Bunkers come in a wide variety of quality, levels and are blended in various ways to meet the ISO specification 8217. Various blend components can keep heavy material in suspension that could precipitate out over time or when mixed with dissimilar bunker fuels. These heavy particulates can fall out of suspension and cause heavy sludge generation in the purifier. For this reason, good onboard bunker fuel management is essential. 
 
Before ordering bunkers, each ship should use the bunker worksheet to calculate the expected bunker consumption and verify the amount with the appropriate Voyage Manager. A copy of the final agreed-upon bunker nomination should be sent to the company. 
 
As a minimum, vessels should have enough onboard to complete the current voyage maintaining the