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Tank Cleaning Operations on Chemical Tankers. Why Waste Money?

18 Jan 2019, by Informa Connect Insights

The expectations required of ship managers are becoming more and more challenging these days. Ballas Water Management, Scrubbers among others, are causing significant impact to the budget of vessels.

In the past years I have been involved in innumerable tank cleaning operations including optimising tank cleaning processes. It was interesting to observe that even sister vessels were using different schedules and methods for the same tank cleaning operation (cleaning from/to). So, what were the reasons?

  • Standard tank cleaning procedures are not always available on board, resulting in different tank cleaning procedures for the same task. Tank cleaning efficacy is highly correlated with the experience and professionalism of the officers on board the vessels.
  • Different tank cleaning additives (chemicals) with different efficiency are supplied to the vessels. Sometimes additives have been ordered by the company, other times by the charterers.
  • When testing the tank (for example performing a Wall Wash Test) some Chief Officers where not convinced that the tank was clean enough for the standard required and added additional tank cleaning operations (although the tank was clean enough).

The solution for saving time and money during tank cleaning operations is simple.

  • An industry tank cleaning guide (for example the Miracle Tank Cleaning Guide or Dr. Verweys) could be used for benchmarking the time and efficiency of the tank cleaning operations. Same could be supplied to the vessels for a minimum standard available. In addition, and in-house tank cleaning database will support the efficiency.
  • The choice of the correct tank cleaning additive (when required) is important. Often enough the additives are ordered according to the unit price rather than taking the total cost and the efficiency into consideration. This can result in excessive cost for tank cleaning additives as well as problems with the efficiency. Additive orders could take into consideration the experience of the officers rather than the unit price only.
  • A robust process to verify if the cargo tank system is clean according to the required standard is important. Usually this will be performed by using a wall wash test for chlorides, hydrocarbon or other relevant tests. These tests are often used by the cargo tank surveyors as well. Unfortunately, the standardised process is hardly complied with and therefore not always representative. In addition, this test will cover only a very small part of the tank and not the entire cargo tank system. For some years, wash water analyses have been available on the market and become increasingly popular. Although there are some limitations, this test is much more accurate and can easily avoid overcleaning.
  • The crewing has changed during the last years. The promotion to a Chief Officer or Master took a long time in the past enabling them to gain the relevant experience. Today the promotion is much faster and therefore the experience needs to be replaced by the relevant training.
  • The rejection of a cargo tank by a surveyor does not always indicate that the cargo tank is not clean enough for the relevant standard required.

Taking all the above into consideration, it is easy to calculate the savings when optimizing the tank cleaning operations.

  • One-hour time saving a year on a chemical tanker will pay off the cost for an industry tank cleaning guide.
  • One-day time saving a year on a chemical tanker can pay off a training course of an officer on board.
  • Using the correct tank cleaning additives can pay off a training course of all officers on board.

Apart from this, it should be taken into consideration that reducing the energy for tank cleaning will also reduce the overall emissions of the tanker.


Axel Kahl
Chemical Marine


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