Safe Stowage Onboard Vessels PDF

Safe Stowage onboard Vessels Presented by: Suzette Balkaran The proper stowage and securing of cargoes is of the utmost importance for the safety of life at sea. Improper stowage and securing of cargoes has resulted in numerous serious ship casualties and caused injury and loss of life, not only at...

Safe Stowage onboard Vessels Presented by: Suzette Balkaran The proper stowage and securing of cargoes is of the utmost importance for the safety of life at sea. Improper stowage and securing of cargoes has resulted in numerous serious ship casualties and caused injury and loss of life, not only at sea but also during loading and discharge (IMO 2020). Forces exerted on ships and cargoes Cargo Transport A ship can carry different types of cargo which includes oil cargo, chemical cargo, and cargo in gaseous form. These types of goods can be hazardous for marine environment as well as for the health of seafarer. Other than carrying cargo, the ship carries different types of chemicals and solutions which are used for several marine operations. A Material Safety Data Sheet is provided for such cargo and also for chemicals carried onboard which are used for maintenance purpose. MSDS Hazard Icons Purpose of the MSDS Ensures the safety of marine environment and seafarers Provides useful and accessible information on the product carried on board, either as a cargo or for operational purposes Promotes proper personal protective equipment (PPE) to be kept on board, for cases of emergency, to ensure appropriate procedures and swift responses Legislative Requirements As per SOLAS regulation 5-1 complying with ISM code, Merchant ships are mandated to carry MSDS onboard, if ships are carrying cargo or bunker falling under MARPOL Annex I Content of MSDS Hazard Identification along with identification of the mixture or content Composition or information of the ingredients Fire fighting measures First aid measures Accidental release measure Handling and storage criteria Personal protection and exposal control methods Chemical and physical properties of the mixture Information about the toxicity of the material Ecological and Disposal information Transport and regulatory information Additional information on the preparation and revision of MSDS Hazardous materials on board Goods present on board ships that can be hazardous to the ship and its crew are: Different hazardous goods like fuel oil, lube oil, chemicals, LNG, LPG etc Cargo carried in containers under IMDG code Fuel oil and lube oil carried as a bunker are also hazardous in nature and can harm humans and environment For maintenance and operational purpose, different kinds of chemicals are used onboard which can be hazardous. They are mostly used as cleaning agents, for water treatments, for dosing in fuels and as an additive in sanitation systems. IMDG CODE Transport of dangerous goods by sea is regulated by International Maritime Dangerous Goods Code (IMDG Code) in order to prevent injury to persons or damage to ships and their cargoes. Transport of marine pollutants is primarily regulated to prevent harm to the marine environment. The objective of the IMDG Code is to enhance the safe transport of dangerous goods while facilitating the free unrestricted movement of such goods. The IMDG is the collection of rules and regulations that dictates safe practices for the maritime transport of various hazardous materials. It divides dangerous goods into nine categories and establishes policies and procedures for handling each one.  Categories of Dangerous Goods The nine hazardous class categories as listed in the IMDG Code are: Class 1: Explosives Examples: fireworks, ammunition, rockets, explosive charges, airbag inflators. Class 2: Gases Examples: aerosols, refrigerant gases such as Freon, propane, natural gas. Class 3: Flammable Liquids Examples: alcohols, lacquers and varnishes, gasoline, diesel fuel. Class 4: Flammable Solids Examples: metal powders, phosphorous, matches, celluloid. Class 5: Oxidizing Substances and Organic Peroxides Examples: ammonium nitrate fertilizers, chemical oxygen generators, hydrogen peroxide. Class 6: Toxic and Infectious Substances Examples: medical waste, biological specimens, mercury compounds. Class 7: Radioactive Substances Examples: uranium compounds, radioactive ores, medical isotopes. Class 8: Corrosives Examples: batteries, acids, formaldehyde, fire extinguisher charges. Class 9: Miscellaneous Hazardous Goods Examples: dry ice, internal combustion engines, magnetized materials, life saving devices. Stowage Categories Positioning of dangerous goods containers on board vessels are categorised by ‘stowage categories’ to ensure safety. Many points are considered by IMDG Code for safe carriage of dangerous goods by sea-going vessels. On ships there are two different types of stowage (1) On deck and (2) Under Deck. For every dangerous goods listed in IMDG Code Dangerous Goods List column 16 specifies stowage requirement. This is indicated by Category A, B , C, D or E. On Deck only stowage is always prescribed for cases where: constant supervision is required; or accessibility is particularly required; or there is a substantial risk of formation of explosive gas mixtures, development of highly toxic vapours, or unobserved corrosion of the ship STOWAGE ARRANGEMENTS No matter the cargo type, all items must be stowed in a manner that is appropriate and that allows the