What is deck cargo
It is a cargo exposed to the elements and is subject to sea, spray and wind, as well as the additional risk of
being washed or falling overboard.
Deck cargo main considerations
Contractual/legal requirements
Prior to carrying goods on deck, the owner/carrier should be fully
satisfied that it is safe to carry such goods on deck. If not, by carrying
goods on deck, the owner/carrier may be in breach of the contract of
carriage and its P&I cover may be prejudiced.
Deck cargo main considerations
Weather
Protection from the elements is another major concern in carriage of
cargoes on deck. As the cargo on deck would be exposed to sea water,
winds and sun, their combined effect is likely to cause damage to the
cargo.
Deck cargoes must therefore be carried in appropriate packaging units,
suppliers instructions should be strictly followed and additional
protective measures such as covering them with water and weather
proof covers (tarpaulin).
Deck cargo main considerations
Access
Through and unencumbered access on deck must be provided for the
crew to carry out their normal duties and in emergencies. Deck house
water-tight doors, ventilators on deck and other hatch and store
accesses must not be blocked by cargo or lashing.
As required by the Merchant shipping (health and safety at work)
regulations 1997.
Deck cargo main considerations
Stability
Deck cargoes can cause stability issues as they generally cause loss of GM due
to their high KG (centre of gravity relative to the ship)
Stability is adversely affected whilst loading also from own ships’ gear. Loading
from either side would cause a list towards the load and loss of GM.
The list and loss of GM is at its maximum at the instant the load is picked up as
the load is furthest transversely from the centre of the vessel and the effect of
the load is at the derrick head which needs to be taken into account when
determining ship stability for the operation. It will cause stresses on the ship’s
structural parts which need to be addressed.
Deck cargo main considerations
Handling, stowing and securing
- Containers and heavy items should be stowed in the fore and aft direction
- Cargo should be secured with suitable lashings to approved securing points
- Lashings should be evenly distributed
- Where necessary dunnage can be used to fill spaces to prevent shifting, and
provide additional friction between the cargo and deck - Portable tanks should either be full or empty so as to limit free surface
effect - Stowage should be properly supervised and regular inspections should be
made throughout the voyage - All crew should be wearing proper PPE
Deck cargo main considerations
Stability and structural strength of deck
Deck cargoes also cause potential structural strength issues as deck plates are
designed to withstand a maximum weight per square area, and must not be
overloaded.
Laying down appropriate dunnage to evenly distribute the weight on deck
before the cargo is loaded on it will ensure that no section of the deck plates is
adversely affected.
Deck cargo main considerations
Windage
Deck cargoes also result in increasing the exposed windage area which will
cause increased heeling from winds, particularly from beam winds which
would result in increased heeling couple
Heave motion
Up and down vertically
Surge motion
Bow going down
Sway motion
Port to Starboard motion
Yaw movement
a side-to side movement of the bow and stern of the ship.
Pitch movement of ship
Up and down horizontally
Roll movement
Tilt- more extreme than yaw
A ship has _ degrees of freedom of movement.
6
A ship has six degrees of freedom of movement.
These movements result in a combination of ________ _______ and __________ forces.
longitudinal, transverse and vertical forces
What needs to be taken into account when planning the loading of any cargo, and particularly a deck cargo.
longitudinal, transverse and vertical forces of the ship
how to minimise force of acceleration
Stow as close to mid-ships (and as low) as is
practicable;
* Ensure that the vessel will have adequate, but
not excessive metacentric height (GM)
throughout the voyage;
* Be prepared to reduce speed and/or alter
course;
* Take special care with weather routing;
* Do not rely on anti-rolling devices
SOLAS VI > Regulation 5 -
Stowage and Securing
6 All cargoes, other than solid and liquid
bulk cargoes, cargo units and cargo
transport units, shall be loaded, stowed
and secured throughout the voyage in
accordance with the Cargo Securing
Manual approved by the Administration.
SOLAS VII > Regulation 5 - Regulation 5 - Cargo Securing Manual
Cargo, cargo units and cargo
transport units shall be loaded,
stowed and secured throughout the
voyage in accordance with the Cargo
Securing Manual approved by the
Administration.
In the UK, the law which regulates the carriage of cargo is
The Merchant Shipping (Carriage of
Cargoes) Regulations 1999.
It is a requirement under this law, The Merchant Shipping (Carriage of Cargoes) Regulations 1999, that a ship-specific and approved ‘Cargo Securing Manual’
be carried on board, and:
- (a) Cargo and cargo units carried on or under deck are loaded, stowed and secured so as to
prevent as far as is practicable, throughout the voyage, damage or hazard to the ship and
the persons on board, and loss of cargo overboard; - (b) Appropriate precautions are taken during loading and transport of heavy cargoes or
cargoes with abnormal physical dimensions to ensure that no structural damage to the ship
occurs and to maintain adequate stability throughout the voyage; - (c) Cargo on board all ships to which regulation 5(4) is applicable shall be stowed and
secured throughout any voyage in accordance with the Cargo Securing Manual;
CSM
Cargo Securing Manual
CSMs are ship specific
CSM contents:
- Locations of safe access
- Cargo securing devices and
arrangements - Safe stowage ad securing
arrangements - Special measures of vessel or the
cargo
