Hmm, I'm going to assume a bit, since I don't fully know what you meant with expanding. a) you've tried to scale your model, to make it larger. Did you perhaps use the scale option (can be selected by clicking too long on that button), that only works for one direction (x/y/z) ? b) if you haven't built the model's main body yet or are having trouble with that, I suggest the following. For the Mc40a I used a 12-sided, segmented sphere, that I converted to an editable mesh, later. This requires some foresight, though. So, give it as many segments, as you think it needs and try a rough sculpting, then. This stage often shows, whether you need to start again with more segments or not. Small addons, like bridge towers don't need to come off the segments, btw. They can be modelled separately and welded on the ship later with the "attach" modifier.