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Boom (navigational barrier)

technology Maturity 11-13 Next article →

A boom is a barrier on water.

Siege of Londonderry boom detail
Siege of Londonderry boom detail

It stops or controls boats. A boom usually floats on the surface. A chain can float or stay below the water. Sometimes people attach a chain to logs or rafts. This makes the chain act like a boom.

Castillosferrol
Castillosferrol

People use booms for many things. Today, they can keep boats away from danger. In the past, they were used for war. They kept enemy ships out of ports. Some booms made ships pay a toll to pass.

In old times, a chain might connect to a tower. This tower is called a boom tower. It helped people raise or lower the chain. They used a machine called a windlass to move it. This let ships pass through when it was safe.

Booms were often well guarded. Some had forts or big guns nearby. A very large ship might break a boom. Other times, sailors would cut the boom. This happened during the siege of Derry. Sailors used a longboat to reach the boom. They cut it so they could pass.

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File:Siege of Londonderry boom detail.jpg
Siege of Londonderry boom detail.jpg
File:Castillosferrol.PNG
Castillosferrol.PNG
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