ET(MESM) is a new branch introduced to sort out some of the manpower issues within other departments (namely Weapons Engineering). You will train up to degree level in mechanical/electrical engineering so a working knowledge of mathematics and mechanics would be useful. Be ready for general engineering questions such as where electricity comes from, how a diesel engine works etc but dont worry too much if your a complete novice. The interview will be aimed at discovering if you have the potential for the RN to train you as one of its skilled technicians. Good Luck!