Compatibility of fuel is easily checked on board ship to insure that serious problems do not result. What statement concerning fuel incompatibility is true?

Correct Answer: Option A — Incompatible fuels, if allowed to mix, have a tendency to form sludge, and therefore must not be blended.

Incompatible fuels, often due to differing aromaticity or asphaltene content, will precipitate sludge when mixed. This sludge can rapidly clog fuel filters and separators, leading to engine failure. Good marine practice dictates that fuels from different sources must be tested for compatibility before being blended in storage tanks.