Thanks for the input!
And yeah, Albertese's explanation is sort of what I was imagining when I added the cables. Even in space, such massive engines would put a lot of stress on a their relatively small contact point during acceleration in any direction - forwards, backwards, spinning, etc. So it just felt right to imagine that more primitive ships might need to lash down the protrusions to spread the load.
Got some more progress!
Here's a rear view, showing some of the new details on the superstructure
And here's a shot showing off the previously undepicted undercarriage, which will hold the navigational deflector and other goodies.