Monday, March 07, 2011

Moving around on the ocean floor

Deep sea Navy divers based at Kochi recently set a national record when they went to a depth of 233m. A look at their lives and the risks and dangers of their profession

Photos: A National record-setting team. (From left)M.K. Prusty, Kamlesh Kumar Singh and Shrirom Singh, Abhijeet Sangle, and Narender Kumar; divers on the ocean floor

By Shevlin Sebastian

“It’s so great to be outside,” says deep sea diver Lieutenant Commander Abhijeet Sangle, as he stands on the deck of the INS Nireekshak. He looks upwards and says, “The sky looks beautiful.”

The sky is, indeed, a translucent blue. A gentle breeze is blowing, while grey-feathered pigeons fly about lazily on this sunny February morning.

Sangle has just stepped out after spending 11 days in a decompression chamber in the ship, which is docked at the Southern Naval Command base at Willingdon island, Kochi. The chamber is a narrow structure, with beds on either side, and a chair and a TV set at one corner.

There are four other crew members: chief petty officers Kamlesh Kumar Singh and Shrirom Singh, and leading seamen, M.K. Prusty and Narender Kumar. Among them, Abhishek, Kamlesh and Shrirom went to a depth of 233 metres, 70 kilometres off the coast ofKerala. “This is a new national record,” says Commanding Officer A.N. Golaya.

The earlier record of 217 metres was also set by members of the Nireekshak in March, 2007. After the previous record was set, the divers made a plaque commemorating the event. “At the bottom, they wrote, ‘We can do it again’”, says Golaya. “And they have kept their word.”

Deep sea or saturation diving is a complex and dangerous profession. “For every 10 metres that a diver goes down, the pressure increases by one atmosphere,” says Golaya. The pressure on the surface is one atmosphere. At 200 metres, a diver faces 21 times the pressure that is there on land. So, there are many steps to take before a diver descends to the ocean bed (see box).

But clearly, there are some unusual reactions that occur when one goes down. At a deeper level, you cannot breathe nitrogen. Normal air has 21% oxygen and 79% nitrogen. “Nitrogen becomes a narcotic in the depths of the sea,” says Golaya. “A person experiences the same symptoms as one who is drunk. So, we substitute nitrogen with helium. It is a mixture of helium and oxygen – heliox – which is given.”

Your voice also gets affected. “The vocal chords are designed for air,” says Golaya. “When you are in a compressed environment, and breathing helium, you experience the Donald Duck effect. The voice comes out as an odd twang and, actually, it takes some time to understand what the divers are saying.”

Saturation diving is needed for various jobs. “The oil industry would never have been possible if there had been no saturation diving,” says Commander Sharma. “The laying of the underwater pipelines, the repair, the welding and the cutting are done by civilian divers.” Meanwhile, the Navy divers save sailors who are trapped in submarines, do salvage operations, and retrieve material from sunken ships.

In 2003, responding to a request from the Archaeological Survey of India, the Navy divers salvaged coins and a cannon from a Portuguese ship, 'Princess Royal', which sank off the Lakshadweep islands two hundred years ago.

To do these jobs you have to be endowed with a particular kind of character. Nearly all of them have a love for adventure. “They like to test the limits,” says Golaya. “The divers are usually calm and have a lot of self-confidence. They have a high degree of team spirit, because a diver's life depends on others. If a diver goes down, and somebody on the ship adjusts the oxygen pressure wrongly, he could die.”

A diver has to be physically strong. The helmet itself weights 17 kgs. The current is at one and a half knots or 3 kms per hour. “When you are on the ocean floor, movement becomes very difficult,” says Sharma. “So you have to be physically fit. You would also need to have mental toughness because you have to spend long hours in a claustrophobic environment.”

But for the divers, it does not seem to be an issue. Says seaman M.K. Prusty, “I love every moment that I am on the ocean bed. It is one of the most magical experiences ever.”

The ABC of diving

Divers have to be pressurised to the required depth in the Deck Decompression Chamber (DDC) aboard the ship. This could take several hours, depending on the depth to which they intend to dive.

A diving capsule or a 'bell' is connected to the DDC and the interior of the capsule is pressurised to the same pressure to which the divers have already been subjected to.

The divers enter the bell, and they are lowered into the water. They wear a thick suit, a helmet and goggles, with lights fitted on them, and carry two tanks on their back. If they are going to a depth of 220 metres, there will be an eight-hour stop at 120m, so that they can get used to the pressure.

When they reach the desired depth, one or two divers will step out of the capsule and do the work that they have been assigned. They are attached to an umbilical cord which provides breathing gas, communications, and hot water that goes around their suits to keep them warm.

When the work is over, they enter the capsule, and the team is lifted up to the ship. Then they enter the decompression chamber, which is at the same pressure as the bell.

The divers spent around 10 days in the DDC as the pressure is slowly brought on par with the atmospheric pressure. In those ten days, they watch TV, read, and listen to lectures. Food, books and CDs are provided through a hatch. A water closet is also attached to the DDC.

‘A place of exceptional beauty’

Lieutenant Commander Abhijeet Sangle has completed about 15 dives so far. But, of course, the most memorable dive was the one in which he set the national record at 233 m on February 7.

“It is an area where few men have ventured before,” he says. “The ocean bed is a place of exceptional beauty. All I can see is this deep blue colour all around me. I am unable to define the blue. It is such a magical colour. I have not seen it anywhere else. I cannot take a crayon and recreate it on a piece of paper. I also have no words to describe it.”

As Sangle talks, he is staring into the distance, his mind far away. “I have to admit that I prefer to be on the ocean floor than on land,” he says, with a smile.

On an average two dives take place every month. And divers get their turns by rotation. “I have dived in many places in the Arabian Sea, as well as the Bay of Bengal,” says Sangle. “It is important to dive regularly. It is like your motorbike. If you don't use your bike for a long time, it will get rusty. So we have to keep diving in order to remain fresh and alert. We also learn how to act during an emergency. Which valves to operate? What are the oxygen levels? It is for our safety and well-being.”

(The New Indian Express, Chennai)

No comments:

Post a Comment