Tank Calibration - Sounding & Ullage Tables

Tank Volume Calculations for each level and angle of trim / heel

   Eventually you have visited this page because you face operational or commercial problems due to erroneous Calibration Tables of a specific ship. Many vessels face this problem since their Capacity Plan and Tank Calibration Tables are stamped by the Classification societies only for the information they include, but have never been approved because classes focus on vessel's safety and technical issues but not on commercial ones.

  No mater the shape of the tank, we can prepare accurate calibration tables using our direct tank calculation software for any level, trim and list without the approximations and restrictions of the old style ullage corrections. Calibration tables can be prepared at any increment and format requested and are given in hard copy and electronic format. Optionally the calibration tables can be accompanied with our amcLiquid software for calulating volumes at any level, trim and list using only the ullage or sounding value.


Are the existing Calibration Tables correct?

  There are many reasons that calibration tables of a specific tank could be in error but the most frequently met are the following:

-   Sounding Pipe or Ullage Reference Point is considered at a different location from the place that is finally fitted. Many times the calibration tables are based on the preliminary drawings of the ship (prepared before construction) but some sounding pipes or ullage ports have been fitted at a different location due to technical obstructions at the studied location. Many cases have been resolved with an onboard survey determining the exact location of the sounding pipe or ullage reference point.

-   Calibration tables are correct when the ship is evenly loaded, but trim and list corrections are in error or not available. These corrections are of major importance in most of the cases for an accurate determination of the loaded quantity of bunkers or cargo. Many calibration tables use the method of correcting the gauged ullage or sounding. This method assumes the vessel evenly loaded in order to determine the correction to the ullage or sounding when the vessel is listed and could be in error when tank's top plating is partly wet or bottom plating is partly dry by it's content. Our direct calculation technique is based on fluid shifting within the tank and calculates the actual volume loaded in the tank without any corrections on the ullage or sounding value.

-   The calibration tables have been prepared with a software which is not capable of handling the case where tank's top plating is partly wet or bottom plating is partly dry by it's content. In many cases the tanks are modelled by means of some standard transverse sections but for the above case additional transverse sections are required in order to determine the extend that the top or bottom plating is partly wet or dry. Our software has the ability to dynamically reproduce additional sections when it is required and accurately determine the actual free surface of the liquid.

-   Tanks full capacity has changed due to a modification or is not accurately calculated. In this case, the Internal Electro-Optical Distance Ranging Method by laser scanning supported by our powerful software is required. This method is ideal for every ship but especially for floating storage vessels, delivery barges, chemical tankers, bunker tanks etc., where accuracy is very important.

  In order to obtain a more complete picture of how we can be of your assistance regarding this matter, please do not hesitate to contact this office for further information or to arrange a meeting.


 

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