items to be secured, and such that they will not move significantly or suffer damage. There are three main stowage arrangements Cross stowage Side stowage Single stowage Cross stowage arrangements Cross stowage is where cargo items are stowed in an athwartships block extending continuously from ship’s side to ship’s side or to a fixed structure such as a longitudinal bulkhead. Types of cargoes suitable for cross- stowage arrangements include cases of machinery, pallets, coils of steel sheet and bales. Side Stowage Arrangements Side stowage is where cargo items are stowed against the ship’s side or a longitudinal bulkhead so that the ship’s structure provides support against transverse forces on one side only.. Break-bulk items such as drums, pallets or cases of machinery might be given side stowage in one side of a ’tween deck while the square is occupied by containers or units in single stowage. Single Stowage Arrangements Single stowage is for units of cargo that must be secured individually and must, therefore, be stowed alone, and with space all around on the tank top, ’tween deck or on deck. Examples include heavy- lift items, containers on non- container ships and ro-ro items.  CARGO SECURING METHODS Goods should be prevented from sliding and tipping in forward, backward and sideways directions by locking, blocking, lashing or a combination of these methods. Items of cargo will either slide or tip over depending upon their shape and size, the position of the centre of gravity and the coefficient of friction between the cargo and the deck. Blocking and Bracing Blocking means that the cargo is stowed against fixed Cargo transport unit CTU blocking structures and fixtures on the CTU. Clumps, means a transport vehicle, a wedges, dunnage, stanchions, inflatable dunnage bags freight container, a portable and other devices which are supported directly or indirectly by fixed blocking structures are also tank or a multiple element considered as blocking. gas container. A closed cargo transport Blocking is primarily a method to prevent the cargo from sliding, but if the blocking reaches high enough, it also unit means a cargo transport prevents tipping. Blocking is the primary method for unit in which the contents are cargo securing and should be used as far as possible. totally enclosed by The sum of void spaces in any horizontal direction permanent structures. should not exceed 15 cm. However, between dense rigid An open cargo transport cargo items, such as steel, concrete or stone, the void unit means a cargo transport spaces should be further minimized, as far as possible. unit that is not a closed cargo transport unit. Top–over lashing Top–over lashings preventing tipping forward and backward should be placed symmetrically on the cargo. Half-loop lashing A pair of half-loop lashings prevents cargo from sliding and tipping sideways. Minimum one pair of half-loop lashings per section should be used. LASHINGS, DUNNAGE, FRICTION AND SLIDE OR TIP OVER When the appropriate stowage location for a particular item of cargo has been decided upon, thought must then be given to dunnaging and securing the item so that it will not move. There are many types of lashing equipment and many different types of dunnaging material, and only those that are appropriate for the particular cargo should be used, and used correctly, to increase friction, to support the piece of cargo and to prevent it from moving. Lashing materials Wire does stretch when in use; new wire will initially permanently stretch while it is settling and compacting, and will display an elastic stretch while in use, as load increases. The cargo itself might move a little and settle, lashings must be checked and re- tightened as necessary at intervals throughout the voyage. When wire is used to make lashings the wire must be formed into eyes or into loops by the use of wire rope grips. A rope grip comprises a U-bolt, two nuts and a cast steel saddle. Rules for making a wire rope eye with grips The grips must be the correct size for the diameter of the wire in use. The correct number of grips must be used. All grips must be the same way round, with the saddle on the weight bearing part of the wire. The first grip must be close to the thimble if one is used. The other grips must be spaced six rope diameters apart. The cut end must be whipped or secured in some way and there must be no unlaying of the dead end of the wire and the dead end must be of length about six rope diameters. The nuts should be tightened until the U-bolt bites into the wire. When an eye is made up correctly the wire will not slip through the grips until the load on the wire is about 70% of its nominal breaking strength. Shackles and turnbuckles Shackles and turnbuckles are are used in conjunction with wire rope and chain lashings. A size appropriate to the size of the wire or chain, and appropriate to the lashing points on the piece of cargo and on deck, should be chosen. All threads should be well greased and free. The items should be in good condition, without defect or deformity. Chains Chains are mainly used for the securing of containers, items of ro-ro cargo, heavy-lift items and timber deck cargoes. The main advantage of chain is that it does not stretch appreciably under normal loadings and can therefore be set tight when being fitted. Chains, like other lashings, must be checked and re-tightened as necessary at intervals throughout the