Alpha - 521: Exploring the deep sea | Sunday Observer

Alpha - 521: Exploring the deep sea

Alpha 521
Alpha 521

The ocean is full of undiscovered areas, shrouded in mystery. Her depths reveal surprising historical artifacts and bountiful natural treasures. The Sri Lanka Navy is now operating her first dedicated diving vessel named Alpha- 521.

This vessel with deep sea endurance was gifted from France in March 2005, when she was a merchant vessel. Subsequently, outfitted as per naval patrolling requirements she is now transformed into a deep sea diving platform. She made a successful salvage of a ten ton propeller, which had once belonged to a merchant ship during the Second World War.

I boarded the vessel in Colombo, and was greeted by the Quarter Master. The visual image of the ship was very different from the other combat off shore patrol vessels I had previously visited. A blue and white canvas canopy suspended between two posts shielded the crew from the sun. The executive officer, Lieutenant Commander G.W.N.P. Kumara explained, “This vessel is unique as she is the launching platform for our divers. Usually, there are divers attached to shore units. Now with this vessel we can sail into the deep sea and take part in adventurous diving operations. Alpha 521 has a displacement of 592 tons with a sailing speed of 10 knots. Her sea endurance is almost 12 days. We have a crew of 81 men including 9 officers.”

We walked into the wheel house on level four, where radars and echo sounders were in operation. From here the ocean was a magnificent sight. The vessel is 54 metres long and 11 metres wide, commanded by Cdr. T.I.P. Fernando.

The navy divers have a long history but their services have been silent, in the realms of the sea. Diving officers and sailors operate in two certified categories – CDO, i.e. Clearance Diving Officer who has the capacity to descend up to 55 metres underwater and SDO, i.e. Ship Diving Officer who can only venture 30 metres underwater. The present Navy Commander Vice Admiral Piyal de Silva is a pioneer CDO operative in the country. The navy diver training school is established in Trincomalee.

Lieutenant Dilshan Jayasekera, a CDO attached to Alpha-521 explained, “A Navy diver has an important task on entering the deep sea. Each natural domain has its own risks. In addition there are threats from dangerous marine creatures such as the jelly fish and sharks. Divers could get entangled in fishing nets and ropes. Before a diving expedition there is an investigation team that launches from this vessel by boat to examine the designated sea area. We calculate the depth at which the diver would have to descend. The assigned officer or sailor has his meal six hours before the dive. He must be fully alert.

We always send our men in pairs with another diver suited to him and kept standby for an emergency. Before the diver enters the water we hoist the Alpha flag on the ship’s mast- it is an international flag symbol indicating the presence of a diver underwater and warns other ships to keep clear at slow speed”.

A few of the men recollected their experience of the first major salvage diving expedition that took place 2 nautical miles off the Little Basses area. A Sub- Lieutenant SDO explained, “Prior to this expedition our Officer in Charge made the first visit by small boat, our target was to locate and drag a 10 ton propeller from the sea bed. The entire ship’s crew was excited and busy that morning. Ropes and cables were positioned. We had planned to lift the massive propeller using a system of air bags. We have air bags that can lift and float – with a capacity of 1 ton, 3 tons, 5 tons and 10 tons. In this operation we used two of the 3 ton airbags and one 5 ton air bag. When the cables were attached the anticipation of all on the ship were at their peak. Shortly, the shape of the propeller was visible close to the waterline. We managed to tow the heavy propeller to the port of Hambantota and subsequently brought this historic relic to SLNS Rangalla in Colombo where it was hoisted by crane”.

We walked to the rear of the ship and saw the ramp from which divers enter the water. In addition, there is another side hatch opening into the sea from which divers can venture into the ocean.

One of the divers was engaged in a routine inspection in his rubberized diving uniform. The temperature of the sea water is a vital element that impacts diving capability. Along with the fins, face mask, buoyancy device and two oxygen tanks he enters the water with a weight of 16 kilograms. The tanks provide him with air for almost 30 minutes. Divers must focus on how long they have been underwater and ascend carefully back to the ship. Normally, the ascent rate is 10 metres per minute for divers operating deeper than 20 feet. Ascent rates must be monitored to prevent the supersaturation of tissues which causes bubbles to build up. There is always a risk of decompression sickness which if not treated rapidly can make one paralyzed or even be fatal. The Navy has its specialized recompression treatment chamber at the Eastern Naval Command, Trincomalee.

Alpha -521 maintains her own security at sea, as she is fitted with guns and anti aircraft armament. We walked below the deck to see the crew quarters. The ship’s galley (kitchen) was a busy area as cooks chopped vegetables and a large cauldron of rice was already boiling. The sailors were engaged in their daily sea routine. This auxiliary vessel is powered by a Duwant turbine that generates 2,000 horse power. She has two anchors weighing 450 Kg each. When not engaged in deep sea dives the captain and crew engage in naval patrols. I joined the crew for a spicy meal and understood the camaraderie that binds these men on their adventure laden expeditions into the ocean.

There are many historic shipwreck sites in Sri Lanka, including that of HMS Hermes which sank during the Second World War. Alpha-521 has many expeditions ahead. 

Comments