Question 18General Subjects - 1st Asst/Chief

The correct answer is B) Two. To take suction on the lube oil drain tank cofferdam, two suction side valves must be open. This is because the bilge pump requires two open valves to draw liquid from the cofferdam - one valve to allow the liquid to enter the suction side of the pump, and another valve to allow the liquid to be discharged from the pump. The other answer choices are incorrect because one valve is not enough to allow the liquid to flow into and out of the pump (A), three valves would be unnecessarily complex (C), and four valves would be an excessive number for this simple suction operation (D).