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Safety precautions during ballasting / deballasting operation - bulk carriers recommended guide

Risk of pressing up ballast tanks

In a cargo damage case a vessel found pressed up its ballast tanks in order to optimise trim and to satisfy mandatory stability criteria. The operation resulted in the unexpected flooding of a cargo hold causing extensive damage to the cargo. The bulk carrier was carrying out ballast exchange operations mid voyage and pressed up one set of double bottom ballast tanks. On arrival it was observed that one of her holds had significant water inside and considerable damage to bottom stow cargo.



The vessel had opened up several manhole covers for routine inspection of her ballast tanks. After the incident it was noted that the high-level bilge alarms in the hold were not functioning. Careful investigation revealed poorly secured manhole covers are still a frequent cause of water ingress into holds, many, but not all, arising after drydocking where shore staff have not secured covers properly.

If double bottom manhole covers are removed for whatever purpose, it is recommended a note be made of where and when, this not only acts as an aide memoire but also helps in defending claims should water ingress occur. Good maintenance should also be in place, the manhole covers/gasket arrangement and like should be routinely checked, if not already included as part of the routine inspection/maintenance programme associated with the ship's ballast tanks. Hold high-level bilge alarms should be tested on a regular basis, logged and defects, if any, rectified immediately. (Source :UK P&I |Club)


Ship’s Safety

When planning and carrying out operations with ballast water the following factors must be taken into account:


The Ship’s course and speed is to be properly set depending on the prevailing weather conditions. Sufficient personnel must be available to allow the safe monitoring of the operation.


Personnel Safety

If tank entry is required to affect the taking of samples, carrying out a ballast tank inspection, or for manually removing solid sediments, then all the safety precautions of the Enclosed Space Entry Permit must be complied with.


Ballast Tank’s Venting System

It is of paramount importance that all segregated and permanent ballast tank vents are properly set up and in good condition prior to any ballast operation. All vent closures that are capable of manual operation must be in the open position. The original design venting capability must be available at all times.

The vents are to be further checked soon after starting the operation to confirm that the tanks are venting freely. Improperly set ballast vents can result in severe structural damage to the vessel.

Vent screens are to be kept free from paint as this can seriously reduce their volumetric capacity.

Great care is to be taken in conditions where icing is occurring. In certain circumstances screens on ballast tank vents can become blocked by icing. During ballast operations in such conditions, the responsible officer is to ensure that all precautions are adopted to ensure the free venting of ballast tanks, and that regular checks are made to ensure continuous free venting throughout the operation.


Cathodic protection

Uncoated clean ballast tanks have a sacrificial zinc anode system fitted to protect the entire tank structure. If loading ballast into tanks fitted with cathodic protection in a freshwater river or estuary, it is important to change the ballast at sea as soon as is practical, in order to achieve the full effect of the cathodic protection system.


Inspections

Ballast tanks must be inspected on a twelve-monthly basis and a report on the condition of the tank sent to the Management Office . More frequent inspections may be carried out if the tanks are in poor condition or if work has been carried out within the tank.

If it has been necessary to weld securing arrangements, such as pad eyes, onto the side plating of a cargo hold for the lashing of cargo, then the area behind the plating within the tank must be inspected and touched up with a suitable coating.


Check items

  1. proper, diligent and recorded ballast tank inspections must be carried out and form a part of the ship’s planned maintenance system
  2. ballast tank inspections should form the basis of a dry-docking defect list
  3. a proper system of inspections and checks must be carried out to assess the integrity of ballast tanks after hold cleaning and during the ballast voyage
  4. bulk carrier inspections should include all parts and areas where water ballast can get into cargo holds: bilge systems, manhole covers, and tank top and bulkhead welds
  5. proper guidance should be given to masters and officers with respect to cargo carriage and ballast water management
  6. advice and training should be given that pumping ballast can cause extreme pressures on the tank structures and fittings such as manhole lids, even when tanks are fitted with classapproved air vents. Consider only gravitating water ballast so as to reduce pressure on the tanks and manhole lids
  7. ship’s procedures should always include rigorous checks on the ship’s watertight integrity, including daily tank and bilge soundings, bilge alarm tests, checks on sounding pipe caps and inspections of spaces not often visited, including cofferdams and void spaces



Related guideline

  1. Ballast exchange procedure at sea


  2. Practical method for the control of transportation of harmful marine organisms


  3. Loading of high density cargo and water ballast distribution for bulk carriers


  4. Regulation of pumping system of bulk carriers


  5. Risk of partially filled ballast tanks


  6. Handling water ingress problems in bulk carrier, investigation and countermeasures

  7. Various categories of garbage and management onboard



Reference publications

  1. MARPOL 73/78
  2. IMO Resolution A.774 (18) – “Guidelines for Preventing the Introduction of Unwanted Aquatic Organisms and Pathogens from Ship’s Ballast Water and Sediment Discharged”
  3. Ship’s “Procedure and Arrangements manual” (Approved by Class)
  4. Guide to Port Entry
  5. US NPDES Vessel General Permit Compliance Manual
Our detail pages illustrated many safety aspects of Bulk carrier

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Operation of sea going bulk carriers involved numerous hazards . Careful planning and exercising due caution for all critical shipboard matters are important . This site is a quick reference to international shipping community with guidance and information on the loading and discharging of modern bulk carriers so as to remain within the limitations as specified by the classification society.
It is vital to reduce the likelihood of over-stressing the ship's structure and also complying with all essential safety measures for a safe passage at sea. Our detail pages contain various bulk carrier related topics that might be useful for people working on board and those who working ashore in the terminal. For any remarks please Contact us

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