Bunker Survey Calculation



marine cargo ship surveyors

The bunker calculation is simple and needs the following:
– Tank Sounding data and Tank Capacity Table. The Corrected Sounding means below is the sounding after correcting with vessel’s trim and list.
– Temperature of Oil on Tanks,
– Oil Density @15*C,
– Table ASTM 54B (VCF) and Table ASTM 56 (WCF).

Now we could go with sample of 1 tank to test the calculation.

** Question :
FO Tank No. 1 Center, Corrected Sounding = 3.27 Meter,
Temperature = 34*C,and density @ 15*C = 0.9903 (given density).
Tank Volume at Sounding 3.20 M = 157.20 Cubic Meter,
at Sounding 3.30 M = 163.60 Cubic Meter.

Table 54B

** Answer :
– The Quantity in Metric Ton = Oil Vol x VCF x WCF,
– Observe Volume = {(3.27 – 3.20) / (3.30 – 3.20) x (163.60 – 157.20)} + 157.20
= (0.07/0.10) x (6.40) + 157.20 = 4.48 + 157.20 = 161.68 Cu.M.
– T 54B (VCF) > Density @ 15*C 0.9903 = 0.9870 (see the above picture you need to interpolate if any different numbers on both columns).
ASTM Table 54B – T 56 (WCF) : Density @15*C 0.9903 = 0.9892
(Quick formula with reducing factor for WCF is Density @ 15*C – 0.0011 = 0.9903 – 0.0011 = 0.9892).
We don’t need to see the table anymore.
– So, The Quantity in MT is 161.68 x 0.9870 x 0.9892 = 157.85 MT.

Sample calculation tanks sounding attached below (the Temp below should be 34 C).
Marine and Cargo Surveyors Webblog

Note : If you do calculation with Volume in Barrel,  just uses ASTM Table 6B for VCF, ASTM Table 11 for WCF in Long Ton and then ASTM Table 13 for WCF in Metric Ton.

For the above calculation, you could download the software BunkerCal by follow this link http://www.sevensurveyor.com/software/bunker-calculation/

Just drop your comments around this topic.

Regards,
Surveyors



Author: Faisal Yusuf

Hi, my name is Faisal Yusuf, but you can call me Surveyor. I live in Jakarta, Indonesia and work as a surveyor.

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