Portland harbour

Portland Harbour is located beside the Isle of Portland, off Dorset, on the south coast of England. When completed in 1872, its 520 hectare surface area made it the largest man-made harbour in the world, and it is still the third largest today, after the 4,500 hectare Ras Laffan Harbour in Qatar and the 1,500 hectare Cherbourg Harbour in France. It is naturally protected by Portland to the south, Chesil Beach to the west and mainland Dorset to the north. It consists of four breakwaters — two southern and two northern. These have a total length of 4.57 kilometres and enclose approximately 520 hectares. The initial southern breakwaters were built between 1849–72, and Portland Harbour was a Royal Navy base until 1995.

Historically the original harbour was formed by the protection offered by the south coast of England, Chesil Beach and the Isle of Portland. This gave protection from the weather to ships from all directions except the east. The natural shelter was used by ships for centuries, and Romans valued the area's strategic importance. In the 16th-century, King Henry VIII built Portland Castle and Sandsfoot Castle to defend the anchorage.

A refuge harbour had been suggested in 1794, however parliamentary approval was not granted until 1844. Construction of the modern harbour began in 1845 when the Royal Navy established a base at Portland for replenishment of the fleet. The new base at Portland was to be the first naval anchorage specifically designed for the new steam navy. The construction of the initial two breakwaters - the southern pair - began in 1849, after HRH Prince Albert laid the foundation stone on 25 July 1849. They were designed by engineer James Meadows Rendel, and the work carried out under civil engineer John Towlerton Leather, with Rendel as engineer in chief (until his death in 1856), and John Coode as resident engineer. The two southern breakwaters were declared complete by HRH Edward the Prince of Wales on 10 August 1872. The construction work had become Dorset's greatest tourist attraction, and the country's most expensive public project.

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