For example, I’m paddling, get rolled in surf, and dislocate my shoulder coming up. I’m out of my kayak on the beach of a deserted barrier island and it’s getting dark.
I’m paddling in an area I haven’t been before, I thought I could navigate back to the landing through the salt marshes using my chart but now I’m confused as to where I even am, and it’s getting dark.
I’m paddling at the mouth of a narrow bay, working harder than I thought to get back to the ramp. The wind is blowing against me and the tidal currents, which have at least an hour to go to max ebb, aren’t helping. My arms are staring to cramp. I’m being flushed out to sea, and it’s getting dark.
Not sure that any of these scenarios qualify as grave and imminent danger but I need assistance in each. Maybe I should go to channel 16 and say something like “Boater in distress” rather than mayday???
If the circumstances do not change for the better and the outcome will be death or grave bodily injury then, yes that likely sounds like a mayday. Less than that the accepted protocol is to call a “Pan-Pan.” That’s considered urgent but not yet life threatening. Stranded on the beach but no imminent threat of death, for example. You can always change it to mayday if things go downhill.
A Mayday is an all stations call (as are Pan-Pan and Securite.) and anyone in earshot and able to is expected to render assistance. If you’re standing on the beach eating a sandwich, some might not view it quite so dire a situation.
If you are in Rescue 21 coverage even with a handheld, the CG should be able to receive you and you can call them on 16.
Most any basic boat guide like Chapman’s has radio usage explained.
I would call all of the above a possible candidate for Mayday, because you are alone and lack the resources to correct the situation. The danger will be grave and imminent danger fairly quickly, and you don’t want to risk making the call when you really are incapacitated and may have trouble communicating your location. Or are swimming because you pushed it too far fighting the tidal currents and got unstable due to exhaustion.
Maybe call a PanPan for being lost in the marsh, in case it gets a response from someone who could give you verbal info to get out of the fix? Because in that case you are not at risk of near term physical incapacitation. Unless it is winter.
There are three phrases that you might hear on a VHF radio, and they all relate to safety. MAYDAY - distress signal, requires the most urgent response. This signal is only to be used when a person, or boat is threatened by grave or imminent danger , and requires assistance.
I don’t think anyone would fault you for calling a mayday for any of those. Or for using Pan Pan for any of them instead.
That said, I’d probably not use a mayday in the lost in the marsh one (but instead stick to pan pan). I am thinking the likely outcome of not finding your way out is an uncomfortable night in your kayak or on a beach.