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answered Jul 13, 2014 by ekwuemesam (3,660 points)
Ballast tanks should not be permanently inerted. It should include blasting and renewal of the coating systems in the ballast tanks as required by the required specification.  It is generally believed that the blasting and renewal of coating systems is sufficient to achieve the standard 25 year design life.
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answered Oct 28, 2014 by aodai (1,960 points)

Flanged connections should be provided in the Ballast tanks for inerting/purging the tanks via flexible hoses in the event of cargo leakage through the tank bulkhead. 

Following are the disadvantages with regard to having permanent Inert Gas Blanketing of Ballast tanks.

  • The additional independent Inerting and vent headers required for the ballast tanks would increase the amount of piping and interlocked valves on deck resulting in a congested deck space.
  • The escape route is generally routed via the tank tops of the Ballast tanks. Therefore having permanent Inert Gas piping and valves will complicate the design of escape routes.
  • Additional Inert gas generation system (Blowers, Scrubbers, Deck seal) might have to be installed to serve the Ballast tanks Inerting, which require additional space in the already congested Engine room and Main deck. 

 

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answered Oct 29, 2014 by belmoreno (2,190 points)

As it was said that Ballast tanks should not be permanently inerted; however, the followings need to be in place to ensure smooth operations.

  • A dehumidification system shoud be provided to dry ballast tanks in order to keep them dry when they are not in use.  Ballast tanks shoud be dehumidified and kept dry as much as possible to minimize corrosion for the design life.
  • Operating loading procedures shoud be written to minimize the use of seawater ballast. Stability and strength parameters with regard to the hull can be effectively managed under normal operating conditions by managing the residual cargo retained on board.  
  • Ballast tanks shoud remain available for ballasting operations at all times. The  tanks shoud remain connected to the ballast system and can be used in emergency/process upset situations as and when required.
  • Ballast tanks shoud still be required blasted and recoated.

 

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answered Nov 23, 2015 by Deepwater pilot (142 points)
Inerting ballast tanks while not common is actually done on some vessels.  If there is a leak between the cargo and ballast tank, the ballast tank would already be inerted and the ballast tank that is inerted rusts less.  It requires a double scrubber.  Google interting ballast tanks and the article is from Hellespont.
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