We went out to watch the inshore
racing in
Singapore in 2009. Wickedly fast boats. We had to go to a skipper's briefing because we would be in close proximity.
Basically we were told do not try any evasive maneuvers if they appear to be headed at you. They know what they are doing. You can see from the photos how close we were and yes they were headed right at us...
What was amazing was how fast they accelerated after a gybe.