Or we would see a Minke whale... the smaller cousin of the Finback. Minkes are 30-35 feet while Finbacks are 70-80 feet. One way to tell a minke from a finback: when a Minke comes to the surface, you can see the blowhole and dorsal fin at the same time. When a finback blows a lot of sleek muscular back slides by before the dorsal shows itself.
We ended up calling them "stinky Minkes" because the were so frustrating to watch. Someone might spot one but by the time we got the boat turned around and everybodies attention... the were gone! That was our problem, they were going about their lives just as they were supposed to.