Question 147Steam Plants - Assistant Engineer

The correct answer is A) proportional action. A single element boiler feed water regulating system used aboard ship utilizes proportional action. This means the control system adjusts the feed water flow to the boiler in direct proportion to the deviation between the actual water level and the desired water level in the boiler. This simple proportional control is sufficient to maintain a relatively stable water level in the boiler without the need for more complex control actions like reset or rate. The other options are incorrect because they describe more advanced control actions that are not necessary for a basic single element boiler feed water regulating system. Options B, C, and D would involve additional control features beyond just proportional action.