Question 125Steam Plants - Assistant Engineer

The correct answer is A) superheater outlet. The main steam stop valve on a "D" type marine boiler is located at the superheater outlet. This is because the main steam stop valve controls the flow of steam from the boiler to the rest of the engine/propulsion system. The superheater outlet is the point where the steam exits the superheater and enters the steam piping, so this is the logical location for the main steam stop valve. The other options are incorrect because the desuperheater is not part of the "D" type boiler configuration, and the superheater inlet is not the appropriate location for the main steam stop valve.