Where do you check coolant level when the RB-M 45 is underway?

When checking the coolant level on the RB-M 45 while underway, the appropriate location is in the recovery tank. The recovery tank is designed to provide a reserve of coolant, allowing for any expansion due to engine heat and ensuring sufficient coolant is available in the system. This tank is typically visible and accessible, making it a practical choice for monitoring coolant levels during operation.

In contrast, other areas such as the sea chest or expansion tank may not provide accurate readings when the vessel is in motion. The sea chest is primarily related to intake for cooling systems and not designed for coolant level checks. While the expansion tank does contain coolant, the recovery tank is specifically the point where you can ensure there's enough fluid available for the engine to operate efficiently and safely. Checking at the bridge would not provide any meaningful information about the coolant level. Thus, monitoring the recovery tank is essential for maintaining proper engine operation and preventing overheating.