Hm... one possible way to do it: Take a Clockwork Leviathan, remove its ability to "eat" things, and replace it with the ability to safely transport its carrying capacity in materials/crew around, with volume assumed to not be a problem.
Ultimate Combat chapter 4 is all about vehicles, have you had a peek there? No clockwork ship's specifically, though there is an airship with an alchemical engine.
I had read it before, and I have now reread it. Thanks for the suggestion, but it didn't provide any information that was particularly useful. Still, it was a decent refresher in how vehicles work.