voyage. Fibre rope Fibre rope can be used as frapping to tighten a wire rope, but a rigging screw should not be used to tension a fibre rope. Frapping is the use of a number of turns of fibre rope between the eye in a wire rope and a D-ring to gain mechanical advantage to tighten the wire and to achieve strength in the number of turns. Webbing Webbing lashings may also be used for the securing of a wide range of cargo items on board, many of which cannot be secured by other means. These include contact-sensitive pipes and cylinders, yachts and other small craft, and cases or other items that are not provided with lashing points. Webbing has stretch characteristics similar to those of wire rope. Steel bands Steel bands or straps are widely used for the securing of steel products in open stowage in the holds of ships, and for the securing of many types of cargo items in closed containers or on flat-rack containers, and on road trailers. Steel bands are lighter and easier to use than wire of the same strength and banding is much cheaper than is wire. Sea fastenings The term sea fastenings is given to securing arrangements that comprise large-section timber and/or steel girders that are variously bolted or welded together and to the ship’s structure to form chocks either against, under, over or around a piece of cargo to support that piece of cargo and to prevent it from moving. Sea fastenings are used for the securing of heavy items, those without sufficient lashing points and those which cannot be secured by any other method. Sea fastenings may be used in conjunction with conventional lashings of wires, chains or webbing straps. Container lashing equipment Container ships are provided with specialised container lashing equipment. That equipment may comprise lashing rods or chains, turnbuckles, twistlocks, single and double cones, bridge-fittings, deck studs and corner locators. Some ships will be fitted with cell guides and others with tension- pressure elements for the securing of under-deck containers. There are also various other fittings, both fixed and portable, which can be supplied. Container lashing equipment is only to be used for the lashing of containers, and containers on container ships must only be secured using the specially designed equipment as specified in the ship’s approved Cargo Securing Manual. Choice of lashing arrangements The lashing arrangements must prevent the cargo from moving as the ship rolls and pitches in the ocean. The arrangements must be efficient, there is no point fitting a lashing that has no effect, and the arrangements must be appropriate to the type of cargo. Lashings can be either: direct lashings loop lashings compacting lashing. Direct lashings When a piece of cargo is provided with lashing points or fittings that can be used to take lashings, direct lashings can be fitted to those points or fittings and then led to the ship’s lashing points or strong fittings. Lashings to prevent transverse or longitudinal sliding should be fitted at a lower angle, whereas lashings to prevent transverse tipping should be fitted at a higher angle. Loop lashings Loops can be fitted to single units that have no lashing points and to blocks of cargo stowed against the ship’s side. These lashings have a positive securing effect in one direction only, and both parts of the lashing can be counted for the balance of forces calculation. However, they must be fitted in pairs, one acting to port and one acting to starboard. Compacting lashings Cargo items stowed in a cross-stowage arrangement and which, by their nature, have no lashing points may be provided with compacting lashings to hold individual items. Care of lashing materials When not in use lashing materials must be kept in a suitable clean, dry storage area away from chemicals or other stores items that might cause them damage. Moving parts of items such as shackles and turnbuckles should be kept lubricated and free. All pieces of lashing equipment should be thoroughly inspected at regular intervals and all damaged, heavily worn or otherwise defective pieces should be discarded or put to one side pending repairs. Whenever items are brought out of storage and into use to secure cargo, an examination should be carried out to confirm that they are still in satisfactory working order. When new pieces are brought on board they should be inspected to confirm that they are the items that were ordered and that they are in good condition. Whenever the ship’s outfit of portable cargo securing devices changes, those changes should be recorded in the appropriate section of the Cargo Securing Manual. An appropriate record should be completed whenever routine visual examinations or periodic detailed examinations and re-testing of the devices are carried out. Dunnage The term dunnage includes the various materials that are used to protect, separate and support items of cargo. Types of dunnage include: Timber in the form of flat boards Various types of paper including reinforced and water-resistant Polythene sheeting and other synthetic or natural fibre material sheeting Air bags in a range of sizes Various types of poles and woven mats Function of Dunnage Role of dunnage in stowage and securing: To protect cargo from contact with the ship’s steelwork To support one shipment of cargo loaded on top of another, in the form of timber, plywood sheets or steel sheets and plates To support cargo against tipping