huge storm on 25th of August 1996. Only two of the twelve crewmen survived the accident. The remains of the first ten crew members were never found lost in the ocean.

The word spread quickly and within weeks there were fishermen and dive tours checking out the wreck which was situated perfectly vertical in clear waters and had a depth range between five and sixty meters deep. It was going to be one of Thailand's best wreck dives suitable for novice, experienced and technical divers. Inside the wreck there were huge tanks filled with LPG who kept the wreck vertical but didn't cause for enough buoyancy to re-float it completely. Gas is slightly less dense than water which was believed to keep the wreck from sinking. From its first moments on there were small leaks of gas, but in such a speed that the wreck was believed to stay into this position for decades. In December 2001 there was an eruption of a huge bubble of gas creating an unhealthy smell on the surface. Later in February 2002 divers were treated with penetration possibilities of submerged area's that had previously been in the mud. Because of the leaking gas the wreck had started to re-float in stead of sinking what all experts believed was going to happen.

It didn't took long before several parts of the wreck had reached the surface and the wreck started floating because of the wind and currents towards Cambodia right into a heavy shipping lane of oil tankers. The wreck was still loaded with gas which could lead to heavy explosions when she collided with other ships. The vessel's insurers didn't take any action so it was the Thai navy who decided the wreck had to be sunk and towed it to its planned resting place 150 km away from its previous location. A first set of detonators didn't work, a second set detonated the charges and created a heavy explosion. The explosion had ruptured one of the gas tanks which led to an extremely heavy smell of leaking gas. Boats had to retreat for more than fifteen kilometers because of safety measures. Now the wreck was even lighter and rose thirty meters above sea level. It is not exact clear how the wreck was finally brought to the ocean floor but she arrived there. Once again it only took days before dive operators checked out this new location of a once o so spectacular and unique wreck. It is the history that should attract you for this wreck dive. Otherwise there are better dive sites in the area.

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