Wednesday, September 23, 2009

Aspects of Cargo Work Routine

Accepting Cargo: Loads for shipment should be properly packed, i.e. securely and safety, and adequately marked in order to indicate weight, poll marks, slinging points and, where necessary, any special precautions. Deficiencies in those directions should he questioned.Where cargo is pre-slung attention must he given to the system of support which holds the load together as one unit, in stowage, pre-slung loads must he effectively blocked off so as to avoid inter-cargo damage from contact movement or displacement while crushing damage must be avoided by a sufficiency of dunnage/plyboard or synthetic packing between the layers or tiers of the pre-slung units.Pre-slinging is becoming increasingly adaptable to many types (if loads by reason, among other tilings, of its time, and labour saving advantages.Bulky Lifts. The position of the centre of gravity of a load should, preferably, be indicated on the outside of (he packaging. This allows of collect balancing in slinging, avoids any danger of accident while the load is in suspension while, with fork lift truck movement, permits of equal weight distribution over the machine. Attention in these respects is important and should have regard lo the known gross weight of the load being handled ami the type of its contents.Insufficient attention to this procedure can raise difficulties both in lifting and in stowing since it does not follow that the centre of gravity of the 'content', i.e. for example, a machinery unit, coincides willi the geometrical centre of the overall package.Pallets. Where cargo is loaded to be slowed on pallets, these should be in good order and condition and devoid of signs of collapsing under weight stress. Cargo on pallets should be loaded in such a way as to be evenly distributed, not irregular nor overhanging at the sides. The interlocking of the goods on the pallet, known as bonding, is much the preferable method.Unitization involves a high measure of palletized cargo.Unit Stowage. All forms of unit stowage require even distribution, to which end 'dunnage' of appropriate form should be sensibly used. Plywood sheets, placed between each layer ol a unit slow, is a heller system in achieving a level surface and so preventing an otherwise intrusion of damaging causes from oilier cargo 'pieces'. Indeed, such arrangements are encouraged when loading containers on to the hatchways of tween decks as pan of a multi-stow.Containers . . . ex quay. The cargo officer's involvement with cargo slowed in containers is where 'stuffing' is the practice. Stuffing is loading the container, ex quay, prior to shipment, from a variety of relatively small sized consignments.Stuffing should follow the normally accepted principles of good slowage but, in particular, the following precautions are necessary.The total load weight should be evenly distributed over the floor of the container such that the centre of gravity is low, and as near lo the centre ol gravity of the container as is possible.Lighter cargo should be slowed on lop of heaviei ; precautions against contamination taken and choking off, in order to obtain a tight and solid load is essential.Particular care should be exercised with goods of a damp or oily texture. This could inhibit a fire risk from spontaneous combustion. Where doubt arises, such goods should be rejected.Stuffing calls for careful supervision . . . careful in the sense that labour employed may not always be of the usual high standards of normal stevedores nor is the environment of a single box as conducive to 'job satisfaction' as the normal hold/space cargo working operations. Lack of appropriate attention to the loading of the box could well lead lo difficulties later, when the vessel would be at sea.

Ship Handling Effects Of Banks, Channels, and Shallow Water

A ship moving through shallow water experiences pronounced effects from the proximity of the nearby bottom. Similarly, a ship in a channel will be affected by the proximity of the sides of the channel. These effects can easily cause errors in piloting which lead to grounding. The effects are known as squat, bank cushion, and bank suction. They are more fully explained in texts on ship handling, but certain navigational aspects are discussed below.

Squat is caused by the interaction of the hull of the ship, the bottom, and the water between. As a ship moves through shallow water, some of the water it displaces rushes under the vessel to rise again at the stern. This causes a venturi effect, decreasing upward pressure on the hull. Squat makes the ship sink deeper in the water than normal and slows the vessel. The faster the ship moves through shallow water, the greater is this effect; groundings on both charted and uncharted shoals and rocks have occurred because of this phenomenon, when at reduced speed the ship could have safely cleared the dangers. When navigating in shallow water, the navigator must reduce speed to avoid squat. If bow and stern waves nearly perpendicular the direction of travel are noticed, and the vessel slows with no change in shaft speed, squat is occurring. Immediately slow the ship to counter it. Squatting occurs in deep water also, but is more pronounced and dangerous in shoal water. The large waves generated by a squatting ship also endanger shore facilities and other craft.

Bank cushion is the effect on a ship approaching a steep underwater bank at an oblique angle. As water is forced into the narrowing gap between the ship's bow and the shore, it tends to rise or pile up on the landward side, causing the ship to sheer away from the bank.

Bank suction occurs at the stern of a ship in a narrow channel. Water rushing past the ship on the landward side exerts less force than water on the opposite or open water side. This effect can actually be seen as a difference in draft readings from one side of the vessel to the other, and is similar to the venturi effect seen in squat. The stern of the ship is forced toward the bank. If the ship gets too close to the bank, it can be forced sideways into it. The same effect occurs between two vessels passing close to each other.

These effects increase as speed increases. Therefore, in shallow water and narrow channels, navigators should decrease speed tominimize these effects. Skilled pilots may use these effects to advantage in particular situations, but the average mariner's best choice is slow speed and careful attention to piloting.

