I visited a maritime museum which showed a film clip from WW2 about a radio broadcast set up so that merchant sailors could get messages from their family.

I am unable to find an online resource with more info, though I know from general reading and from visiting WW2-era museum ships that sailors were listening to radio shows while at sea. I assume it was all shortwave, back in the time when radio dials included city names.

I was reading Moby Dick earlier this year and was surprised that the mail service seemed to be "I am a ship returning to port, I have a bag of letters meant for sailors SOMEWHERE in the ocean, I will give it to this ONE ship and maybe they will cross paths with these sailors". Curious how often the messages ended up getting to where they needed to go.