The discussion has covered the topic well. In point of practice, pleasure boats routinely idle down to 2-3 mph in 5mph zones for minimum wake. Even so, they upset docked boaters on the BBQ. A 16' speedboat at 'idle' will leave enough wake to swamp a sculling boat, so there will always be yelling involved. A small speedboat actually makes bigger waves on any throttle whatsoever vs. up on plane because the hull
is pushed 'through' the water
not riding over it (a tunnel boat has virtually no wake at 90mph, since it rides on a cushion of air.
boats observe 'minimum steerage way' greater than 5mph or operate via tug/tow. A 360' submarine will lose steerage and 'drift' at <5 mph (hence the tug).
No wake zones are enforced by law enforcement via the rules of common sense. If your wake is upsetting docked boats enough to cause potential damage, expect flashing lights and a ticket. If you are at 5 mph in a no wake zone and you pass a sculling boat and don't 'slow down' and shift/drift by resulting in swamping the scull, expect yelling, gestures, and potentially flashing lights and a ticket EVEN IF WITHIN POSTED SPEED LIMITS.
Sailboats hurtling through mooring
areas at 6 knots+ on a windy day are 'operating recklessly' and expected to douse sail to carefully negotiate though an obstacle field.
Protocol is, in fact, loose sail/shift neutral upon approach and/or at closest point if in doubt or it helps the affected boater(s). The smaller the boat, the more the expected courtesy. Commercial
ships are basically exempt due to confined maneuvering. A USN Aircraft carrier has sunk boats with waves while stopped at the pier simply by dropping anchor
. If it was you, you were clearly too close (which is also illegal).
In the end, if what you are doing looks stupid to a 3rd party observer, chances are it will to the USCG/State Police, Harbor Patrol, or USCG Auxiliary. Being surprised by the results is always the operator's fault.
USN/USCG Ship Inspector