Fuel consumption onboard is influenced on several factors but most crucial is ship operation mode and fuel type in use. Conventual fuel preparation process onboard consists of several stages. One of the most essential processes is centrifugal separation treatment operation onboard, which consists of introducing fuel into the field of high centrifugal field, where impurities and sediments are separated from fuels. The quantity of separated sediments and impurities from the fuel is essential for accurate calculating the remaining fuel quantity on board (ROB). The purpose of this paper is to determine and verify the influence of potential factors that can affect the quantity of fuel consumption and separated sediments quantity from the fuel based on actual data from real product/chemical tanker powered by conventional fuels. By means of statistical analysis the average values, minimums, maximums, standard deviations, and variations, median and modes, standard errors for separated sludge from fuel, heavy fuel consumption (HSHFO) and diesel fuel consumption (LSMGO) during entire observed period and during specific operations modes are obtained. Furthermore, regression formulas between separated sediments from fuel vs fuel consumption during each ship operation mode are generated. Finally, by means of single and multifactorial analysis significant influence of ship operations mode on fuel consumption and separated quantity has been confirmed. This research contributed to find relations more accurately between separated sediments quantity to fuel consumption that might be used for more accurate emission calculation.