BUNKER CALCULATION ONBOARD SHIPS

BUNKER CALCULATION
It has been observed that even for such a simple procedure much headache is being taken.
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
Commonly this is done prior to and after a time charter period than mentions as On Hire Bunker (prior) and Off Hire Bunker (after), the Bunker Survey is required to check the amount Bunker transferred or supplied onto the Ship’s Tanks. This job is associated with Ship’s Chief Engineer, the Person who responsible for bunker onboard.
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.
– The Quantity in Metric Ton = Oil Vol x VCF x WCF,
– Observe Volume = {(3.27 – 3.20) / (3.30 – 3.05) 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).
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.
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.