Obligatory Far Side cartoon: http://4.bp.blogspot.com/_qMABJs3fRaQ/R0BNQnDXuVI/AAAAAAAAAeI/h9GXPMQJuZk/s320/Rowing+in+Circle001.jpg
And, of course, Mythbusters proved it was possible for him to have done so, by having Jamie Hyneman do it!
Another comic strip (on my office bull board) shows the interior of a galley with only 3 rowers and the drum beater says to the captain, “You said you wanted this place to be run like a business”.