Maxwell rendering from Rhino construction, of the turret I designed for the Wasp fantasy ship from the Spelljammer setting :) In this image I'm showing the design work for the turret as I was puzzling out how, practically, it could be built and operated using low levels of tech (though the setting also allows for very high powered magic and down right weird stuff, especially when gnomes are around...) I rendered the turret walls in glass, so you can see the rollers that support the floor and walls. There are two banks of rollers, one inside the walls (pinned through by the bars used by people to push and rotate the turret), and another under the floor. The turret itself would hold a ballista or catapult. The capstans behind it are used to align the ship's wings as that's another refinement I added as original description of spelljammer ships notes they used crew to aid with manouverability and sails/rigging are important (Spelljammer is very weird and would take a long time to explain WHY you'd want wings on a spaceship, lol, Wikipedia has info on Spelljammer if you wish to read up) Spelljammer is a fantasy space setting for Dungeons and Dragons that was out in the early in 90s, and I'm rebuilding the gloriously weird ships in 3d, while trying to make some of the designs more practical and fix differences between descriptions, deckplans and sizes. This ship type, the Wasp, was one used by humans and lizardmen as a light merchantman and raider, and is a common ship in fantasy-space.