These designs and models were all intended as part of a space animation set on the asteroid Vesta which I was planning, but which ended up generating more work than I likely will be able to do in a reasonable amount of time. I probably won't complete most of these models, but I may still finish the tug spaceship as I'm quite happy with the designs and concept model.
The basic idea of these designs was to translate the concepts of container ships and tugboats into a space environment, staying true to physics and engineering while also calling on familiar marine design elements, making it instantly obvious what these ships are for.
The space tug design, like its real-life counterpart, is intended to push and pull the much larger freighters to help maneuver them in and out of berths in a space port. To facilitate this, these tugs are equipped with many oversized maneuvering thrusters, a very large engine, and various attachment mechanisms. As a reference to real life tugs, I chose a rounded hull design with a raised control room surrounded by windows. In space, the concepts of up and down don't really exist, but I decided that design-wise, the "top" of this ship would be the part facing away from freighters that it's pushing. This allowed me to further the "boat" look, by creating an obvious up and down.
The design process for the freighter was simpler. With the large scale of it, it was difficult to find many ways to relate it to real-life container ships realistically. Luckily I think that the shipping containers are enough of a clue, and they make up the majority of the design. Other than containers, the design consists of an engine, large radiator find, exposed fuel tanks, and scaffold-like trusses holding everything together.