Dry Dock Survey for Seagoing Vessels

Dry Dock Survey Requirements

• Ships require a complete survey of the hull in a dry dock twice within a 5-year period and an intermediate survey within 36 months as per SOLAS requirements.

Types of Dry Docks

• There are five main types of dry docks: Graving dock, Floating dock, Marine Rail Dock, Ship lifts, and Marine mobile lifts.

Graving Dry Dock

• A Graving dock is a rectangular solid concrete construction with blocks, walls, and gates near coastal waters.
• The vessel is shifted inside the dry dock and rested on the blocks.
• After the ship is in the required position, the gate is closed and water is removed.

Floating Dry Dock

• A floating dock is a "U" structure used for salvage and repair of damaged ships that cannot sail to a coastal dock.
• It is also used for regular sea-going, small and mid-size vessels.
• Multiple "U" type floating docks can be joined to carry a large vessel.
• The ship is brought near the channel where the floating dry dock will partly submerge itself and the ship slides inside the dock.
• Once the ship is in position, the floating dock is de-ballasted to drain water from its hollow floors and walls to support the vessel on the blocks.