Question 18 OSE02 - Assistant Engineer - OSV

The Correct Answer is B. **Explanation for Option B (Daily):** Moisture (condensed water vapor) naturally accumulates in compressed air systems used for starting diesel engines, especially in the humid and variable temperature environment experienced by an offshore supply vessel. This moisture, if not removed, can cause corrosion, damage air starting motors (vane erosion, rusting bearings), and potentially freeze or block air passages. Standard maritime and engineering best practice dictates that manually draining moisture separators (or air receivers/bottles) should be performed at least once per 24-hour period (daily) to maintain the integrity and reliability of the critical engine starting system. This frequency ensures that the majority of accumulated condensate is removed regularly. **Explanation of Why Other Options Are Incorrect:** * **A) Hourly:** While draining hourly would maximize moisture removal, it is overly frequent and labor-intensive for a standard operational checklist item, especially when the system components (like air receivers) have significant capacity. Daily draining is generally sufficient for preventative maintenance in this context. * **C) Weekly:** Draining only weekly is insufficient. Over a week, a significant volume of water can accumulate, posing a high risk of system corrosion, contamination, and potential failure or damage to the air starting motors before the scheduled drain time. * **D) Monthly:** Monthly draining is completely unacceptable for compressed air systems in a marine environment. High accumulation of corrosive condensate over such a long period would guarantee system damage and significantly compromise the reliability of the main and auxiliary engine starting mechanism.