To spread the load of the cargo across the hatch, deck or tank-top To increase the friction between the base of the cargo item and the hatch, deck or tank top upon which it is stowed. Friction Whenever two surfaces are in contact and are either static or sliding over each other, there will be a friction force acting against any force which is causing or is likely to cause movement. That friction force is dependent upon the coefficient of friction (µ) between the two surfaces. For a piece of cargo placed on the deck of a ship the friction force, or rather the force required to overcome that friction force and therefore required to move that piece of cargo across the deck, can be calculated by multiplying the weight of the item (mass × gravitational pull) by the coefficient of friction of the two surfaces. Friction Friction coefficient Thus, the larger the friction coefficient of the contact surfaces, the larger will be the force required to slide the item of cargo across the deck. The magnitude of the coefficient of friction is dependent upon the nature of the two surfaces and whether or not they are lubricated. In the CSS Code the most useful friction coefficients, so far as the securing of cargo are concerned, are given below: Use of lashings The additional external forces will cause a piece of cargo to slide over the deck at an angle less than that which is equivalent to the friction coefficient of the two surfaces. Lashings, when properly fitted and tensioned, will stop the piece of cargo from sliding across the deck. This is done by the components of the lashings acting variously vertically down and horizontally. Vertical components will effectively increase the friction coefficient, which will mean that a larger external force will be necessary before movement takes place. Horizontal components will act in line with the external forces, again meaning that larger external forces will be needed before movement takes place. The components of the lashings will also prevent a piece of cargo from tipping over. Slide or tip Items of cargo that have a low centre of gravity and a large base area are likely to slide before they tip over, whereas items of cargo with a small base area and a high centre of gravity are likely to tip over at a roll angle far less than that required for the piece of cargo to slide. When deciding upon the type of lashings and dunnage to be used in the securing of the piece of cargo, its size, shape and the position of its centre of gravity must be taken into account. To prevent a piece of cargo from sliding, the coefficient of friction between its base and the deck must be increased as much as possible, for example by the fitting of rubber matting below the piece, if appropriate, and by fitting low-level chocking or lashings to act against the forces that will produce the sliding motion. To prevent an item with a high centre of gravity from tipping over, the item must be fitted with lashings, fitted to the upper part of the cargo item. These, of course, being in addition to other chocking or lashing at lower levels that must be fitted to counteract the always-present sliding forces. Sliding and Tipping Break-bulk cargo Break-bulk cargo items include all classes of cargo that do not come under a specific heading, as do heavy-lift items and ro-ro cargo, and therefore do not have specific requirements in terms of stowage and securing. That does not mean, however, that there are no rules to be followed with regard to the safe carriage of such items. The CSS Code includes some guidance on the safe stowage and securing of portable tanks, portable receptacles and unit loads, in annexes 2, 3 and 12 respectively, and that guidance can be applied to the carriage of most break-bulk or general cargo items. These items have two things in common: they have no lashing points, and they either cannot be loaded one atop another or they have a limited over-stow load. Cartons, pallets and drums Small-sized and medium-sized regular items such as cartons, pallets and drums can be block-stowed together against a bulkhead or against the ship’s side, or both, and then secured to that bulkhead and/or ship’s side structure. Reels of cable Reels of cable come in a range of sizes and are dealt with here in isolation because they have special needs. Most are of timber construction although a small proportion of the larger size reels are of steel construction. The reels on which the cable is wound are, usually, for single-trip use and will therefore be discarded when the cable is taken into use. This means that the reels are not heavily constructed and will suffer damage if mishandled. Always remember the cable wound onto the reels will be of high value. HEAVY-LIFT ITEMS AND PROJECT CARGO Heavy-lift items and project cargo are often of high value and great weight. They may have delicate parts that must not be contacted and they may or may not be suitable for carriage on deck, which will undoubtedly mean wetting by rain and sea water. They must be fitted with lifting points and lashing points that are of adequate strength and positioned in appropriate places. The carriage of these items should be planned in great detail from origin to destination. Of particular interest here is the planning of the stowage and securing. Planning Voyage planning: The voyage must be planned to ensure that the piece of cargo can be safely transported from origin to destination. Pre-planning: