Reefer containers proposed for stowage must be accompanied by a reefer manifest. This reefer manifest should contain information regarding Container No., Stow position, Commodity, Temperature and Ventilation status.
Stowage location of reefers must be checked against vessels reefer receptacle locations. In case reefer containers must be loaded in irregular locations, it must be confirmed that monitoring and repair will be possible during the voyage and that vessel has sufficient extension cables for providing power.
Reefer containers shall not be stowed on extreme outboard locations on deck.
It must be borne in mind that number of working reefer receptacles, extension cables and condition of auxiliary machinery (generators) available on board may limit the maximum number of reefer containers that the vessel can safely carry.
Carefully Check Stacking Weights in Containership cargo stowage and pre planning
Prior loading cargo, stacking weights of containers must be checked against the allowable stack weights on board the vessel both on deck and under deck. Neglecting above may cause serious damage to ships structure, hull and eventually overall stabilty of ship may get affected.
Maximum allowable stack weights of Tank tops, Hatch covers and Decks shall not be exceeded at any time.
If any stacks are found to be exceeding the allowable stack weights, Terminal planner / Central planner is to be informed and cargo stow plan appropriately modified.
In case such anomaly is noticed after containers have been loaded, the master shall notify all concerned parties and have the condition corrected at the earliest prior departure.
How to calculate Lashing Strength onboard container ships
Lashing strength of deck cargo shall be ascertained by using the appropriate lashing strength calculation software where provided.
All resulting values for lashing strength must be within the tolerance limits prescribed by vessels classification society.
Lashing strength calculation software provides alarms/highlights for containers that are affected by excessive forces. Such situation may be corrected by adjusting the vessels Ballast / Fuel condition or alternatively by advising Terminal planner / Central planner and having the cargo stow plan appropriately modified.
In case such anomaly is noticed, the master shall notify all concerned parties and have the condition corrected at the earliest prior departure or at the next port as instructed by Vessel operator / Central planner. In such case, master shall also take this special case into account during maneuvering in heavy weather.
If lashing strength calculation results are exceeding tolerance limits, failure of lashing gear or failure of the container itself may occur. Probability of this happening is highly enhanced in inclement weather and attendant heavy rolling, pitching or heaving.
Each lashing gear component has a safe working load and is likely to fail if forces exceed this value. Failure of lashing gear components will then besides freeing restraints, also likely result in forces on containers exceeding tolerance limits.
Sea freight containers are designed to withstand a defined minimum racking force, side wall racking force, vertical compression, vertical tension, corner post and shearing force at twist lock.
Forces exceeding these defined minimum values (tolerance limits) will likely result in structural damage or collapse of the container. If one container in a stack collapses, it is likely that the entire stack will collapse.
Particular caution is to be exercised when stowing dangerous cargo on board the vessel.
Any dangerous cargo presented for loading must be accompanied by a proper manifest and declaration as required by international regulations . Further this DG cargo must be acceptable for carriage as per IMDG code guidance. Reference here is made to the list of UN numbers restricted/prohibited for carriage on board particular vessels.
After confirming acceptability of the DG cargo, the plan must be checked for proper stowage and segregation. Although terminal and central planners should provide proper stow of DG cargo, the final responsibility always lies with the Master.
Reference shall be made to vessels Document of Compliance with special requirements for ships carrying dangerous goods for confirming that proposed DG classes are acceptable for stowage in planned locations on board.
Specific stowage requirements for DG cargo
(e.g. Clear of living quarters OR if under deck, in a mechanically ventilated space etc) may be verified from individual entries of dangerous goods list in the IMDG code.
DG segregation shall be verified for compliance with requirements of the IMDG code. Caution must be exercised when using vessels stowage planning software for this purpose as it may or may not have comprehensive means of checking for bad stowage & segregation against the latest international requirements. It is advisable to manually check for compliance.
Segregation requirements of the IMDG code and any other local/national regulations must be strictly adhered to. One must be aware that even DG cargoes belonging to the same class may have segregation requirements amongst them.
A good example is that of alkalis requiring to be separated form acids where as both acids and alkalis may belong to IMO Class 8. Such segregation requirement will not be found in the segregation tables of the IMDG code and only individual entries of the dangerous goods list in the code indicate the requirement.
Containership cargo stowage and planning - Preparation for Out of Gauge Container Stowage
Out of gauge containers are usually stowed underdeck and in case of an On Deck Stow, careful consideration will be required. Local planner or agent may be requested for such approval prior loading.
Hatch cover clearance and Cell guide clearance must be verified to confirm that there will be no damage to the vessel or cargo when loaded.
Appropriate number of slots must be kept vacant to accommodate the OOG cargo as necessary.
General guidance for Containership cargo stowage and planning - Special Container Stowage
When stowing high cube containers on deck, visibility from bridge must be considered in case several high cube containers are in the same stack.
When stowing these Under Deck, Hatch cover clearance must be considered.
Depending on the vessels construction, a slot may need to be kept vacant if more that 1 high cube container is loaded Under Deck.
