What Are Dry Docks? Different Types of Dry Docks

Regular docks are probably familiar to you already. There are numerous shapes and sizes to choose from, and they can be used right next to land to stop boats of all sizes. These devices would make entering and exiting a ship or transporting cargo difficult. A dock also prevents vessels from moving in the water, preventing them from getting swept away or damaged if they run into other objects.

Dry docks are a more specialized type of dock. Depending on the context, the term dry dock may refer to both a process and a structure. The drydocking process involves removing a ship from the water and transferring it to land. These physical assemblies are also known as dry docks. Docks allow people to bring sea vessels onto land, contrary to regular docks, where boats remain afloat. 

What are dry docks?

The main component of dry docks is the moving parts which allow vessels to move onto dry land. Other methods involve pumping water away from the boats, while others require pulling the ship to the shore.

Each dry dock has a platform that helps keep ships from tipping over once they are out of the water. Furthermore, most dry docks have walls on the left and right sides used to enclose and access the boats they hold. In the water, the height of the wall is approximately the same as a regular dock.

The purpose of dry docks

If you have learned what dry docks are, you might be wondering why people build them. Even though dry docks often require more complex designs than standard docks, they are quite popular. This is because dry docks serve a unique purpose. Water-based vessels require routine maintenance, just like land vehicles and aircraft.

Under normal circumstances, one can access the interior compartments, components, and boat sections above the water. It is, however, arduous to work with the portion of the ship underwater, since people would have to remain in the water.

Types of dry docks

  1. Graving Dry Dock

An on-land dry dock of this type usually has solid concrete blocks, walls, and gates with a rectangular construction near the coastal waters. The vessel rests on blocks inside a dry dock. Once the ship is in an appropriate position, the gate is closed, and the water is drained with the help of an industrial valve.

In the past, stone and timber were used to construct graveyard dry docks. The enclosure is made of steel and concrete nowadays. Once a ship is on the blocks, a heavy steel gate is used to seal the dock to prevent water from entering the enclosure.

Depending on the gate, it may be divided into two parts and hinged to one another or it may feature a single sturdy steel structure supported on a roller. When the gate is opened, it can be retracted within the dry dock walls.

  1. Floating Dry Dock

Floating dry docks are U-shaped structures used mainly in salvage, to carry damaged ships that cannot sail further to a coastal dock following an accident. In addition to regular seagoing vessels, many smaller and midsize vessels now dry dock on floating docks. Transporting large vessels is possible by joining various floating docks in the ‘U’ shape.

A floating dry dock will partially submerge as the ship approaches the channel. A floating dock is then deballasted, and the water is drained from its hollow walls and floors, allowing the vessel to rest on the blocks laid out on the dock’s floor.

Floating dry docks are usually constructed using steel framing and ballast tanks along the bottom and sides to control their height. They are used in harbors that are sheltered from the elements and do not have waves or natural tidal activities.

  1. Slipways

A slipway is intended for smaller boats. It consists of an inclined ramp and a moving trolley on which boats can sit. The slipway pulls the boat up onto the land mechanically once the boat is properly aligned with the trolley in the water. Additionally, slipways can be convenient for launching new ships into the water and building new ones. It is common to use paving materials like concrete to construct slipways, while trolleys and tracks are made from metal, wood, or plastic.

Conclusion

A dry sea dock is essential for marine vessels. It is mainly used to expose the underwater parts of the ships or boats for inspection, repair, and maintenance.

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Ellen Hollington

Ellen Hollington is a freelance writer who offers to ghostwrite, copywriting, and blogging services. She works closely with B2C and B2B businesses providing digital marketing content that gains social media attention and increases their search engine visibility.