yes, rendering can use a lot of memory.
However, I would suggest sticking with quality rendering.
Render fully only those objects which the camera can see, as it were.
Switch on/off layers/xrefs as required.
Items/objects/models in the background/further away can be replaced with images.
Kai uses this trick to create a forest of trees.
You can cut your ship into sections either way.
Have a think about it.