Thanks everyone for the reply. I was hoping to avoid purchasing an airbrush, and thought a brown spraycan primer would be the most economical and fastest way to get a basecoat onto the pirate ship. It has such huge surface area that it's really not a miniature; it's a model. The Army Painter rattlecans are spendy, and I might as well invest the cost into an airbrush.
It's not only the pirate ships (I bought 2). Also coming are a few expansions and the core set, as well as 6 dragons, so I need some way to prime that is both cost and time effective. It sounds like airbrush priming might be the way to go.