Long story short, the Navy declassified the blueprints for the aircraft carrier I used to work on. The scans come from the original 1953 drafts that were hand drawn on 73x12 inch sheets at 1:192 scale (1/16th in = 1 foot)

The scans are in a bad way though. The original jpegs are suffering from a semi-low DPI, compression artifacting, and are a bit skewed in places possibly to do the size of the original prints. (There are also redacted bits that I can fill in from Damage Control maps, also released) I cleaned it the plans as best I could in Gimp, but are still not great so I decided to redraft them in Inkscape.

It's going swimmingly, but now running into issues about 240 feet back on a 1000 foot boat. I'm first working on the double bottom, where the Keel is located to work as a frame for the rest of the ship. Inkscape is just having a bad time with the svg. It's only 8MB but I having massive lag when doing cut/paste and grid snapping. I'm not doing anything fancy, It's just a simple B&W trace of the original plans. Three layers. The bottom layer is the white background. The mid is the original scan, and the top is the work layer that I have been tracing in using modular 4ftx4ft objects for manholes, lighting holes and bulkheads.

Here is a link to an Inskape screenshot. It's better that the original that can be found here.

Any ideas? I would think with only 8MB, (and my system have 4GB) I should be able to handle the whole ship and not have it choke on the first 3rd of the keel.

I have found that the size of the file is not really the issue because vector and svg is efficiently stored but very quickly bogs down when rendering to the screen. In this case your trace operation has resulted in a lot of nodes, probably in the thousands, which IS has to calculate each time you move or zoom.
No one (except me, perhaps) wants to draw by hand when one can generate a drawing automatically but there is much more beauty in tracing by hand in inkscape than in any autotraced drawing. You'll also get a file size a tiny fraction of what you're trying to use now!

Snapping contributes big time to lagging. I`ll recommend using the shortcut (Shift+5) for enabling/disabling the snapping. While enabled, and while you drag around the cut out pieces, snapping reaches for any and every node you approach. Hence, the lagging.

Also, if you change the view to Outline (Ctrl+Num5 / Normal-No filters-Outline), you`ll see all lines in the same width but it also might improve the handling. I`ll suggest grouping of the elements with specific widths or even placing them on different layers.

You don`t need a layer for the background. Inkscape has the Doc. Properties (Ctrl+Shift+D) where you may chose the color and even transparency of the background.