The stowage of 45 foot containers is restricted by lashing requirements, lashing bridges, Reefer monitoring platforms or other obstructions.
Allowable positions for loading 45’ containers must be carefully checked prior loading.
Containership cargo stowage and planning - 20 feet or 40 feet or 45 feet Compulsory Stowage Locations
These stow positions are usually incorporated in the stowage planning software itself and errors will be indicated in case of violation. Do not override the stowage planning software manually to accommodate any inappropriate stow suggested by the terminal.
When stowing these Under Deck, Hatch cover clearance must be considered. Depending on the vessels construction, a slot may need to be kept vacant if it is necessary.
The stowage of 45 foot containers is restricted by lashing requirements, lashing bridges, Reefer monitoring platforms or other obstructions.
Allowable positions for loading 45 feet containers must be carefully checked prior loading.
Container ship cargo stowage and planning - Irregular Stowage of Containers
Stowage plan must be checked for any irregular stowage like those mentioned below or hanging boxes etc.
Stacking Weights
Lashing Strength
Special Container Stowage
Over-stow of Containers
Dangerous Cargo Stowage & Segregation
20 or 40 or 45 feet Compulsory Stowage Locations
Hatch Cover Clearance (High cube containers Under Deck )
Out of Gauge Container Stowage
Container ship cargo stowage and planning - Avoid overstow of Containers
The duty of the Terminal planner/ Central planner is to carefully plan the loading on board so as to ensure minimum or no overstow of containers that will require to be re-stowed at subsequent ports.
However same must be checked on board and if found, must be brought to the notice of the Terminal planner or Local agent for their information.
Container vessel cargo operations involve many complexities and careful consideration will need to be made for safe cargo handling and planning Summarized below are some basic principles. These procedures are only indicative, not exhaustive in nature and one must always be guided by practices of good seamanship.
Hatch Cover Clearance (High cube containers Under Deck ) Hatch cover clearance must be checked carefully in case of loading over height containers or high cube containers underdeck.
If any other irregularities are found in the stowage plan they must be corrected by liaising with Terminal planner / Central planner or local agent.
A good example would be an isolated tower of 4 or 5 high remaining on deck after all adjacent containers have been discharged. Such stowage, at Master’s discretion may need correction by shifting some containers of the tower down on deck or elsewhere.
Stowage location of reefers must be checked against vessels reefer receptacle locations. In case reefer containers must be loaded in irregular locations, it must be confirmed that monitoring and repair will be possible during the voyage and that vessel has sufficient extension cables for providing power.
Reefer containers shall not be stowed on extreme outboard locations on deck.
It must be borne in mind that number of working reefer receptacles, extension cables and condition of auxiliary machinery (generators) available on board may limit the maximum number of reefer containers that the vessel can safely carry.
• Stacking Weights
Carefully Check Stacking Weights in Containership cargo stowage and pre planning
Prior loading cargo, stacking weights of containers must be checked against the allowable stack weights on board the vessel both on deck and under deck. Neglecting above may cause serious damage to ships structure, hull and eventually overall stabilty of ship may get affected.
Maximum allowable stack weights of Tank tops, Hatch covers and Decks shall not be exceeded at any time.
If any stacks are found to be exceeding the allowable stack weights, Terminal planner / Central planner is to be informed and cargo stow plan appropriately modified.
In case such anomaly is noticed after containers have been loaded, the master shall notify all concerned parties and have the condition corrected at the earliest prior departure.
• Lashing strength
How to calculate Lashing Strength onboard container ships
Lashing strength of deck cargo shall be ascertained by using the appropriate lashing strength calculation software where provided.
All resulting values for lashing strength must be within the tolerance limits prescribed by vessels classification society.
Lashing strength calculation software provides alarms/highlights for containers that are affected by excessive forces. Such situation may be corrected by adjusting the vessels Ballast / Fuel condition or alternatively by advising Terminal planner / Central planner and having the cargo stow plan appropriately modified.
In case such anomaly is noticed, the master shall notify all concerned parties and have the condition corrected at the earliest prior departure or at the next port as instructed by Vessel operator / Central planner. In such case, master shall also take this special case into account during maneuvering in heavy weather.
If lashing strength calculation results are exceeding tolerance limits, failure of lashing gear or failure of the container itself may occur. Probability of this happening is highly enhanced in inclement weather and attendant heavy rolling, pitching or heaving.
Each lashing gear component has a safe working load and is likely to fail if forces exceed this value. Failure of lashing gear components will then besides freeing restraints, also likely result in forces on containers exceeding tolerance limits.
Sea freight containers are designed to withstand a defined minimum racking force, side wall racking force, vertical compression, vertical tension, corner post and shearing force at twist lock.
Forces exceeding these defined minimum values (tolerance limits) will likely result in structural damage or collapse of the container. If one container in a stack collapses, it is likely that the entire stack will collapse.
• Dangerous goods stowage and segregation
Particular caution is to be exercised when stowing dangerous cargo on board the vessel.
