Of all the ships I have been on the bridge systems such as radars, gps, radios etc have been maintained by elctricians, who are engine officers, or service people from shoreside representing that certain brand of equipment if the problems are more serious.
When it comes to the definition of officers in the military I have no knowledge about that, only who is officers and not onboard a ship.
To giratsea's disappointment this is not a big deal to me, I just think it's interesting to see the reactions of my point of view. I'm repeating what I've said earlier, but not seem to go through: Even If the mentioned crew is not "real officers in the right term, they are certainly having enough responsibility to deserve officer status and privileges. But being an officer at sea is something you become after a specific education and a specific set of safety and medical courses and most of all after years at sea.