Indian Navy’s new dry docks: why they are necessary for any naval force

Indian Navy's new dry docks
Indian Navy’s new dry docks


The Indian Navy claims to be in the group of some of the world’s largest navies and operates hundreds of small and large warships and submarines. Endeavor is to maintain the majority of this maritime asset 24/7 on the sea, 7516.6 km is year-round to protect the Indian coastline and various other power launch roles around the world. Technically a warship and a submarine are very complex types of machinery, which require highly talented manpower to operate and maintain the war footing at all times, keeping in mind India’s vast area of ​​interests. The monumental work must also be preserved during the front.

Mumbai Dry Dock:

The dry-dock at Naval Dockyard, Mumbai is the latest asset of the country drowning in the sea as India’s pride. It was almost a decade-long effort to create this unique structure. A large dry-dock was felt by the Indian Navy to include the aircraft carrier INS Vikramaditya, which needed to be kept at sea for maintenance and upkeep. Dry-dock construction was a huge challenge as it is surrounded by the sea on all three sides, with the dock basin jutting 300 meters out to sea. This required cofferdam construction to work on the dry-dock area. It is understood that the dock floor is about one and a half meter thick concrete and a large amount of steel and concrete was used for its construction. It is a modern dry-dock with high automation and can be washed in less than three hours and filled back in just under an hour and a half. Overall, the dry-dock is about 280 meters in length by 45 meters wide and 17 meters deep, which is sufficient to meet the upcoming requirement of dry-docking INS Vikramaditya and indigenously built Vikrant. This dry dock is certainly the pride of the Indian Navy for the time to come.

What are dry-docs?

Drydocking of the ship is a highly planned activity and the process involves moving a vessel into a dry dock basin, closing the Kassen gates and draining the water into the basin using a high power water pump, so that the submerged portions of the hull Can be cleaned, inspected and repaired. This dry-docking process essentially has to be done for every sea voyage to preventive maintenance or any necessary underwater repairs. The steps involved are: –

(a) Entering dry-dock. A dock master prepares the dock floor for each ship by placing special blocks (to sit on the ship) according to the ship’s underwater profile. Nail blocks, as well as bile blocks, are placed on the floor of the dock by the ship’s approved docking plan. All support blocks must conform to the structural members of the ship so that the ship is protected from damage when its weight is supported by the blocks. The blocks are made of specific height so that the sonar dome of the ship has to pass well above the dock floor to avoid damage. With the help of tug boats, the ship is brought to the exact position on the blocks, and the caisson gates are closed. The dry-dock water is drained out slowly, taking care that the ship slowly settles uniformly over the blocks. All alignment checks are performed by the Dock Master’s team so that the ship is vertically balanced before this operation. Living with some water around the ship, the hull cleaning team carried water to clean the sides of the ship for marine development, etc.

(B) Hull inspection and maintenance. Once all of the water is drained out of the dry-dock area, the necessary underwater hull maintenance and repair is carried out, along with routines on underwater equipment such as sonar, sea valves, etc., to balance the ship. Having no machinery is allowed to run onboard. A dry dock is arranged on blocks and special power is provided for the ship because the plow (being the universal ground for the ship) is no longer in conductive seawater! Plow blasting is mainly done to remove rust or defective paint from the side of the ship and remove old paint to expose bare steel. Once blasting is complete, the entire vessel is cleaned and dyed to protect the integrity of the steel and prevent future corrosion. The sea chest for the cooling system in the engine room is a hull for the intake of seawater and is also cleaned with an overhaul of the sea valve. Routines and repairs on the rudder, propeller or shafting are also complete. Finally, the underwater side is painted with anti-fouling paint to prevent marine growth. The ship is usually habitable during the dry-dock period as no air conditioning system is operating, but shore power supplies are provided for progress.

(c) Alignment check. The ship’s radar and weapon alignment were completed during the dry-dock period using various techniques such as star alignment (to remove parallax errors), horizontal alignment check, etc., the ship’s forward and after and horizontality verification checks. is. -Installation. The ship’s heading marker for course measurement w.r.t. True answer alignment is done. Alignment checks for the propeller shaft are also performed during the dry-dock period using laser alignment equipment. Dejasing of the ship is also planned during this period to reduce the ship’s magnetic signature (as protection against activation of magnetic mines). The sacrificial anode, such as the ICCP (Impressed Current Cathodic Protection) system, is replaced during the docking period for the solution corrosion prevention system. There are a plethora of activities performed as SOPs during the dry-dock period.

(d) Dock flooding. After all the maintenance work is completed, the underwater work package, especially the sealed dock using high-pressure pumps, is slowly filled back, and during this activity to ensure a balanced vertical rise on the vessel The movement of personnel is restricted. When the ship is completely away from the block, the kison gates are opened and the ship exits using tug boats.

Maintenance of ships and submarines:

Ships and submarines undergo a highly advanced maintenance scheme that is contemporary and high-tech. The maximum challenge of Float, Move and Fight is no means for a maritime warship that is rigid to men and metal alike, challenging the marine environment. A very stringent maintenance program is followed by these warships and submarines, as a well-defined sequential pattern of boarding ships or short refits (SR) and long refits (LR). These are built primarily around machinery overhauling and repair routines specified by the respective OEMs. They also include SAM, SSM, gas turbines or steam boilers, and such large highly complex systems and the failure of any of these critical systems while ships and submarines are at sea are seen as highly significant organizational defects. According to the Navy SOP, major machinery failures are thoroughly investigated as part of the Technical Board of Inquiry for root cause analysis of any event.

It would be interesting to note here that every machinery that fits on a ship has a maintenance schedule, i.e. from a small motor to the ship’s propeller and large steel hull. The ship’s hull and various accessories such as underwater valves and glands, sonar domes, etc. are important parts of the ship and have a fixed overhauling maintenance schedule as determined by the OEM, and when and underwater failures. Call for repair. The record of all repairs and overhauls is carefully kept as an onrocanque document onboard and regularly kept for inspection by headquarters. Each logbook and equipment repair sheet gives its life story and the onboard manpower is individually tied to these parameters and ensures that peak performance is achieved by all onboard systems. Routine maintenance is carried out for inaccessible equipment and ship hulls which are always submerged in water, especially through dry-dock facilities.

Floating Dry-Docs:

Interestingly, the Indian Navy has a specific type of dry-dock called the Floating Dry-Docks Navy (FDN). These special docks are used for dry-docking of the ship while using the concept of a pontoon at sea. These fans can be transported to locations as required by ships. Whenever a ship has to be dry-docked, FDN valves are opened and the chambers are filled with water, allowing the dry dock to float less in water. The FDN is submerged and it allows the ship to be moved inside. When water is pumped out of the chambers, the dry dock rises and the vessel is pumped out of the water on the mounting deck, allowing it to operate underwater.

Source: Financial Express

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