Encounters with Atolls and Reefs of the Indian and Southwest Pacific Oceans Review by Geoff Walker To those who have not seen an Atoll, they may ask what it is, well, an Atoll is a circular-shaped coral reef, island, or series of islets, which surrounds a body of water called a lagoon. Sometimes, Atolls and lagoons encompass a central island. Channels between islets connect a lagoon to the open ocean or sea. They are best observed in tropical regions, particularly in the Indian Ocean as well as the central and south west Pacific Ocean. They come in all sizes, some are minute, whilst others are massive in area, thus providing large, safe, protected anchorages. Some are well renowned, whilst others have never been heard of, and are little more than a miniscule notation or “dot” on an Admiralty Chart. There is a tendency for Atolls to form into clusters or groups and they can be a serious hazard to surface navigation. Many have taken their toll on unwary mariners, and which bear the evidence by numerous shipwrecks; a few of which are captured in this account. The formation of an Atoll is a slow process that can take millions of years. It starts when an underwater volcano erupts, creating a buildup of lava on the seafloor. With the passage of time, and continued eruptions, the lava continues to build until it breaks through the ocean's surface and forms an island. With the passage of time, hard corals begin to build a limestone reef around the island. Once the outer reef is formed it is called a “Fringe Reef” and encircles the recently created island, just below the ocean surface. Over millennial cycles, the ocean waves begin to erode the island, causing it to eventually subside and collapse below the surface, leaving a lagoon of water surrounded by a coral reef. This is known as a “Barrier Reef” due to the protective barrier it creates from the ocean and winds. Eventually the ocean breaks up the coral reef into tiny grains of sand which collect on the reef to form a ring or circle of low laying shaped island. The best examples of classic Atolls are seen in the Maldives, Polynesia, and Micronesia. Some of the more famous Atolls, are located in such places as the Maldive Islands, which is situated in the north-central part of the Indian Ocean, and in reality, is little more than a chain of some 26 individual Atolls, and about 1200 small coral islands, running more or less north and south, over a distance of about 510 nautical miles. There are four main navigable channels used by commercial shipping, running east and west between and across the archipelago, namely, the Kardiva Channel, Veimandu Channel, One-and-a-Half Degree Channel, and Equatorial Channel. The northernmost atoll is about 370 miles south- southwest of the Indian mainland, and the central area, including the capital island of Male’, is about 400 miles southwest of Sri Lanka. Some 200 of the islands are inhabited. All the islands are low-lying, none rising to more than about 1.8 meters above sea level. Barrier reefs protect the islands from the destructive effects of monsoons. The rainy season, from May to August, is brought by the southwest monsoon; from December to March the northeast monsoon brings dry and mild winds. The Maldive Islands are renowned for their wide range of mega resorts, in particular, to those attracted to aquatic sports, scuba diving and deep-sea fishing. The cargo ship “Laganbank” built 1930, sailed from Calcutta with a cargo of Jute, Gunnies, Shellac and Tea, bound for Rio de Janeiro via Colombo, where she arrived on 6th January 1938, to load additional cargo of Rubber. All went well during this part of the voyage. The Master had intended to transit the One-and-a-Half Degree Channel, on the sector of the voyage to the Cape of Good Hope, but the vessel was hampered by weather and the Master was unable to take astronomical observations, causing him to rely solely on Dead Reckoning. The vessel stranded at 4.47 a.m. on the morning of the 13th January 1938 on the islet of Isdu, at the north-east corner of Haddummati Atoll in 2.6 N. 73.35 E of the Maldive Islands, and was abandoned as a total loss. All crew were rescued by “Tweedbank”. The Board of Trade court of Enquiry found that the Master had been negligent and had taken inadequate safety precautions with insufficient allowances made to counter a strong north-westerly current. His Master’s Certificate was suspended for a period of 12 months. An interesting image of the 1930 built “Laganbank” seen in happier times. (Unknown photographer) The Chagos Archipelago is another Indian Ocean group of Atolls and Islands situated in the central Indian Ocean, located about 1,000 miles south of the southern tip of the Indian subcontinent. It falls within the British Indian Ocean Territory. The islands, which were uninhabited when they were discovered by Portuguese