This design was originally inspired by a quick drawing of a P.F. Sloan-Class escort from Traveller. I picked up a set of GURPS Traveller books over the years, mostly as reference texts (and in general GURPS books are very good reference books), and I saw one of these ships as an unnamed escort in one of the images. At the time I was needing to have a design for an Ibizan heavy cruiser that mounted six railguns forward, and it seemed to actually be a good fit: central core surrounded by six cylinders in a hexagonal pattern.
Of course, once that was done it was only a short step towards extrapolating what larger and smaller ships would look like on the same broad pattern. One of the more interesting/annoying parts of it was how the various cylinders attached to the main hull. I eventually settled on having an interstitial filling that filled in the various empty gaps between the perimeter cylinders and the main core. The empty spaces otherwise would have seemed to be VERY odd looking for the design. I figure if/whenever I do the deck plans for this one, each cylinder will be its own self contained setup, and the various interconnecting spaces will be used for water/air/fuel/waste tankage to support the ship’s operation.