Bob is CORRECT!

I hate that I know this. I am in fact studying for the PE exam later this month at this very momment (at least I'm supposed to be).

The concept Bob describes is called the Mass Moment of Inertia, defined as follows: I=mL^2/12, where L is the length of the slender rod (or oar) and m is the mass of the oar. Increase the mass by counter balancing, the numerator increases as does the Momment of Inertia.

Do you want to talk Work & Energy, next? Someone shoot me please.