Question 69 RVR05 - Master of LT 100 GRT

The Correct Answer is A. **Explanation for Option A (Correct):** Option A, "The bilges, cabins, etc. are thoroughly ventilated," is one of the most critical safety procedures before starting a gasoline engine. Gasoline vapors are heavier than air and tend to accumulate in the lowest parts of the boat, such as the bilge. These vapors are highly explosive. Before starting the engine, running the bilge blower for at least four minutes (or as recommended by regulation) is mandatory to expel any potentially explosive fumes, preventing a catastrophic fire or explosion when the engine ignition system or starter motor sparks. **Explanation for Other Options (Incorrect):** * **B) The gasoline tank is full:** While it's wise to have sufficient fuel, the level of gasoline in the tank (full or otherwise) has no direct bearing on the immediate safety procedure required *prior* to starting the engine. Starting with a full tank does not prevent an explosion caused by accumulated vapors. * **C) You have fresh water on board:** Having fresh drinking water is important for comfort and preparedness on any extended trip, but it is a matter of provisioning, not an immediate, life-saving safety procedure required before engine startup. It is completely unrelated to the risk of explosion or fire. * **D) Each of the above is followed:** Since options B and C are not critical, mandatory safety procedures prior to engine start-up, this encompassing option is incorrect. Only ventilation (A) addresses the primary and most immediate danger (explosion) associated with starting a gasoline engine.