Sea lane

Asea lane,sea roadorshipping laneis a regularly usednavigableroute for largewater vessels(ships) on widewaterwayssuch asoceansand largelakes,and is preferably safe, direct and economic. During theAge of Sail,they were determined by the distribution ofland massesbut also by theprevailing winds,whose discovery was crucial for the success of long maritime voyages. Sea lanes are very important for seaborne trade.

History

The westerlies and trade winds

The ocean currents

Main article:Wind § Global climatology

The establishment of theNorth Atlanticsea lanes was inspired by thesinkingof the USmailsteamerSSArcticbycollisionwith the French steamerSSVestain October 1854 which resulted in the loss of over 300 lives. Lieutenant M. F. Maury of the US Navy first published a section titled "Steam Lanes Across the Atlantic" in his 1855Sailing Directionsproposing sea lanes along the 42 degreelatitude.A number of international conferences and committees were held in 1866, 1872, 1887, 1889, and 1891 all of which left the designation of sea lanes to the principal trans-Atlantic steamship companies at the time;Cunard,White Star,Inman,National Line,andGuion Lines.In 1913–1914 theInternational Convention for Safety of Life at Seaheld inLondonagain reaffirmed that the selection of routes across the Atlantic in both directions is left to the responsibility of the steamship companies.

Shipping lanes came to be by analysing the prevailing winds. The trade winds allowed ships to sail towards the west quickly, and the westerlies allowed ships to travel to the east quickly. As such, the sea lanes are mostly chosen to take full advantage of these winds. Currents are also similarly followed as well, which also gives an advantage to the vessel.Some routes, such as that fromCape TowntoRio de Janeiro(passingTristan da Cunha), were not able to take advantage of these natural factors.

Main sea lanes may also attractpirates.Pax Britannicawas the period from 1815–1914 during which the BritishRoyal Navycontrolled most of the key maritime trade routes, and also suppressed piracy and the slave trade. DuringWorld War I,as GermanU-boatsbegan hittingAmericanandBritishshipping,theAlliedtrade vessels began to move out of the usual sea lanes to be escorted bynaval ships.

Advantages

Behind thecardinal markis a sea lane opened on an ice-covered sea.

Although most ships no longer use sails (having switched them for engines), the wind still creates waves, and this can causeheeling.As such following the overall direction of the trade winds and westerlies is still very useful. However, it is best for any vessel that is not engaged in trading, or is smaller than a certain length, to avoid the lanes. This is not only because the slight chance of a collision with a large ship that can easily cause a smaller ship to sink, but also because large vessels are much less maneuverable than smaller ships, and need much more depth. Smaller ships can thus easily take courses that are nearer to the shore. Unlike with road traffic, there is no exact "road" a ship must follow, so this can easily be done.

Shipping lanes are the busiest parts of the sea, thus being a useful place for stranded boaters whose boats are sinking or people on a liferaft to boat to, and be rescued by a passing ship.

Threats from shipping lanes

Left: This map of shipping routes illustrates the present-day density of commercial shipping in the world's oceans. Right: 16th century and current day trade routes prey to pirating and privateering.

Shipping lanes may pose threats to some ocean-going craft. Small boats risk conflicts with bigger ships if they follow the shipping lanes. Sections of lanes exist which can be shallow or have some kind of obstruction (such assand banks). This threat is greatest when passing some narrows, such as between islands in the Indian Ocean (e.g. inIndonesia) as well as between islands in the Pacific (e.g. near the Marquesas islands, Tahiti). Some shipping lanes, such as theStraits of Malaccaoff Indonesia andMalaysia,and the waters offSomalia,are frequented bypiratesoperating independently or asprivateers(for companies and countries). Passing ships run the risk of being attacked and held for ransom.

Busiest shipping lanes

The world's busiest shipping lane is theDover Strait.500–600 vessels per day traverse the narrow strait and in 1999 1.4 billion tonnes gross, carried by 62,500 vessels passed through the strait.

See also

• Sea lines of communication
• Roadstead
• Trade route