Straits and Waterways

To reduce the distance of travel from the east to the west coast of the Americas, the Panama Canal was built in Panama, which separates the Caribbean Seas of the Pacific and the Atlantic Oceans. The Panama Canal is an engineering marvel and is known as one the seven modern wonders. It is 77.1 km long, consists of three sets of lock systems, Lakes

Elevation Depth (m) 0 0.5 1 1.5 2 2.5 Area (%) Challenger’s dee p–

Marianas trench depth (10,994 m)

Mean depth (3,734 m)

Mean height (743 m)

Maximum (Mt. Everest height 8,848 m)

Land and deep sea topography

3 3.5 4 4.5 8,000 6,000 4,000 2,000 Sea level –2,000 –4,000 –6,000 –8,000 –10,000 FIGURE 2.4

Miraflores and Gatun as well as rivers and waterways which join the Atlantic with the Pacific. Travelling through the Panama Canal, each ship is lifted to a height of 26 m and also lowered by the same amount. Until 2014 more than 900,000 ships passed through the canal since it was completed in 1914. The optimum size of vessels that can pass through the canal is 50,000–90,000 deadweight tonnes, which are commonly known as Panamax vessels. The largest vessel that has passed through the canal has a length of 296.57 m and a breadth of 32.31 m. The maximum permissible draught through the canal is 13 m. Vessels of dimensions larger than this cannot go through the canal and must go around Cape Horn. Such vessels are bulk carriers, tankers and containerships of large dimensions. There is a plan to have new, bigger and separate lock systems which will allow large 12,000 TEU carrying container vessels with length 366 m, breadth 49 m and draught 15 m.

A similar human made canal is the Suez Canal, which allows ships travelling between Asia and Europe. The Suez Canal joins the Gulf of Suez with the Mediterranean Sea and between landmasses of the Sinai Peninsula and the Egyptian main landmass. The main canal is 162.25 km long with a 22 km long northern access canal and a 9 km long southern access canal. This is a sea-level canal with no locks. The canal allows ships having a beam up to 77.5 m and a draught of 20 m to pass through it. Normally, ships carrying deadweight up to 240,000 tonnes, known as Suezmax vessels, can pass through the canal. If the canal is closed or ships are bigger, they have to go around the Cape of Good Hope, travelling an extra distance of about 4850 km.

The sea distance between the eastern Asian subcontinent and Australian continent is strewn with islands of various shapes and sizes and the in-between waterways are treach- erous with regard to depth. However, there is a safe waterway for the passage of ships, known as the Malacca Strait, which lies between the Malayan Peninsula and the island of Sumatra. This strait is a natural seaway having a length of about 805 km, joining the Indian and the Pacific Oceans. At its narrowest location, somewhere south of Singapore, it is 2.5 km wide. The depth of the waterway allows ships with draught up to 25 m to pass safely through the strait. The vessels that can pass through this strait are known as Malaccamax vessels. This is one of the busiest straits of the world through which around a quarter of the international oil cargo passes, going from the Middle East to the Far East.

Though not a main waterway, the Bering Strait, which is the waterway between the extreme east of Russia and the extreme west of Alaska, has a width of 85 km with a vary- ing depth between 30 and 49 m. It joins the Chukchi Sea in the Arctic Ocean and the Bering Sea on the south, which is a part of the Pacific Ocean. This is not a main shipping route. However, if a ship negotiates the Bering Strait, it has to be of adequate strength to negotiate ice on its path. Similarly, there are a number of straits and canals across the world which have been used as passages for large ships and small boats, reducing the distances of travel and cost. One such strait is the Palk Strait, which is a strait between Tamil Nadu in India and the Mannar District of the Northern Province of the island nation of Sri Lanka. It connects the Bay of Bengal in the north-east with the Palk Bay and thence with the Gulf of Mannar in the south-west. The strait is 53–80 km wide. It is studded at its southern end with a chain of low islands and reef shoals, which are collectively called Adam’s Bridge. This chain extends between Dhanushkodi on Pamban Island in Tamil Nadu and Mannar Island in Sri Lanka. Because of this, ocean-going vessels do not pass through this strait. Only small passenger and fishing boats negotiate this strait.

The St. Lawrence Seaway, the river way system consisting of a system of locks, canals, channels and the St. Lawrence River, permits ocean-going vessels to travel from the Atlantic Ocean on the east coast of North America to the Great Lakes, as far inland as the western end of Lake Superior on the borders of the United States and Canada. The riverine

section consists of several stretches of navigable channels, a number of locks, as well as canals along the banks of the St. Lawrence River to bypass several rapids and dams along the way. There are 15 locks on the river, lifting the vessels to a height of more than 180 m over the entire stretch of the seaway. The size of vessels which can traverse the seaway is limited by the size of locks. The maximum allowed vessel size is 225.6 m long, 23.8 m wide and 8.1 m draught. Vessels designed for the Great Lakes following the opening of the seaway are informally known as Seawaymax vessels. This is one of the main trade routes of the United States connecting the hinterland to the Atlantic Ocean and carrying bulk, general and grain cargo and further along the American east coast as well to other coun- tries. Figure 2.5 shows the major trade routes of the world. Note the importance of canals discussed earlier (Rodrigue 2013).