Boom (navigational barrier)

Boom (navigational barrier)

A boom is a special barrier placed across water to stop ships and boats from passing through. Sometimes called a chain, these barriers can be made from many different materials and are often made stronger by mixing them with pile barrages.

Today, booms are mostly used to keep people out of dangerous areas. In the past, they were also used in wars to stop enemy ships. For example, a modern boom can act like an anti-submarine net to protect important places.

Besides safety and war, booms have also been used to make ships stop and pay a toll before they could continue their journey. This helped people in charge collect money from passing ships.

Description

A boom is something that floats on the water to block or control movement. Sometimes, a chain is used instead, and it can be placed on the surface or below the water. This chain can be made to float by using rafts, logs, ships, or other wooden materials, turning it into a boom as well.

Historical uses

In medieval times, a chain or boom could be attached to a special chain tower or boom tower. These towers were strong and helped protect the chain. By lifting or lowering the chain, people could decide who was allowed to pass through the water.

Sometimes, big ships could break through these chains. This happened during the siege of Damietta, the raid on the Medway, and the Battle of Vigo Bay. Attackers would also capture the towers and cut the chains with tools. For example, during the siege of Derry, sailors in a small boat cut the boom there.

Because these booms were important for protection, they were often guarded by soldiers. This could include towers on land, artillery positions, or forts. In the Age of Sail, ships with big cannons could help protect the boom by firing their broadsides at anyone trying to break through. Sometimes, several booms would be placed across the same stretch of water for extra safety.

Examples

Historical

• The entrance to the Cothon at Carthage had a chain for protection.
• A chain guarded Portsmouth Harbour from 1431 to 1539 at Fort Blockhouse.
• The Leonine Wall used a chain to block the Tiber.
• A chain stretched across the Golden Horn.
• A chain and boom stopped ships on the River Medway during the Raid on the Medway.
• The Hudson River Chain was used as a barrier.
• The Parana River had a chain during the Battle of Vuelta de Obligado.
• During the American Civil War, a chain was put across the Mississippi River from Columbus, Kentucky to Missouri to stop Union ships.
• A chain was placed between the A Palma Castle in Mugardos and Saint Philip Castle in the ria of Ferrol to protect the city and naval base.