Preparation of Dry Docking

Dry Dock Periods

A docking survey should be carried out twice within a 5 year period. The intermediate survey must be completed within 3 years. One of the two docking surveys within the 5 year period should coincide with a special survey. A Docking Survey is considered to coincide with the Special Survey when held within the 15 months prior to the due date of the Special Survey. An in water survey may be accepted in lieu of the intermediate survey For vessels operating in fresh water special consideration may be given.

In-water Surveys
An In-water Survey may be accepted in lieu of the intermediate docking between Special Surveys, an *IWS notation is assigned. This requires suitable underwater protection for the hull in part taking the form of high resistance paint. This survey is to provide information normally obtained from a docking survey.
The In-water Survey is to be carried out at agreed geographical locations under the surveillance of a Surveyor to LR, with the ship at a suitable draught in sheltered waters; the in-water visibility is to be good and the hull below the waterline is to be clean. The Surveyor is to be satisfied that the method of pictorial presentation is satisfactory. There is to be good two-way communication between the Surveyor and the appropriately qualified diver.

Should damage be found a dry dock may be required for better inspection

Dry Dock file
Preparation for dry dock begins after the ship sails from its previous one. A dry-dock list of new items is created with specification sheets describing individual jobs. These sheets are compiled into a dry dock file which some time before the due date of the docking is submitted to several dry docks for pricing.

The jobs are priced individually and as a whole. This allows the ship managers to streamline the jobs to provide maximum value for money.

The vessel must be prepared before entering the dry dock. Structural loading must be taken into account as the vessel is to be point supported on blocks. A docking plan of the ships which shows such things as drain plugs, sea boxes, underwater attachments etc is sent to the dry dock. Added to this are indications where hull repairs are required. This allows the drydock ship managers to place the blocks on which the vessel will sit.
The vessel must be trimmed so as to be equal draught with zero list. Special attention should be made when planning this for any tanks whose contents may be varied due to repair or housekeeping requirements.

In dock
The safety and fire fighting responsibilities of the vessel are handed over to the dry dock safety department for the duration of the dry and wet dock period. All hot work, tank entry or jobs requiring special safety measures carried out by ships crew must be first agreed with the dry dock safety department. A daily meeting is held to discuss forth coming jobs and any special requirements. This also allows the vessels staff and company representatives to monitor the progress of the dock.

Inspections & Measurements
Where a ship is in dry-dock or on a slipway it is to be placed on blocks of sufficient height, and proper staging is to be erected as may be necessary, for the examination of the shell including bottom and bow plating, keel, stern, sternframe and rudder. The rudder is to be lifted for examination of the pintles if considered necessary by the Surveyor.

Attention is to be given to parts of the structure particularly liable to excessive corrosion or to deterioration from causes, such as chafing and lying on the ground, and to any undue unfairness of the plating of the bottom.
The clearances in the rudder bearings are to be measured.
The sea connections and overboard discharge valves and their attachments to the hull are to be examined.
The propeller, sternbush and sea connection fastenings and the gratings at the sea inlets are to be examined.
The clearance in the sternbush or the efficiency of the oil glands is to be ascertained.
When chain cables are ranged, the anchors and cables are to be examined by the Surveyor.

Cargo Broken Stowage

To clearly understand about the Cargo broken stowage. will explain you little bit more, that artikel to bring it you sample as follows:
Example 50 tons of general cargo. Stowage factor 40 cubic feet per ton. Broken stowage 5 percent. Loaded into a space containing 6000 cubic feet. What is the space remaining?

Broken stowage explains space 'lost' in a compartment. This loss of space is due mainly to the variable sizes of packages loaded into a compartment, thus preventing a compact and uniform stow. It is most unlikely that a general cargo will provide many cases or packages of uniform size and, though all due care may be taken in stowing them, it is almost impossible to prevent loss of space between some packages, having regard to the questions of preventing crushing and shitting. This loss of space is increased in those parts of the vessel which are not conducive to compactness of stow and here broken stowage will reach a high ratio. With general cargo stowed in end holds, the triangular shape of these holds will not permit a solid or uniform slow.

Obstructions in holds, such as pillars, ladders, stanchions, large angle brackets and beams, will promote broken stowage though modern construction has minimized this.
Broken stowage can be of considerable magnitude with a general cargo, whilst with most bulk cargoes it may be very small.
Most cargoes require wooden dunnage for their successful carriage, but the inconsiderate use of this dunnage can constitute an element of broken stowage, for unnecessary amounts would involve the use of space, the aggregate of which would represent quite a considerable volume.
Discretion in the utilization of cargo space is important for it must be fully realized that the amount of cargo loaded into a vessel directly affects her freight earning capability.
On most established trades cargo is booked for the vessel before her arrival and unless due attention is given to the stowage factor of cargo and care taken to adhere to that figure as nearly as possible, the vessel may arrive at subsequent ports, unable to take the booked quota owing to lack of space.
On some trades, small cargo of particular type is shipped and carried at a low rate of freight, for the express purpose of filling in the open spaces between the packages and at the ends and sides of the main stow, thus reducing broken stowage.
The term 'Broken Stowage Cargo' covers these commodities, though the term 'Broken Stowage' is more correctly associated with the 'loss of space'.
Attention is drawn to the fact that the amount of broken stow¬age is related to the cargo and not to the space in which it 's stowed.