Wrong. I hired one of the marina owners to teach my wife to dock and
maneuver our 32 footer....I did not have the patience.

***************

Simply because you did something, that doesn't make the practice
correct.
Unless the marina owner was a licensed master (coulda been, but the
qualification you suggested was merely "a marina employee" and the
majority of marinas probably don't have even a single licensed master
on staff) hiring that person to do training was a violation of the law
and almost certainly of your insurance coverage. You got away with it,
(assuming the marina owner wasn't a licensed master), because nothing
happened. Suggesting others do the same is like recommending Russian
Roulette, "I did it, once, and nothing happened so everybody else
should follow my example."

Who would hire the dock boy? Somebody hoping to get the job done by the
lowest bidder.
However, if you want to refute my statement, you might experiment with
including the entire phrase........."You can't simply hire the dock boy
or some other marina worker to show you the ropes...."

As you will now reply with "where did I say the marina owner wasn't a
licensed master?", I'll save you the keystrokes and admit that you did
not. However, if you knew enough to be sure the person you hired had
the appropriate license, you should have included that specification in
your advice, not merely suggested a "marina employee" to teach docking
and seamanship aboard a boat.