Dave: No comments from the peanut gallery.

I'm using the term "speedboats" to describe boats which sound like they have
(and probably do have) a pair of 400+ cubic inch motors in the back? In
order to achieve their purpose (speed), is it absolutely necessary for them
to be as noisy as they are, or are they just designed that way, in the same
way some morons alter their motorcycles because "loud pipes save lives"?
And, when they're idling, why do they sound (and smell) as if the engines
are only firing on half their cylinders?