Any dangerous cargo presented for loading must be accompanied by a proper manifest and declaration as required by international regulations . Further this DG cargo must be acceptable for carriage as per IMDG code guidance. Reference here is made to the list of UN numbers restricted/prohibited for carriage on board particular vessels.
After confirming acceptability of the DG cargo, the plan must be checked for proper stowage and segregation. Although terminal and central planners should provide proper stow of DG cargo, the final responsibility always lies with the Master.
Reference shall be made to vessels Document of Compliance with special requirements for ships carrying dangerous goods for confirming that proposed DG classes are acceptable for stowage in planned locations on board.
Specific stowage requirements for DG cargo
(e.g. Clear of living quarters OR if under deck, in a mechanically ventilated space etc) may be verified from individual entries of dangerous goods list in the IMDG code.
DG segregation shall be verified for compliance with requirements of the IMDG code. Caution must be exercised when using vessels stowage planning software for this purpose as it may or may not have comprehensive means of checking for bad stowage & segregation against the latest international requirements. It is advisable to manually check for compliance.
Segregation requirements of the IMDG code and any other local/national regulations must be strictly adhered to. One must be aware that even DG cargoes belonging to the same class may have segregation requirements amongst them.
A good example is that of alkalis requiring to be separated form acids where as both acids and alkalis may belong to IMO Class 8. Such segregation requirement will not be found in the segregation tables of the IMDG code and only individual entries of the dangerous goods list in the code indicate the requirement.
• Out of Gauge Container Stowage
Containership cargo stowage and planning - Preparation for Out of Gauge Container Stowage
Out of gauge containers are usually stowed underdeck and in case of an On Deck Stow, careful consideration will be required. Local planner or agent may be requested for such approval prior loading.
Hatch cover clearance and Cell guide clearance must be verified to confirm that there will be no damage to the vessel or cargo when loaded.
Appropriate number of slots must be kept vacant to accommodate the OOG cargo as necessary.
• Special Container Stowage
General guidance for Containership cargo stowage and planning - Special Container Stowage
When stowing high cube containers on deck, visibility from bridge must be considered in case several high cube containers are in the same stack.
When stowing these Under Deck, Hatch cover clearance must be considered.
Depending on the vessels construction, a slot may need to be kept vacant if more that 1 high cube container is loaded Under Deck.
The stowage of 45 foot containers is restricted by lashing requirements, lashing bridges, Reefer monitoring platforms or other obstructions.
Allowable positions for loading 45’ containers must be carefully checked prior loading.
• 20’ or 40’ or 45’ Compulsory Stowage Locations
Containership cargo stowage and planning - 20 feet or 40 feet or 45 feet Compulsory Stowage Locations
These stow positions are usually incorporated in the stowage planning software itself and errors will be indicated in case of violation. Do not override the stowage planning software manually to accommodate any inappropriate stow suggested by the terminal.
When stowing these Under Deck, Hatch cover clearance must be considered. Depending on the vessels construction, a slot may need to be kept vacant if it is necessary.
The stowage of 45 foot containers is restricted by lashing requirements, lashing bridges, Reefer monitoring platforms or other obstructions.
Allowable positions for loading 45 feet containers must be carefully checked prior loading.
• Irregular Stowage of Containers
Container ship cargo stowage and planning - Irregular Stowage of Containers
Stowage plan must be checked for any irregular stowage like those mentioned below or hanging boxes etc.
Stacking Weights
Lashing Strength
Special Container Stowage
Over-stow of Containers
Dangerous Cargo Stowage & Segregation
20 or 40 or 45 feet Compulsory Stowage Locations
Hatch Cover Clearance (High cube containers Under Deck )
Out of Gauge Container Stowage
• Over-stow of Containers
Container ship cargo stowage and planning - Avoid overstow of Containers
The duty of the Terminal planner/ Central planner is to carefully plan the loading on board so as to ensure minimum or no overstow of containers that will require to be re-stowed at subsequent ports.
However same must be checked on board and if found, must be brought to the notice of the Terminal planner or Local agent for their information.
• Hatch Cover Clearance (High cube containers Under Deck ) Containership cargo stowage and planning
Container vessel cargo operations involve many complexities and careful consideration will need to be made for safe cargo handling and planning Summarized below are some basic principles. These procedures are only indicative, not exhaustive in nature and one must always be guided by practices of good seamanship.
containership cargo stowage
Hatch Cover Clearance (High cube containers Under Deck ) Hatch cover clearance must be checked carefully in case of loading over height containers or high cube containers underdeck.
• Other matters regarding cargo stowage as necessary Containership cargo stowage and planning - avoid isolated tower of containers remaining on deck
If any other irregularities are found in the stowage plan they must be corrected by liaising with Terminal planner / Central planner or local agent.
A good example would be an isolated tower of 4 or 5 high remaining on deck after all adjacent containers have been discharged. Such stowage, at Master’s discretion may need correction by shifting some containers of the tower down on deck or elsewhere.