Steamship Mutual published a risk alert aiming to highlight some of the different types of incidents and provide consideration of likely contributory causes.
As Nahush Paranjpye, Loss Prevention, Steamship Mutual, reports, these, and past incidents, have influenced campaigns by various agencies to make sure that there is some measure of control in place to verify the cargo loading, distribution and securing arrangements on container ships.
Simply put, when a container ship is at sea there are forcesacting in the longitudinal, transverse and vertical axes of the ship and consequently these forces are also acting on the cargo on board
says Mr. Paranjpye.
For this reason, the Cargo Securing Manual (CSM) aims to ensure that cargo transport units carried on or under deck are loaded, stowed and secured adequately. This aspires to prevent any damage or hazard to the ship and the persons on board, and any damage or loss of the cargo.
What is more, Steamship notes that container vessels use class approved loading software that considers the vessels’ stability information and the distribution of cargo to evaluate the adequacy of lashing and securing arrangements in relation to the stowage and stability condition.
Each cargo container, unless empty, is affected by the nature of the cargo and the manner of securing the cargo
inside the container. This will in turn influence how the containers interact with adjacent containers and the overall behaviour of the stack
Steamship explains.
What is more, strength, condition and application of securing gear, together with strength, condition and availability of strong points on the vessel, will be further influenced by the motion and vibrations of the vessel.
It should be remembered that the container itself forms an integral part of the composite structure created as a result of the stowage and securing plan. The structural integrity of the container is, therefore, also of great importance to the overall integrity of the lashing system – the container should not form the weak-link in the overall lashing plan
highlights Mr. Mr. Paranjpye.
Some broad considerations when planning effective stowage and securing are:
Container fitness
While being loaded or when stowed at a high tier it may not be possible for the ship’s crew to perform a close-up inspection of every container. However, even from a distance, visually conspicuous conditions that might indicate potential issues should be discernible.
Visual monitoring could pre-empt risks because of:
- Structural damage to container frame (including corner posts, cross members, top/bottom/side/end rails, corner fittings, forklift pockets);
- Visible signs of significant corrosion / deterioration in plate thickness of strength members;
- Side/back wall panels – bulged, torn, temporary patches or other signs such as leaks, spills that may be indicative of a structural failure or poor stuffing and securing of cargo within the container.
Cargo stowage and securing
- Stack load / Maximum load (tank-top/hatch cover/deck plate);
- Load distribution / Centre of gravity;
- Windage area / Wind load / Pyramid stack;
- Streamlined vs unbalanced cargo distribution – Stack interactions / Isolated Tall Stacks / Exposed Stacks / Heavy over light;
- Stack weight;
- Racking stress;
- Securing arrangements – sufficient availability;
- Correct application of lashings (such as following the lashing plan correctly, position and tightness of turnbuckle check nuts, proper rigging (no overloading of securing points);
- Lashing patterns and wind lashing.
Stability condition
- Metacentric height (GM);
- Roll period;
- Deadweight / Draught / Trim / Propeller immersion.
Voyage planning
- Forecast;
- Weather routeing and Passage planning;
- Allowances for environmental conditions such as ice accretion;
- Effects of Speed, motion, vibrations & accelerations.
EXPLORE MORE ON STEAMSHIP’S TIPS FOR CONTAINERISED CARGO
