I've seen any number of model ship building jigs that hold the hull while you work or paint. Many are made of laser cut wood, some are 3d printed. Most are, with shipping, somewhat expensive. Working with an avid ship builder, I worked on a version that could be printed easily at home. Except for a number of standard ¼ inch hex head screws, all of this is 3d printed. Imperial measurements were chosen for the fasteners due to commonality in the US (nearly any hardware store or ‘big box’ store sells them). I have a version built around M5 bolts, but it is unfinished.
Printing Notes:
All of my test prints were a .4mm nozzle, printed with 4 walls at .2mm layer height. Infill was set to 20% adaptive cubic. Adjust as desired for speed/strength.
The STL's are in the proper print orientation to eliminate support usage. The actual parts that hold the model could potentially be printed in a different orientation to improve strength, but supports would be needed.
Hardware:
The only non-printed parts needed are 8 or more ¾ inch long ¼ inch hex head screws/bolts, https://www.mcmaster.com/92865A540
and 8 or more nuts. https://www.mcmaster.com/95462A029
Assembly:
The “long” base in two parts should friction fit together via the dovetails. I used a flat table and a nylon mallet to tap them together.
The “short” base requires no assembly.
Both bases need uprights (two or more), cross bars (one each), model holders (two per cross bar), 4 bolts/cross bar and uprights unit.
TPU (print a small square to fit the arms) or foam additions to holders will help hold the model in place and avoid scratches. Rubber washers might be added to create more friction on adjustable parts to make it more stable.
-edit, added some narrower upright holders.
The author marked this model as their own original creation.