When you are the Engineering Officer of the Watch (EOW) you are in charge of the engine room and responsible for the proper operation of all machinery and the safety of all personnel in the engine room. These are your primary duties, as STCW clearly states:
Officers in charge of an engineering watch shall not be assigned or undertake any duties which would interfere with their supervisory duties in respect of the main propulsion system and ancillary equipment. They shall keep the main propulsion plant and auxiliary systems under constant supervision until properly relieved, and shall periodically inspect the machinery in their charge. They shall also ensure that adequate rounds of the machinery and steering-gear spacers are made for the purpose of observing and reporting equipment malfunctions or breakdowns, performing or direction routine adjustments, required upkeep and any other necessary tasks.
―STCW Code Section A-VIII/2 part 3-2 ¶ 69
As long as you are on watch, you are in charge and responsible. Your responsibility only ends when you are properly relieved. Even if the chief engineer is in the engineroom, you remain responsible for the watch unless he specifically informs you that he has taken charge.
The authority of the Cadet Engineer of the watch aboard the Patriot State is more limited than that of the watch engineer, so as a cadet you should get permission of the watch officer before carrying out any operations described below.
