|>>|| No. 13211
To be honest mate if you've come straight from a 9-5 without an engineering qualification you'd really struggle to find a place. Most of the work for british people is generally on cruise ships, and the roles you are referring to are usually filled by Filipinos or Indonesians.
Your best bet otherwise is literally to go down a marina with copies of your CV and a sincere work ethic, where you might get work as a deck rating, the pay for which will be very good but the work rotations are gruelling (9+ months on).
For me, my day-to-day (as a cadet, mind) is to shadow the people in the position I'll eventually be filling.
That position, though, is one which is in charge of looking after the ship's power generation systems, navigation equipment and other electrical systems on board. Usually it's day-to-day maintenance, IR testing of aspects of the generator, servicing and overhauling of equipment. There's lots of little faffy jobs on cruise as well, for instance I spent a lot of time looking after the on-board telecoms, installing and servicing emergency buttons, things like that.
Hope that helps.
Shifts are 12 hours, 7 days a week, plus 2 nights a week of being on-call if there's an emergency.