Here's a recording that W1YT mailed to me shortly after that visit of me on my Vibroplex Original using the SS KING/WAKL high frequency transmitter on 7020 kHz.  Ship radio equipment was nearly always separate transmitters and received as we operated duplex which is one frequency for transmit, one for receive.  Like transmitting with SLIDELL LOUISIANA RADIO WNU he used 478 kHz and ships used 468 kHz or 480 kHz. 

Here's the recording, you can share this. 

Here's a version popular in Japan with a Gulf of Mexico thunderstorm mixed in. 

73

David N1EA