[inimino]

You can define engineering in many ways, and none of them is equally right in every possible context in which the term is used (so it has this in common with every other word).

However, there are some ideas clustered around that seem to have something to do with it. Engineering on a ship has to do with electrical and mechanical systems, and in a highly constrained set of outcomes, essentially reducible to a single bit at any point in time. (Either the systems are up and running right now, or they aren't.) Within this system of evaluation of outcomes, it's not surprising if the engineers in this context aren't using maths every day but are engaged mainly in more practical actions. However, you can be sure that they know a lot of safety tolerances and operational characteristics of various ship systems that would be characterized as mathematical, even if they are mostly operating well within tolerances that make these operations routine.

One reason why people argue about "software engineering" is that there are authors who define it specifically to include scientistic or bureaucratic rituals that have no mathematical underpinning, while excluding the difficult mathy bits of engineering. The further you get from actual engineering, the more common this definition gets.

EWD1165 "There is still a war going on.":

https://www.cs.utexas.edu/users/EWD/ewd11xx/EWD1165.PDF