cargo stowage inspection
Due to variations in physical properties segregation is essential to prevent contamination and damage of commodities.
Segregation is also done to provide easy access during discharge and on-board emergencies.
This process is excelled only through knowledge and experience unless certain specifications of the shippers have to be adhered to.
COMPATIBILITY WITH OTHER COMMODITIES AND OTHER FACTORS FOR SEGREGATION
Cargoes that cause contamination to one another should, obviously not be stored together.
For example the storage of bales of wet hides above food stuff on a tween deck is not recommended, as leakage of pickling fluid of the wet hides through the scuppers and into the hold bilge could result in formation of vapours and contamination of the susceptible food stuff stowage.
Also segregation is essential for those cargoes liable to damages due to heat and must be stored away from engine rooms and ship tanks that require heat during voyage.
cargo stowage inspection -Over-stow of Cargo
Items of cargo that becomes ‘buried’ under cargo for another port and are thus inaccessible at the nominated port of discharge.
Thus cargo has to be shifted in order to gain access at the nominated port.
Over stows intentionally occur through no choice of the ship’s officer in cases where space is at a premium.
over stowage cargo is indicated in the stowage plan by:
1. Water based paint.
2. Water proof marking pens.
3.1.Layers of timber (dunnage)
3.2. Hessian cloth.
3.3. Plastic sheeting.
cargo stowage inspection -Dunnage
Dunnage is the term used to describe any material that is used to assist in creating a good stow for cargo.
It is of two types:
FUNCTIONS OF DUNNAGE
Protection: Dunnage protects cargo from water in bilges and water from tween deck scuppers. Leakage from tanks, ship sweat and leakages from adjacent cargo.
Ventilation: Airways such as ducts are provided by dunnage to maintain fresh air flow.
Support: Dunnage provides stow with strength and support and prevents the cargo from chafing against structural members of the ship such as pillars and frames.
Security: In certain countries the security system itself is corrupt, therefore dunnage provides certain degree of security by hiding the view of items in stowage.
Spar ceiling and tank top ceiling
Spar ceiling is fitted to prevent items of the cargo from making direct contact with the ship shell plating, it is often removed during loading and unloading to prevent damage.
Tank top ceiling consists of lengths of stout timber secured to the tank top of the lower hold, to prevent damage of the steelwork on the tank top.
Temporary dunnage is available in various sizes, usually between 2ft x 2ft to 4ft x 4ft with length ranging from 6ft to 8ft. The material used is often pine wood.
The main function of temporary dunnage is cargo segregation and to secure them, but it does not permit air flow and must be used in conjunction with square dunnage for drainage and ventilation.
APPLICATION AND RELEVANCE OF DUNNAGE
Factors that lead to damage of cargoes are:
1. Crushing in stow.
3. Direct contact with vessel structure.
4. Lack of ventilation.
The use of dunnage eliminates these factors.
cargo stowage inspection -Lashing and Securing
The general rule of lashing for single items of cargo is that the minimum breaking load of the lashings should not be less than twice the static load of item being secured.
A well-established ‘rule of the thumb’ as used by seafarers is:
‘The safe working load of total lashings must be equal three times the static weight of item being lashed’.
Therefore the total holding power of lashings holding a cargo item vertically downward should be three times the static weight of the item in tonnes.
To prevent transverse movement of cargo the lashing should be seven-tenths of vertical holding power.
To prevent fore and aft movement , the holding power must be three-tenths of the vertical holding power.
CARGO STOWAGE’S Article by Akshay Pradeep