- I respond to a CG call that someone fell off a bridge (in the water).
I get there, nobody else is there. Flare to attract others?


No. Report to the CG that you have arrived on the scene and wait for
additional instructions or permission to leave.

- I see a powerboat drifting under wind and waves into a cliff. I know
it WILL be nasty but isnt yet. My ETA would be 10 minutes. Wait, til
they crash, then mayday? Wait til they crash, go there, then mayday?


You have observed a situation that appears to place the vessel and or
the crew in imminent peril. A Mayday is appropriate for a boat drifting
toward rocks. If the vessel were merely drifting around in an open
area, far from any danger, it may be more of a hazard to navigation
than in immediate peril, and one of the less urgent radio calls might
then be appropriate.


- From the distance I see that 2 boats collided, but dont kow if
anybody got hurt. Mayday or go there first?


That might be a judgment call. Was the "collision" just a glancing
broadside bump, or is there
evidence that one of the vessels is disabled and/or structurally
compromised? Myself, I'd wait a10-15 seconds to see if either vessel
reported the collision on the radio. (The last thing the CG needs is a
distant observer clogging up 16 when they could be getting first hand
information from somebody involved in the incident). Then I would make
probably one attempt to raise the vessels involved on the VHF to
inquire about the situation. Meanwhile, I'd change course to stand by
near enough to be useful- depending on the situation. Ultimately, if
one of the vessels appeared to be sinking, somebody was in the water,
or there was evidence of fire I would radio a Mayday to report a
serious collision. The key factor is whether a life or a vessel is in
immediate danger.