explorers in the 16th century, were situated on the main international trade routes and became the focus of competing claims by European powers. In the late 18th century France took possession of the Chagos Archipelago and Seychelles as dependencies of Mauritius, and coconut plantations were established to produce copra. Slaves were imported from Africa to work the plantations. In the early 19th Century, the British repossessed the islands. The Chagos Archipelago are a group of seven atolls comprising more than 60 individual tropical islands in the Indian Ocean about 310 miles south of the Maldives archipelago. In 1965 The United Kingdom and the United States decided to establish military bases in the British Indian Ocean Territory for the purpose of establishing defense and communications facilities. The new territory comprised the Aldabra Islands and the Farquhar and Desroches islands, formerly part of the Seychelles Colony, along with the Chagos Archipelago, formerly part of the Mauritius Colony. A major British-U.S. military facility was built on Diego Garcia in 1971, and the plantations there were closed. Between 1967 and 1973, Britain removed the Ilois, or Chagossians—inhabitants of the Chagos Archipelago, descended from African slaves and Indian plantation workers. They were given the choice of resettlement in either the Seychelles or Mauritius, which became independent in 1968; the majority chose the latter with a smaller number of Ilois resettling in the United Kingdom. In 1976 the islands obtained from Seychelles were returned when that Colony became independent. Thereafter the British Indian Ocean Territory (BIOT) in the region comprised only the islands of the Chagos Archipelago with a military base on Diego Garcia, the largest of the Chagos Islands. Since 1971, only the atoll of Diego Garcia remains inhabited, and only by military and civilian contracted personnel. There have been numerous international court cases as well as a Committee of Review in the House of Lords, as to the legalities of the United Kingdom evicting the original inhabitants of the Islands. However, the military establishment remains and as of August 2018, Diego Garcia is the only inhabited island of the BIOT. Diego Garcia is the largest land mass in the Chagos Archipelago (which includes Peros Banhos, the Salomon Islands, the Three Brothers, the Egmont Islands, and the Great Chagos Bank), being an Atoll occupying approximately 67 sq miles, of which 10 sq miles is dry land. The continuous portion of the Atoll rim stretches 40 miles from one end to the other, enclosing a lagoon 13 miles long, and up to 7 miles wide, with a 4 mile-wide, entrance at the northern end. Three small islands are located within the entrance. Map and aerial view show of the largest Atoll in the Chagos Archipelago, Diego Garcia. The island consists of the largest continuous dryland rim of all Atolls in the world Situated about 1700 miles northwest of Perth, Western Australia, and 560 miles from Christmas Island, the Cocos Islands, also known as the Keeling Islands, are a group of coral islands that form two Atolls. Only two of the 27 islands are inhabited with the remainder unexplored. The Territory of Cocos (Keeling) Islands is an Australian external territory in the Indian Ocean, comprising a small archipelago approximately midway between Australia and Sri Lanka, and relatively close to the Indonesian island of Sumatra, and is therefore part of Southeast Asia. The territory consists of two Atolls made up of 27 coral islands, of which only two – West Island and Home Island – are inhabited. The population of around 600 people consists mainly of ethnic Cocos Malays. The Cocos Islands, together with Christmas Island, which is about 600 miles to the east, forms the Australian Indian Ocean Territories administrative group. The islands were discovered in 1609 by William Keeling, but no settlement occurred until the early 19th century. One of the first settlers was John Clunies-Ross, a Scottish merchant; much of the island's current population is descended from the Malay workers he brought in to work his copra plantation. This resulted in the Clunies-Ross family ruling the islands as a private fiefdom for almost 150 years, with the head of the family usually recognized as resident magistrate. The British annexed the islands in 1857, and for the next century they were administered from either Ceylon or Singapore. The territory was transferred to Australia in 1955, although until 1979, virtually all, of the island's real estate still belonged to the Clunies-Ross family, and for many years, the islands were a powerhouse of copra production. Apart from disruptions caused by cyclone damage, the industry only ceased in 1987 but the abundant coconut palms throughout the Cocos still bear testament to the extent of the copra trade.