Putting new cargoes to the test

Not every ship is suited to carrying every cargo type

By Capt Akshat Arora

The exceptionally high demand for container shipments has prompted charterers to explore the possibility of utilising vessels not designed for this purpose, particularly bulk carriers.

However, before agreeing to carry containers on deck and/or inside holds on bulk carriers, it is imperative that a detailed suitability assessment is carried out to ensure that the containerised cargo can be safely loaded, carried and discharged from the vessel.

It is essential that statutory and safety requirements are identified, and approval is sought from the ship’s flag State and class society before commencing the trade. Additionally, as the carriage of containers onboard bulk carriers may constitute a material change of risk, it is essential to notify insurers in advance to prevent the risk of cover being prejudiced.

To mitigate the risks involved with the carriage of containers on a ship not designed for this purpose, a non- exhaustive list of recommendations is highlighted below, which should be taken into consideration while carrying out the risk assessments.

  • Check with the class society if the ship’s certificates/documents will require revision and re-approval. These include, but are not limited to:
  • Class certificate
  • Loading computer/stability manuals
  • Cargo securing manual
  • Dynamic lashing forces calculation software
  • Dangerous Goods (DG) certificate
  • Carry out an assessment of the tank top and hatch cover structural strength to ensure that the weight of the stacking containers does not exceed the permissible load. Appropriate measures, like dunnage, may need to be used to distribute the container point loads uniformly and to safely optimise the stack weight distribution. All calculations related to the adequacy of the structural strength would depend on accuracy of the verified gross mass (VGM) of the containers.
  • Carry out dynamic stress and stability calculations with due regard to the windage area for containers stowed above deck. These calculations (departure and arrival port conditions) should be reviewed by the class society.
  • Check the strength, condition and application of securing gear and securing points on the vessel. This includes checking and verification of the physical condition of welds made for seafastening purposes.
  • Carry out dynamic lashing calculations. Be mindful of the ship’s metacentric height (GM) – the higher the GM value, the bigger the acceleration forces in securing gear. These calculations should be reviewed by the class society.
  • Ensure that blind sectors are appropriately addressed in master’s standing orders, taking into account on- deck containers.
  • If the proposed carriage includes carrying reefer containers, consider the provision of power supply with due regard to additional load on the generators.
  • Any DG cargo should not be carried unless the class society has issued a certificate that allows loading of the intended DG cargoes. If the ship is going to load DG cargoes inside cargo hold, it is required to confirm the provisions of firefighting onboard. Attention is drawn to SOLAS II-2/10.7.1, whereby, as required and for ships > 2,000 GT, with or without dangerous goods, cargo holds shall be protected by a fixed fire extinguishing system. If the ship is going to load DG cargoes on or above weather deck, the ship should be provided with a water-mist lance in accordance with SOLAS II-2/10.7.3.
  • Ensure a detailed KYC (know-your- customer) process is in place for the cargo booking and that the shipper is properly vetted to avoid any risk of mis- or undeclared DG cargoes.
  • Review and revise the company procedures in accordance with the ISM code to cover the risks posed by containerised cargoes.
  • Ensure that the master and crew are trained and familiarised with the risks involved with carriage of containerised cargo. This includes awareness of the parametric rolling motion phenomenon and actions to be taken to avoid such a situation.
  • Subscribe to a weather routing service during the voyage. The ship’s passage plan should address the maximum safe wave height and weather conditions together with advice from the charter party or weather routing service. Subject to weather conditions, the cargo lashings should be regularly checked and tightened during the voyage by the crew.
  • The torsional movement may cause deformation of hatch cover panels and associated fittings. Carry out a weathertightness test of the hatch covers after discharging containers and prior to carriage of a dry bulk cargo.
  • Lastly, it is advisable to have a Marine Warranty Survey (MWS) carried out at the load port to assess the vessel’s suitability for the intended loading, and to ensure that the risks associated with the specific operation are reduced to an acceptable level in accordance with industry best practice.

Capt Akshat Arora is senior surveyor for loss prevention at The Standard Club.