Pile barrage
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Pile barrages, among other names, are underwater barricades or barrages used for coastal military defence. They are constructed with piles, vertical poles or stakes driven into the bed of a body of wa
Pile barrage of the Shoeburyness Boom, United Kingdom
Close-up of a pile barrage from the Shoeburyness Boom, United Kingdom
Part of Stockholm's old "city pile wall" on Vädersolstavlan (1535)
The Stockholm pile driver operating on ice, from Olaus Magnus' A Description of the Northern Peoples (1555).
Boom (navigational barrier)
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A boom or a chain is an obstacle strung across a navigable stretch of water to control or block navigation. They are sometimes mixed with pile barrages.
Pile barrage
…driven into the bed of a body of water, extending up to, or above, the water line to block the passage of watercraft. They are sometimes also mixed with floating booms and thereof (compare Shoeburyness Boom). They have been used since prehistory to prevent enemy watercraft from entering waterways or harbors, etc., as…
A boom blocking the River Foyle during the siege of Derry
Crusaders break a chain protecting the harbour (at left) in the siege of Damietta.
Boom towers in Norwich
Remains of the great chain that protected the Golden Horn