Firstly, good luck with your application. As mentioned previously, the choice of specialisation is no longer yours, so you may end up firmly rooted in the North of Scotland spewing about the world's oceans or feeling very important in the back of a Waddo mushroom. You need to think carefully whether or not you are prepared to accept the alternatives to "crewman". There will be a lot of hard work and effort required between applying and being selected for a particular role, some 24 weeks into profesional training (?), so you need to be sure that if you are offered something other than crewman you would be happy, otherwise a lot of your time, sweat and effort will have been in vain...Enjoy!