Question 39 OSE02 - Assistant Engineer - OSV

The Correct Answer is B **Explanation for Option B (Treating with carbon penetrating solvent):** Option B, "Treating with carbon penetrating solvent," is the most effective and standard technique used in conjunction with mechanical cleaning (wire brushing and scraping) to remove hard carbon deposits from diesel exhaust systems. These specialized solvents are formulated to break down, penetrate, and soften the tenacious chemical bonds of hard, baked-on carbon (soot) deposits, making them significantly easier and faster to remove mechanically. This preparatory step reduces the effort and potential damage associated with aggressive scraping. **Explanation of Incorrect Options:** * **A) Baking off carbon with heat lamps:** While extremely high heat (like that achieved during engine regeneration cycles or specialized furnace cleaning) can sometimes convert or break down carbon, using standard heat lamps is generally ineffective for deeply embedded, hard carbon deposits on large exhaust components. Furthermore, it is an impractical and potentially hazardous method for cleaning components on a boat. * **C) Treating with carbon tetrachloride solvent:** Carbon tetrachloride is a highly toxic, carcinogenic chemical. Its use has been severely restricted or banned in many maritime and industrial settings due to extreme health and environmental hazards. Although it is a solvent, it would not be a safe or permissible cleaning agent on a supply boat. * **D) Sand blasting with diamond dust:** Sand blasting (abrasive blasting) is a mechanical cleaning technique, but using diamond dust is prohibitively expensive and unnecessary for soot removal. More importantly, abrasive blasting is typically avoided for internal engine or exhaust components on working boats because the abrasive media can leave residue, damage finely machined surfaces, or clog downstream components (like catalytic converters or mufflers), leading to severe engine damage upon startup.