Containers

This module allows you to define the location and number of containers in each container bay, and also various container loading configurations for use in Loading Conditions.

Calc splits containerisation into two distinct areas. The first area is the definition of notional container slots or positions that the design of the vessel provides for, including consideration of containers that are mounted on hatch covers and also for hatch-coverless designs. These slots or positions are thus all the possible locations within the vessel that may be used for the conveyance of containers. The second area is the definition of a complete vessel voyage condition container layout, representing the subset, and the loading of cargo weights into each container within the defined layout, thus allowing for both full and empty individual containers. Thus, a logical sequence of steps needs to be followed in order to define a full voyage condition container load subset.

Calc uses the normal convention of bays for locating container loading positions within a hold, vertically extended to include the zone above hatch covers, if and where relevant. The locations of bays would themselves be established by the arrangements of container guides, thus forming the physical slots for specific types of containers.

1. Container Types.

   Before any container slots can be defined, you need to define the container type that each bay/slot is designed to accommodate. Each container type is modelled as a rectangular box, described by its length, width and height. Other parameters, such as the standard separation spacing allowances from adjacent containers, weight empty and weight full, , are entered for a container type, with the system providing standard default values. This data is then used by Calc for various validation checks and when generating default data. There are a number of specific container types (namely 9 ISO and 6 Special types) which are supplied as defaults. These can be edited and further types entered.

   you should appreciate that the container facilities could also be used for any unitised break-bulk cargo component that can reasonably be represented by a general rectangular box, for example, pallets and vehicles with appropriate allowances being made for separation spacings,

2. Container Loading Positions.

   The next task is to define the various bays within the vessel. A bay is to provide for a set of containers (of one single particular type) bounded by two transverse planes through the ship, and made up of tiers (like waterlines) and rows (like buttocks).

   A bay's centreline reference location is defined by the longitudinal (X) and vertical (Z) position of the aft corner of the bottom container tier in the bay. You start by specifying the maximum number of tiers and rows within the bay, creating a maximum locating grid size. This maximum size will be a function of the vessel's size (breadth and depth, and with allowances for internal structure, for example, the hold side and inner bottom surfaces) at this specific location. From the information defined for the container type, Calc is able to automatically create the vertical height of the container bases (measured from the defined Z) and the TCGs, of each container in the bay. This information is presented and developed in the form of two identical spreadsheets (one for the vertical and one for the transverse locations) where each cell represents a container slot in that bay. you may edit any of these values if necessary.

   As a result of the vessel's shape, some container slots defined above may not be physically possible, that means, they lie entirely or partially outside the limit of the hold structural surfaces bounding the particular bay. Thus, these cells need to be deactivated. This is achieved by you re-selecting the number of rows in lower tiers, creating symmetric tapering. The possibility of an unsymmetric distribution of container slots in a row can arise as a result of other design constraints, for example, a stern ramp which prevents the placement of containers on one side. (This could also occur if this containerisation facility was being used to model the equivalent of units of break-bulk cargo, as noted earlier.) Thus a user can also deactivate cells representing particular container slots.

   In some designs the presence of structural members at the strength deck level, for example, torsion boxes on the centreline, will also impose on the space that is otherwise available for containers and you will need to make allowance for such, possibly through controlling the transverse distances.

   In order to aid you in defining the container arrangement within a bay, it is possible to graphically view a particular bay, once generated. The view displays the two hull transverse sections, from the original hull input geometry, located at the forward and aft extents of the defined bay, together with each container slot (in the colour defined for the relevant container type). With this window in the background and the Bay Definition dialog open, the bay definition (corresponding to the bay in the view) may be edited, if required.

   you can also use this process in order to place tiers and rows of containers on top of the local hatch cover. you can introduce a local bay title in order to represent such an arrangement and where the container type may differ from the one in the bay/hold space immediately below the hatch cover. The ship hull geometry that is input into Calc is unlikely to contain hatch cover and coaming dimensions, and hence you must allow for such in his input data for the bay’s location.

   you continues this process and defines all the bays necessary, which will include all the possible locations to be considered and all the different combinations of container types to be considered for different overall layout combinations. The next step is to define a particular voyage configuration layout combination and to load the corresponding containers.

   It is to be noted that the container types and layout definition data could be copied to another parallel branch in the Application Tree in order to be used as the basis to create another container voyage subset.

3. Loading Containers into Vessel.

   Once all of the bay definitions have been created it is then possible to create the container voyage load subset, that is identifying which of the available slots are actually filled with a container. There are two steps; firstly the selection of a combination of bays creating a bay set, (thus containing the full complement of containers required for a sailing condition) and secondly specifying the actual weight to be held by each container.

   The first task is for you to select the bays to be included and that are to be loaded with containers in the subset. It is to be noted that a bay set cannot include bays that geometrically overlap within their vertical extent, as containers cannot occupy the same physical space. Clearly you need to allow for containers of different lengths, Calc prevents this possibility by indicating unselectable bays as red. The bay clash check works in both the longitudinal and vertical extents and includes the minimum separations specified for the relevant container types.

   It is then necessary to define the weight of each individual container within the generated set. Note that by default, the weight of each container is the empty weight specified for the relevant container type, unless you specify otherwise. Through the spreadsheets that represent each bay definition, you are able to enter specific weight values (the combined weight of the container and internal contents item), making use of copy and paste functions to speed up the process. Also provided are Full and Empty buttons which can be used to enter the values defined for the container type, in the highlighted cells.