An Insight into the Process of Dry Docking of Ships
Is it time to dry dock the vessel? Everyone in the marine space relates to dry docking of ships as the ship has to undergo this process several times during its lifetime. The method of dry-docking involves many details and procedures. In this blog post by Alphard Maritime, we will share you with the necessary information about dry docking. It is essential and it’s time to tell you what happens with your precious vessel when it parts from you.
What is Dry Docking?
It refers to the process when a ship is taken to the service yard for repair and maintenance overhaul. During dry docking, the whole ship is brought to the dry land so that the submerged portions of the hull can get inspected and cleaned. A dry dock gets used for this purpose, where the construction of vessels also takes place. It is a regulatory and preventive requirement and set industry standards get adhered to during this process.
The primary objective of dry docking is to expose and inspect the parts of the vessel that remain submerged underwater for a long time. These submerged portions need regular inspection as they endure damages due to seawater and as the size of the ship is massive, dry docking is the only efficient way of maintaining a vessel.
The Procedure of Dry Docking
Dry docking a ship requires intensive and meticulous planning. Read on to know about the step by step dry docking procedure.
- Planning during Pre-Docking: Before the ship comes for dry docking, the dock master prepares a docking plan. This plan includes every little detail like the vessel’s hull structure, the echo sounders, and the location of drain plugs. These details are necessary to avoid any damage to the ship during the process of docking.
- Dock Plan Preparation: Dock master and designers use sketches and get detailed calculations about the height, weight, and structure of the ship. All these details get mentioned in the docking plan as this plan explains how to successfully dock and undock the vessel and avoid any risk of ship capsizing.
- Stability Conditions Ascertained: The stability of the ship is vital during docking. For this, it is essential to ascertain the ship’s weight distribution as the keel blocks primarily bear the weight and any error in calculations can lead to a mishap. Before the actual process begins, it is necessary to know about the stability condition.
- The Ship Arrival: When the ship arrives at the dry-docking port, it must adhere to the required stability conditions. The propeller of the vessel needs to get immersed and it should have the least ballast. Post these checks, the cleaners and dock master board the ship.
- The Docking: After meeting the pre-docking requisites, the vessel gets tugged into the dock, moored, and secured. Then, the cleaning procedures start like pumping out dock water, running the ballast pump and removing the drain plugs.
The Scope of Dry Docking
After the vessel gets dry docked, the essential parts and components get examined for any visible damages. Such an intensive repair and maintenance exercise goes a long way in increasing the productivity of the ship. Some of the maintenance activities carried out during dry docking of the vessel include,
- Gauge the Vessel Thickness: The vessel hull constantly gets exposed to seawater and prone to damages. If there are no visible damages on the vessel hull, still it’s thickness should get tested. There is an ultrasonic gauge for this purpose that measures the time interval between two consecutive echo signals that get reflected from the surface of the hull. It gets looked up as an effective and efficient way of testing as the paint on the hull surface does not impact this calculation.
- Test Via Destructive & Non-Destructive Means: The destructive means of testing involves breaking down certain parts of the ship to test the strength. Later, the rebuilding of these parts takes place with more endurance and strength. The non-destructive means involve testing via visual inspection, liquid penetration technique and ultrasonic testing.
- Intensive Hull Washing: There is a lot of biofuel and dirt that gets deposited on the hull body. When it comes to the dry dock, it undergoes high-pressure washing to remove the algae and other biofuels on the surface that increases the corrosion.
- Blasting & Painting: The process of blasting refers to the protective layer that is put on the hull, making it ready for paint application. After this, a coat of paint gets applied that minimises the corrosion on the hull. This is one of the main tasks carried out during dry-docking. It gives the ship smoothness for efficient operations. Some studies indicate that hull painting also helps in saving the fuel consumption cost of the vessel.
- Other Maintenance Tasks: After the painting process, there is the opening of the sea chests and overhaul of the sea valves. Then, the maintenance work gets carried out on pumps, tanks, and engines.
Drydocking is an intensive process involving much planning and many procedures. There are companies like Altair into dry-docking and ship repairs. Altair Marine Services is a sister concern of the Alphard Maritime group and has its workshop in Dubai Maritime City. Strategically located between Port Rashid and Dubai’s Dry-rocks world, the Maritime City spreads over 249 hectares. The team specialises in dry-docking and afloat service, repair of equipment, components, and fabrication across the Middle East. There are professionals with over years of experience in repairing various types of vessels.
Altair is recognised and accredited with ISO 9001:2015, ISO 14001:2015, OHSAS 18001:2007. For dry-docking, repair, and maintenance of your vessels, connect with the Altair team and benefit from quality service.