In my last post How To Conduct Bunker Survey, I have explained the general step for Bunker Survey conducts. Now, the topic is about the way to calculate ship bunker that we have found on the ship tanks. It is suggested to read the last post to become familiar with calculation.
Bunker Survey
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 @15C,
- 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 degrees celcius, Density @ 15 C = 0.9870.
Tank Volume at Sounding 3.20 M = 157.20 Cubic Meter, at Sounding 3.30 M = 163.60 Cubic Meter.
** 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 @ 15C 0.9903 at 34 C = 0.9870 (see the picture below you need to interpolate if any different numbers on both columns).
ASTM Table 54B
- T 56 (WCF) : Density @15C 0.9903 at 34 C = 0.9892 (Quick formula with reducing factor for WCF is Density @ 15C – 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.
Tank Sounding
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.
Just drop your comments around this topic.
Regards,
Surveyors
Sumber berita dan gambar : sevensurveyor.com