The shippers of the cargo should provide the master, or representative of the carrier, with information about the cargo so that the stowage and securing can be properly planned in advance. Stowage planning: When details of the base-structure or cradles is known, a suitable stowage location can be chosen and suitable bedding material can be ordered. Cradles and cribbage supports Some items of cargo comprise a main body and an extension piece or overhanging section that is separate from and is not wholly supported by the main body. Those extending parts must be properly and adequately held and supported to avoid damage being sustained by the parts as a result of movement during the voyage. Such support structures are often referred to as cradles or cribbage supports. Such structures should be thoughtfully planned and properly constructed, usually of either timber or steel with adequate and appropriate packing materials. Securing planning When the detail of a piece of heavy-lift or project cargo is known, calculations can be carried out to determine how many lashings are required to secure the cargo adequately against movement. Also, the required distribution of those lashings can be assessed. Loading and discharge operations When all of the pre-planning has been completed, information with regard to the items of cargo obtained, stowage location decided upon and method of securing planned and checked by calculations, consideration needs to be given to the loading operation. On board a ship that often carries heavy-lift items or project cargoes, either as part of the ISM procedures or within the Cargo Securing Manual, there might be a checklist to be completed when a heavy or awkward piece of cargo is to be loaded. The ship’s checklist should be used to ensure the completion of a safe loading operation and a safe discharge operation. Sea Fastenings For the securing of some items of cargo, such as transformers, tanks and heavy pieces of machinery, it might be appropriate to fit some sea fastenings and/or timber shores in addition to, and to complement lashings of chain or wire Some items of project-type cargo, such as concrete structures and flat-sided tanks, might have no lashing points and no means of applying lashings to the item of cargo itself. Such items might be adequately secured by the use of sea fastenings and/or timber shores alone. Sea fastenings, sometimes referred to as dogs, are lengths of steel section, for example I- beam, which are welded to the deck plating or tank-top hard against the base-structure of the item of cargo or with a small clearance to allow the fitting of timber wedges or blocks. CONTAINERS – ON AND UNDER DECK – CONTAINER AND NON-CONTAINER SHIPS Containers can be successfully carried on board ships designed and fitted for their carriage and on board other ships provided there are suitable lashings and fittings for the safe stowage and securing of the containers Containers are mostly either 20 ft (6.1 m) or 40 ft (12.2 m) long with heights ranging from 8 ft (2.4 m) to 9 ft 6 in (2.9 m), but all are of a standard width of 8 ft (2.4 m). It should be remembered that containers are not solid boxes of huge strength that can be stowed on board with little care or concern for either the container or its contents. They are, in fact, of fragile construction except for their corner- posts and base-support structure, and they must be stowed, secured and cared for properly and appropriately bearing in mind the type of ship upon which they are carried and the cargo stowed inside.  Non-container ships Containers can be carried by ships that are not container ships, but special attention should be given to the stowage and securing of the containers. Non-container ships can be divided into two types, those which are fitted with container-securing devices and those that have none. The CSS Code gives some guidance for the stowage and securing of containers on the decks of ships that are not specifically designed and fitted for containers. Container ships Every container ship has a securing system that was designed for the particular ship or ship type. Details of the system, arrangements for a variety of combinations of containers in stowage and the limits of the system will be set out in the approved Cargo Securing Manual. The design of the securing system will take into account the forces that act on the container. Voyage Any voyage can be divided into three main sections so far as the planning of things, and the checking for departures from those plans, is concerned. These sections are loading and securing passage planning actions during the voyage. LOADING AND SECURING The loading and securing of items of cargo must be carefully planned before operations begin and carried out in accordance with that plan, although some necessary adjustments to the plan might become apparent during the operations. PASSAGE PLANNING Passage planning is the term used for the planning of the route from the load port to the discharge port and the setting of courses and laying them on the appropriate charts. Passage planning also involves the consideration of weather and sea conditions likely to be encountered during the voyage because those conditions will affect the cargo.  Cargo spaces, like any other enclosed spaces, might suffer from oxygen depletion. Proper entry-into-enclosed-space precautions and procedures should always be followed before persons enter a cargo space.