The authors and editors have made every effort to ensure the accuracy of the information contained in the book. History of Container Ships The history of containerization dates back to the mid-20th century. By eliminating unwanted processes, the transit costs of the cargo to be shipped were drastically reduced.
Such containers were soon referred to as FEUs (Forty-foot Equivalent Units) or more commonly, as Two-TEUs. Container units form the most integral part of the entire shipping industry, trade and transport. Some of the most common types of shipping containers in use today are mentioned below:.
Dry storage container
ISO containers are produced in several standard configurations, including dry (or . cube), insulated, flat rack (or platform), open top, refrigerated, and tank. Dry ISO containers are general purpose, fully enclosed, box-type containers used for general transportation and manufactured in standard sizes. The standard width of ISO containers is 8 feet, the standard heights are 8 feet 6 inches and 9 feet 6 inches, and the most common lengths are 20 feet and 40.
Flat rack container
Open top container
Tunnel container
Open side storage container
Double doors container
Refrigerated ISO containers
Tanks
Insulated or thermal containers
Cargo storage roll container
Half-height containers
Car carriers
Intermediate bulk shift containers
Drums
Special purpose containers
Swap bodies
Specific container dimensions and capacity of ISO containers may vary depending on the manufacturer, the age of the container and the owner of the container. The last two alphanumeric characters indicate the type and subtype of the ISO container. Shipping Container Weight: The true weight of an empty container delivered by the manufacturer after the manufacturing process.
The class label is also given on the end door of the container. The cubic capacity or volume of the container is marked on the end door. The evaporator fan circulates air throughout the container by drawing air into the top of the cooling unit and directing the air through the evaporator coil.
Container Ships and Their Design
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Due to the relevance and the ever-increasing demand for better maritime freight transport channels, great progress has been made in container ships. Most of the modern container ships do not have cranes, but some have cargo cranes installed on them, especially in smaller sized ships. Within a container ship, there are also well-defined cargo spaces that separate each container from others, which simplifies the entire filing of the containers.
Container ships represent a majority in terms of the packaged cargo transported around the world. A visual comparison of the hull of a container ship with that of a bulk carrier or an oil tanker will imply that a container ship's hull has a finer shape than the other two. To answer this, we will first need to understand another aspect of the container industry.
To achieve high speed, hull drag must be minimized, which is achieved by a finely shaped hull. That is, the hull section for most of the ship's length is almost rectangular. One of the most critical structural drawings prepared when designing a container ship is that of the midship section.
The midship section of a ship is prepared with many design and functional considerations in mind, including the type of cargo, the stowage methods to be used by the ship, the capacity of the ship, etc. All container ships have a double bottom, so that the double bottom spaces can be used as tanks. The most important structural feature of a container ship is the torsion box, which we will discuss in detail in one of the following sections.
The only decks are within the double hull, which are more like full-length stringers, providing passage along the entire length of the ship.
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However, these are not part of the primary structure; that is, they do not absorb the trunk stresses. Containers loaded above the deck and in front of the navigation bridge must be loaded in such a way that the line of sight from the bridge is not affected. That's why, when you see a loaded container ship, the stack of containers in front of the bridge decreases in height as you move toward the forward-most stack.
Therefore, many ultra-large container ships (eg the Maersk Triple E Class) have their superstructures moved amidships in order to be able to accommodate . full height containers behind the superstructure. Other forms of torque arise from propeller shaft vibration, vibrations due to twin propellers, etc. As the name suggests, wave-induced roll is caused due to the asymmetric hydrodynamic wave loading on the port and starboard sides of the ship. .
If you remove the curler from the rim of the bucket, you will notice this. This leads to even greater bending stresses at the corners of the openings due to the lack of torsional stiffness. The upper part of the double hull of such ships is equipped with a torsion box, as already mentioned.
It is often observed that the main deck is subjected to high torsional moments and tensioning effects, and the deck clearance in the path of the hatch opening along the transverse side is very less. As a result, stress concentration can cause cracks at the corners of the flaps or cracks in the deck itself. It helps prevent torsional buckling on ships due to torsional moment on the vessel deck caused by dynamic wave motion.
Extreme loads on the container and their securing system, resulting in failure of the same and even loss of containers.
Cargo Operation
The Verified Gross Mass or VGM is the combined weight of the tare weight of the container and weight of all cargo, including all packaging and bracing. Any query regarding the weight of the container can be found from the container markings, which include the tare weight and MGW. The shipper, whose name is mentioned in the bill of lading, is responsible for providing the VGM of the packed container in good time to the ship's personnel and the port terminals.
These margins of error are small and will not compromise the safety of the ship. The master of the ship is responsible for ensuring that only packaged cargo with VGM documentation is on board. The captain and manager of the shipping company must ensure that the VGM of the package shipment is reported in the cargo documents.
Master must ensure that the loading plan software on board the ship takes into account the VGM of the cargo. Availability of the verified gross mass of a packed container to the Master of the ship on which it is to be loaded is therefore a prerequisite. We must take all possible steps positively regarding the safety of the vessel and the environment.
An efficient ballast plan should be prepared according to the condition of the ship before arrival. Container ships play a crucial role in the economy and are therefore an essential part of the shipping industry. The time of start of the loading and unloading activities is recorded in the freight registration book together with the track number.
THE BEAM is the position where the container is placed across the width of the ship. If the container is placed on the centerline of the vessel, it will receive a row of 00. Maximum Gross Operating Weight: This is the maximum allowable total weight of the container and its cargo.
Securing Containers
As a deck officer on a ship, your main responsibilities are to navigate the ship safely and handle and stow cargo safely. As the rank or responsibility of the deck officer increases, knowledge of cargo handling and storage is indispensable to a competent deck officer for the safety of the ship's property and personnel. If possible, stowing OOG on the deck of the second forwardmost compartment should also be avoided;
Before arriving at the port, ship's crew usually release the container so that time can be saved in the port and the containers can be unloaded. All lashing straps and other materials must be removed and secured from the top of the hatch cover prior to its removal. Before the cargo operation begins, the chief officer must inspect work areas and cargo handling equipment to ensure the safety of the ship's . staff and stevedores.
He/she must also check that the tightening is done correctly to ensure the safety of the cargo containers when the ship is at sea. If the current draft deviates too much .. from the planned launch draft, it should be brought to the attention of the chief mate. Any loading or unloading of containers that does not conform to the storage plan must be noted and brought to the attention of the supervisor and planner.
The set points of coolers, electrical connections, terminals, water hose connections should be checked carefully. The intensity of the search will depend on the security level of the vessel and the port. The position of the gearboxes to be loaded should be informed to the loader well inside.
Once loaded, the duty officer must visually inspect and confirm the position of the gearboxes and record it. Regular rounds of the cargo deck area should be made to check the condition of the moorings and cargo containers. In such cases, the master of the vessel must take the necessary precautions to reduce.
