I would say two - it is a relatively small ship, although I would like to slightly...exaggerate it's size
I would say two men per oar though.
Also, please bear with me for the occasional spelling mistake - a few of the keys on my keyboard are refusing to work unless stamped upon very heavily, so I apologise if there are sporadically missing 'w's, 'a's or 'o's. Or 'q's, actually, but then, I don't use that many of them anyhoo...