Size based modifiers to space detection/combat

[Condottiere]

Now it's inertia; based on legacy designs, which were driven by historical expectations.

 

[AnotherDilbert]

... I've always wondered why gravitic drives are at the rear of the ship and have exhausts,

I have had it explained to me recently: The first edition of CT (1977) had reaction drives expelling reaction mass to the rear to accelerate (yet without using any actual reaction mass). Hence early illustrations had glowing nozzles.

In the second edition of CT (1981) the reaction drives were replaced with gravitic reactionless drives , but the imagery of the early illustrations have remained.

why jump drives are not in the center of the ship if generating a bubble...

A jump bubble expanding from the centre of the ship would tear it apart? If memory serves, the jump bubble is created in the hull. So a large part of the jump drive is built into the hull.

There is also a central energy capacitor node that very temporarily stores the energy needed to form the jump bubble.