Have older AM radio with ferrite antenna? A few parts can add the 1600 to 3600 kc range. I am not sure if Marine Band is in that range now.
Coil on left is regular AM ferrite antenna. Switching DPDT switch to right connects two adjustable 30 - 69 microhenry coils. The 10 foot antenna with 250 mfd ceramic disk is not shown in simulator which connects to center terminals of DPDT switch.
The bottom wires go to AM Radio Tuning Capacitor Antenna Section of radio and the other wire to AM Radio Tuning Capacitor Oscillator Section.
The article caught my interest. You might enjoy looking at page 172 and 173 of:
https://books.google.com/books/about/Popular_Mechanics.html?id=RuMDAAAAMBAJ
