VHF communication for overtaking on the ICW is a written rule but often ignored, however the call is quick and appreciated. We called a tug with a floating crane and were told which side he preferred us to pass on, which as it was a narrow and shallow channel (yet in a wide open expanse of water) was helpful.
As we always did, we wave to all (except PWCs there are exceptions!) regardless of power or sail and do the same here. Roughly 90% waved back here so far, the other 10% mostly raggies did not but employed the straight ahead stare tactic, their loss.