Agreed on all points.
Since my docks are located on the Oakland Estuary, we have to pass through the main port of Oakland every time we head to the bay. The estuary isn't very wide, only a few hundred yards, so when the tugs are laying up against a ship pushing it into it's berth any slow moving boat that passes through their prop wash will suddenly go for a pretty exciting sideways ride.
And out in the bay where the ships are up to speed you never really worry about their wakes. Waterline makes all the differnece.
On the other hand, a large powerboat in the 40'-70' range, a ferry, or other something else along those lines can make one heck of a wake! As an example, here are some shots I took while testing a 65 footer, accelerating from about 10 to 30 knots. To give some frame of refernce, the camera is maybe 8-10 feet above the waterline and the dinghy is a 14' RIB riding on the swim platform. That kind of wake will trip up anybody!
Don
'01 22 Classic, 502/B1
And a bunch of other stuff
"If everything seems under control, you're just not going fast enough" - Mario Andretti