ORGANIZE AND LEAD THE WAY OF COMPLETE DRY DOCK SHIP’S
TDS company manages multiple facets of the dry docking process including: selecting the correct dry dock to meet a vessels unique requirements, developing a dry docking plan that efficiently meets the vessel’s needs, coordinating with manufacturers or suppliers to procure required parts for the vessel repair, negotiating and coordinating quotes for vessel repair with outside contractors and service providers, coordinating and advising all facets of the repair process, updating the vessel superintendent or head office of progress and procure required repair approvals as necessary, monitoring the repair process to ensure quality and safety measures are met, arranging class surveyors attendance to obtain proper certifications and approvals as required, and providing liability advice in the unlikely event of human errors.
Process: Dry Docking and Launching
A technique used to remove a ship from the water so that the underwater portion may be inspected, repaired, maintained, or altered. Occasionally underwater repairs may be undertaken while a ship is afloat; however, at regular intervals, or as dictated by emergency, it may be necessary to expose all of the underwater portion, regardless of whether the ship is a small harbor tug or a large transoceanic liner.
# To prepare the dry dock, keel blocks are set into position and lines and men to handle the vessel are readied. A qualified dockmaster supervises the operation. Dock-based winches are usually used to position the ship in the dock.
# The most dangerous time in drydocking occurs when support for the ship is changing from water buoyancy to dry dock blocks. If the strength of the blocks is insufficient, they can be crushed, overturning the ship.
# Very large ships (tankers, aircraft carriers) are often constructed in graving docks.
# Ships are often launched as soon as the hull is completed sufficiently to float safely. They are then moved to an outfitting dock for completion.
# Launching from a building berth may be endwise, sidewise, or by in-place flotation.
# Launching from a building dock is performed by flooding the dock to the depth required to float the ship.
# Careful planning and considerable expertise are required to launch a ship by sliding it into the water. Drag chains of predetermined weights are used to control the ship's entry into the water. Tugs are needed to control the ship after entry into the water.
The
four types of dry docks are known as
marine railways, floating dry docks, graving docks, and mechanical lift docks. The size of the ship usually determines which type is used.
The marine railway consists of a cradle of wood or steel with rollers on which the ship may be hauled out of the water along a fixed inclined track leading up the bank of a waterway. The advantages of a marine railway lie in the economy of the original construction and the relative low cost of maintenance. A marine railway is ideal for ships up to 5000 tons.
The floating dry dock may be constructed of wood, steel, or concrete. The dock is submerged, to provide the required depth of water over the keel blocks, by partially filling its tanks with water. The ship to be drydocked is then positioned within, the tanks of the dock are rapidly pumped out by powerful pumps located within the dock walls, and the ship is lifted out of the water.
The graving dock consists of an excavation in the ground with a thick concrete base supported, if necessary, by piling and surrounded on three sides by earth held back by timbers, stone, cement, or steel supports, or a combination of these materials. The entrance, or seaward end of the dock, is usually closed by a caisson of the pontoon type which, when flooded, is trimmed down into position. The dock is flooded, the caisson is floated, and the ship enters the dry dock and is positioned over the keel blocks. The caisson is then replaced and submerged, the dock is pumped out, and the ship settles on the keel blocks. This process is reversed when the ship is ready to leave the dock.
The mechanical lift dock is somewhat similar in action to the floating dry dock. The vessel, after taking up on the keel and bilge blocks in the dock, is bodily lifted clear of the water. The mechanical platform dock has much more flexibility than other types and has increased greatly in size and use.
