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How to utilise maximum hold space in ships loading ? What is broken stowage?

Cargo ships guideline

The shipowner is generally responsible for the stowage of cargo onboard the vessel. In the handling of stowage and carriage of cargo, the following general principles will apply: When loading a general cargo at a variety of ports for a variety of ports, the problem of where to place the individual cargoes must be solved to secure minimum time in port. The cargo must be stowed in reverse order of the intended discharge to avoid rearrangements of the consignments. At the same time the amount of unused space should be kept as low as possible to obtain the best economical use of the vessel.

It is common to distinguish between horizontal and vertical stowage of general cargo in a ship. With horizontal stowage the cargo is spread over a relatively large area, while in vertical loading the consignments are stacked on top of each other so that space can be better utilised.

cargo stowage

Bulk cargoes present little difficulty in stowage, as they can fill up the holds as appropriate. In some cases the cargo needs to be trimmed, i.e. shovelled by hand from high piles in the centre of the hold to the perimeter so that the vessel can be filled up and best utilised.

The given stowage factor of a particular cargo will normally take what is called broken stowage into account.

Broken stowage is space lost because of the shape of the cargo and/or particular requirements in regard to stowing it in the cargo holds. For example, there may be limitations on how many units or consignments which may be placed on top of each other. For homogeneous bulk commodities, broken stowage is usually small. For irregular packages, as often found in typical general cargo lot, it may be substantial.

Broken stoage of paper rolls
Broken stoage of paper rolls

The stowage factor of any cargo is the volume which a certain amount in weight of that cargo occupies. It is usually measures in cubic feet per long ton or alternatively in cubic metres per metric ton. If the stowage factor is 20, it indicates a heavy cargo. If it is 100, it indicates that the cargo is light.

The stowage factor is important for the loading of cargo in the various means of transport, as it indicates the amount of the cargo which can go into the holds. Either the volume or the weight will be the limiting factor. The stowage factors of various products are given in published stowage tables.

While stowage of goods is important for the utilisation of space in containers and holds, packaging and stowage must also be carefully considered in relation to marketing and the needs and specifications of the customers as well as in relation to minimising damage.

Broken Stowage

Any break in stowage­or broken stowage­caused by the presence of pillars, stanchions, brackets, web frames, etc., for the filling of which certain packages are not available, or space which is unsuitable to receive a package of cargo, should be packed firmly with suitable dunnage or airbags, in order to prevent movement of cargo in a seaway and to afford a stable and level platform for the next tier.

The loss of valuable cargo space, where the nature of the cargo justifies economy, is best avoided by:
  1. Compactness of stowage.
  2. Selecting packages which, by the nature and value of their contents and their construction, are suitable for filling broken stowage. Reels of barbed wire, bales of binder twine, coils of small wire, for example, are very useful for this purpose.
  3. Always keeping a supply of such packages, or of low freighted goods, ready at hand in the holds, for use when wanted.
  4. Stowing casks and drums upright rather than on their sides.
  5. Nesting and/or stowing pipes "bell and cantline". Blocking in spaces left between large cases with smaller packages. Care should be taken that these packages cannot become crushed.
  6. Special selection of cargo suitable for filling beam spaces, i.e. cargo which is not liable to chafe or damage by sweat, if moist or heated cargo is carried in the same compartment, or refrigerated cargo in the compartment above. It should be borne in mind that 6­8% of the hold capacity in `tween decks may be contained between the deck beams.

Other useful articles :
  1. Assigning loadlines marks

  2. Loadlines are marks punched into and painted on the sides of general cargo ships.The assigning of the vessels loadline and the issue of the Certificate is the responsibility of the Marine Authority of the country. .
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  3. Cargo ships Loaded Condition

  4. closely monitor the ship's condition during cargo operations to ensure that if a significant deviation from the agreed loading/unloading plan is detected all cargo and ballast operations must STOP..
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  5. Packing a container recommended method

  6. Packing a container should always be done on level plane either on the ground,on a railcar, or on a trailer. In the case of a trailer, care should be taken to ensure the trailer cannot tip whilst being packed especially if a forklift truck is being used. If necessary the trailer should be propped. Brakes should be securely applied and wheels choked.
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  7. Packing principles relating to cargo in containers

  8. Where relevant, stowing should be carried out in a sequence which will permit rapid checking and storage operations during and after unloading. Should the consignment include cargo subject to customs pre-entry procedures, customs examination would be made easier and unloading avoided if the cargo were stowed at the end of the container by the door.
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  9. Container Securing guidance

  10. Containers have very little strength in any direction other than vertically through the corner posts thus it is necessary to provide substantial support to the containers when they are on the ship. Stowage of containers is with their longer dimension fore and aft since the ship motion transmitted to cargo is greater in rolling than pitching and it is therefore prudent to limit any possible cargo movement within the container to the shorter transverse dimension.
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  11. Trim and stability booklet for cargo ships

  12. Contain either curves of form or hydrostatic tables and stability and trim characteristics for various conditions of loading .
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  13. Broken stowage? Cargo ships guideline

  14. The access shall be separate from the hatchway opening, and shall be by a stairway if possible. A fixed ladder, or a line of fixed rungs, shall have no point where they fill a reverse slope .
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  15. Ship type, design and facilities for cargo

  16. Cargo gear is designed for speed and flexibility for handling breakbulk, palletized, or container cargo. Various combinations of derricks, winches, and deck cranes are used for the handling of cargo. Cranes are fitted on many vessels to reduce manpower requirements. Some ships have special heavy-lift derricks that may serve one or more holds. Booms are rigged for either yard and stay (burton) or swinging-boom operation.
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  17. Cargo ships structural plans- how to use them

  18. Structural plans, sometimes called scantlings plans, show dimensions of the ships framing and plating. The midships section drawing, generally available for all ships
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