The Coast Guard often issues pan-pans when they receive maydays from boaters in trouble.
Here's an example:http://www.associatedcontent.com/audio/16776/sea_kayak_rescues_vhf_...
In the case above, along the coastal mid-Atlantic US, the captain of a sinking fishing boat broadcasts a harried mayday. Hampton Roads, Virginia Coast Guard picks up the call. The captain can't give his gps coordinates, but can describe his position off local landmarks. He then activates his EPRIB and hops into his
The CG watchstander immediately issues a pan-pan asking all local boaters be on the lookout for the boater in trouble.
The call illustrates one of the beauties of marine vhf radio. Any boater whose radio is on and tuned to channel 16 can hear these requests for help. And if you're a kayaker, you can pitch in to help if you are willing and able.